Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
439 AM AST Wed Sep 24 2025

.KEY MESSAGES...

* A robust tropical wave (AL94) will cross the region today into
Thursday, bringing periods of squally weather with bands of
heavy showers, thunderstorms, and gusty winds.

* Elevated to significant flooding risks are anticipated from the
heavy rainfall, with potential for urban and small stream
flooding, flash flooding, rapid river rises, and landslides in
steep terrain.

* Hazardous marine conditions are expected as AL94 moves across
the region, with Small Craft Advisories in effect. Increasing
winds and seas will create dangerous conditions for mariners.

* An extended wet period will continue into the weekend, as deep
tropical moisture from AL94 and AL93, moving north of the area,
sustains rounds of showers and thunderstorms.

* For the U.S. Virgin Islands: Squally weather will persist
through Thursday with heavy showers, thunderstorms, gusty winds,
and hazardous marine conditions. Additional rounds of showers
are expected into the weekend, maintaining a risk of flooding in
vulnerable areas before gradual improvement by midweek of next
week.

&&

.SHORT TERM...Today through Friday...

Tranquil conditions prevailed overnight across the region, with only
brief passing showers affecting eastern Puerto Rico and the US
Virgin Islands under light northeasterly winds that gradually
transitioned to more east to southeasterly. A few stronger showers
with isolated thunderstorms developed over the surrounding
waters, occasionally producing lightning south of Saint Croix and
northwest of Aguadilla, though no products were required.
Overnight lows ranged from the upper 70s to the low 80s in coastal
and urban areas, while interior valleys and higher terrain cooled
to the upper 60s to mids, slightly warmer than the previous
nights.

Unlike the last several days, heat will not be the main hazard
today. Instead, attention shifts to a flooding threat as a tropical
wave currently monitored by the National Hurricane Center steadily
approaches our region. Winds will gradually veer to the south,
favoring enhanced moisture transport and heavier rainfall along the
eastern and northern portions of Puerto Rico and the US Virgin
Islands. Model guidance shows above-normal precipitable water values
for this time of year, with mid-level temperatures near -7 degrees
C, both of which support deep convective development.

By late today into Thursday, interaction between the tropical wave
and an upper-level low will maximize instability and rainfall
potential. The most widespread and intense activity is expected
during this window, initially impacting the Virgin Islands before
spreading across Puerto Rico. Therefore, periods of squally weather,
heavy rainfall, and thunderstorms will bring the potential for
significant impacts, including rainfall totals of 2 to 6 inches,
along the northern and eastern half of PR and the US Virgin Islands.
The unsettled and unstable weather pattern will likely persist
through the end of the workweek. However, showers and thunderstorms
are expected to be less widespread after Thursday.

Given already saturated soils across the northern and western half
of Puerto Rico, as well as St. Thomas and western St. Croix, risks
include urban and small stream flooding, flash flooding, rapid river
rises, coastal water surges, and landslides in steep terrain.

Residents and visitors should remain alert for any changes in the
forecast, in order to make informed decisions. For further details,
refer to the hydrology section.

.LONG TERM...Saturday through Wednesday...

For this weekend, soils across the region will likely remain
saturated and streamflows elevated after several days of heavy
rainfall. These antecedent conditions increase the area’s
sensitivity to additional rainfall, meaning even moderate showers
could quickly trigger urban and small stream flooding, as well as
isolated landslides in steep terrain.

This weekend, little change is expected in the overall pattern
suggested by previous model cycles. A deep-layer southerly flow,
reinforced by the northward movement of Invest AL94 and AL93, will
continue transporting abundant tropical moisture into the region.
Precipitable water values will remain above normal, generally at
or above 2 inches, maintaining a moist and unstable environment.
In combination with daytime heating and sea breeze convergence,
this will favor frequent rounds of showers and thunderstorms,
particularly during the afternoon. Activity will tend to focus on
southern and eastern Puerto Rico and the smaller islands overnight
and during the morning, then shift toward the interior and
northwestern municipalities in the afternoon. The prevailing
southerly flow will also enhance rainfall potential along the
northern slopes of Puerto Rico.

The ECMWF Extreme Forecast Index now signals the potential for
extreme precipitation, especially across the southern and eastern
portions of the forecast area, although ensemble spread maintains
some uncertainty regarding the exact magnitude and focus.
Regardless, given antecedent soil conditions, the potential for
flooding impacts will remain elevated through the weekend and into
early next week.

Conditions are expected to gradually improve beginning Tuesday as
the moisture plumes shift north and precipitable water values drop
to near or slightly below seasonal levels, around 1.5 to 1.6 inches.
With this drying trend, shower and thunderstorm activity will become
more isolated, and the flood threat should begin to diminish
compared to the weekend. Still, isolated afternoon convection will
remain possible, especially across the western and interior portions
of Puerto Rico.

In addition to rainfall hazards, a persistent southerly flow will
maintain above-normal temperatures and oppressive heat indices
across coastal and urban areas. Extreme Heat Warnings or Advisories
are likely to be needed through much of the period, particularly
over the weekend when moisture levels and heat combine to create
dangerous conditions.


&&

.AVIATION...
(06Z TAFs)

All TAF sites should experience VFR conditions. However,
after 24/14Z, -SHRA/VCTS could affect TIST, TISX, and TJSJ. But
after 24/17Z, TSRA should prompt periods of MVFR conditions
across most TAF sites, with the heaviest TS activity as the
vigorous Tropical Wave being monitored by the National Hurricane
Center moves closer to the region. Winds will remain from the E-SE
and gradually become more S from 24/15-24/22Z at 8–15 kts and
higher gusts near the heaviest RA and TS associated to the
tropical wave.


&&

.MARINE...

Today, a vigorous tropical wave will move into the islands,
increasing the potential for thunderstorms and leading to localized
hazardous marine conditions. These storms may produce frequent
lightning over exposed waters. In addition, an increase in surface
winds is forecast through at least late tonight, particularly across
the offshore Atlantic waters, Anegada Passage and waters east of
Puerto Rico, around Vieques, Culebra, and St. Thomas, where Small
Craft Advisories are in effect. Seas up to 7 feet, particularly
across the offshore Atlantic waters and Anegada Passage.


&&

.BEACH FORECAST...

Increasing winds and choppy seas as AL94 crosses the region will
maintain hazardous conditions, particularly along the Atlantic-
facing beaches. As a result, a moderate rip current risk will
persist across the northern and eastern beaches of Puerto Rico,
Vieques, Culebra, and the U.S. Virgin Islands. Beachgoers are
urged to exercise caution and avoid swimming in high-risk areas.

In addition, thunderstorms associated with AL94 will pose
significant hazards at the coast. Frequent lightning strikes,
gusty winds, and heavy rainfall may lead to dangerous conditions,
including sudden reductions in visibility and localized flooding
near the shoreline. Remember: if thunder roars, go indoors.
Swimmers and boaters should immediately seek shelter when storms
approach.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
422 AM AST Thu Sep 25 2025

.KEY MESSAGES...

* The wet pattern will persist during the day as trailing
moisture from the tropical wave (Invest 94L) continues to
affect the local islands. The additional rainfall accumulations
will exacerbate flooding, especially across eastern sections of
Puerto Rico.

* For the U.S. Virgin Islands, additional shower activity is
expected for the rest of the morning, enhancing urban flooding
in already affected areas.

* Tropical moisture from the tropical wave (Invest 94L) is
expected to move out of the region by Saturday, resulting in a
more typical pattern with variable days: warm mornings and
showers in the afternoons.

* For the long term, a wet pattern is forecast from Monday into
Tuesday as moisture from the tail of tropical system Humberto
moves into the region.

* Seas will remain up to 6 feet today across the offshore
Atlantic waters and a moderate risk of rip current will remain
for the northern and western coastal areas.

&&

.SHORT TERM...Today through Saturday...

Overnight, the vigorous tropical wave (AL94) continued to promote
widespread heavy showers and thunderstorms across the regional
waters. By early night, a strong band of showers developed in a
southeast-to-northwest orientation over St. Thomas. By that time,
the wave was positioned just south to southwest of Puerto Rico,
inducing a southeasterly flow over the region. This advected lines
of strong showers into the southern coastal areas of Puerto Rico,
prompting the issuance of a Flood Advisory for the southern coastal
municipalities. Elevated streamflows persisted, with rivers across
the eastern third of Puerto Rico running at or near record highs. A
Flood Warning was issued for Rio Blanco due to overflowing banks,
which rendered some roads along the river impassable.

As the wave continues its west-northwestward movement, winds are
expected to gradually shift more southerly, advecting additional
deep tropical moisture over the region. Hi-Res model guidance
suggests Thursday will maintain variable weather conditions, with
morning convection mainly affecting the southern and interior
portions of Puerto Rico and the smaller islands. During the
afternoon, additional convection may develop across the northern
slopes of Puerto Rico; however, the extent of this activity will
depend heavily on cloud coverage during the day. Extensive cloud
cover, as suggested by the high-resolution guidance, could limit
instability and suppress afternoon thunderstorm development.
Nonetheless, tropical waves often behave erratically in terms of
shower and thunderstorm activity, and therefore, close monitoring is
warranted.

Looking ahead to Friday and Saturday, model guidance indicates
notable changes compared to previous cycles. Now that Tropical Storm
Humberto has developed northeast of the region, its forecasted track
has separated slightly from AL94. This shift allows drier air to
filter into the region much earlier than previously expected,
reducing the interaction between the two moisture plumes. Both the
GFS and ECMWF suggest a significant drop in mid-level relative
humidity (700-500 mb) from values above 90% to below 40%,
approaching below to near normal climatological levels. As a result,
widespread shower and thunderstorm activity will likely diminish
compared to earlier expectations. Still, localized afternoon
convection remains possible, especially where daytime heating
interacts with lingering moisture.

Despite this drier trend, uncertainty remains high regarding the
eventual evolution and interaction between AL94 and Tropical Storm
Humberto. Should the systems shift track or slow down, moisture
availability and convective potential could increase again.
Therefore, residents and local authorities should remain alert for
rapid changes in forecast conditions. With saturated soils and
elevated rivers, the threshold for flooding and landslide impacts
remains low, and even isolated strong thunderstorms could pose
significant hazards.

From Friday onward, the prevailing southerly flow combined with
ample low-level moisture will maintain above-normal temperatures and
elevated heat indices, especially across coastal and urban areas.
Periods of reduced cloud cover could further enhance daytime
heating, resulting in oppressive and potentially hazardous heat
conditions.

.LONG TERM...Sunday through Thursday....

From Sunday (September 30) through early Tuesday, the local
weather pattern across Puerto Rico and the U.S. Virgin Islands
will be influenced by two tropical systems situated over the
Atlantic. The combination of these two systems will maintain a
southeasterly wind flow across the islands. On Sunday, both global
model guidance (GFS & ECMWF) show a less wet area moving into the
region, with precipitable water values dropping to around 1.70
inches (near the 25th percentile). This brief window of reduced
moisture presence will rapidly end as Hurricane Humberto
progresses farther into the western Atlantic, leading to an
increase in tropical moisture and the tail of the tropical system
over the islands by Tuesday and into early Wednesday. During this
period, mid-level lapse rates between 700 and 500 mb will support
stable conditions aloft due to an upper-level ridge. Thus,
although moisture levels increase, instability will be limited,
and afternoon convection on Tuesday will be driven primarily by
local effects. The bulk of the showers is forecast for the
interior and northwestern sections, as well as the San Juan Metro
area.

By Wednesday, weather conditions become more typical, with PWAT
values between 1.70 and 1.9 inches and relative humidity in the
700–500 mb layer climbing above 60%, allowing for variable weather
of warm mornings with heat indices rising up to 108 degrees and
active evenings with thunderstorms and gusty winds from 12 to 5 PM.
By Thursday, conditions will evolve again as an upper- level low
moves northwestward across the Caribbean, increasing instability
over the region. Despite slightly lower moisture, with PWAT values
still around the climatological median, the presence of
instability will be sufficient to support scattered convection,
particularly during the afternoon hours across the interior and
northwestern Puerto Rico. Meanwhile, the synoptic pattern at the
surface will favor a persistent east- southeasterly wind flow,
with breezy conditions as suggest by the 925 mb wind speeds in the
model guidance, largely driven by the interaction between a
tropical system moving over the central Atlantic. This will
sustain a warm trend in the morning with an increase in heat
indices followed by afternoon thunderstorm development as the week
progresses.

&&

.AVIATION...
(06Z TAFS)

A vigorous tropical wave (AL94) will continue to bring SHRA/TSRA
across through 24/15z, with TEMPO MVFR/IFR conds possible at times
due to low CIGS/VIS, especially at TJSJ/TJPS/TIST/TISX. TSRA
activity will gradually shift to the interior and northern PR by
aftn, potentially affecting TJSJ with PROB30 for reduced VIS/CIGS.
Elsewhere, VFR conds should prevail outside of convection. Sfc winds
SE 10-15 kt, bcmg more S aft 24/15Z, with sea breeze variations at
coastal terminals. Gusts up to 25-30 kt psbl in/near SHRA/TSRA.


&&

.MARINE...

A surface high pressure over the Western Atlantic and a tropical
wave moving across the region will enhance a moderate
southeasterly wind flow across the region. The actual moisture
from the tropical wave (Invest 94L) will continue to result in
localized hazardous marine conditions near the thunderstorm
activity along the local waters. As a result, mariners are urged
to exercise caution along the exposed local waters due to seas up
to 6 feet, especially across the offshore Atlantic waters.
Improving marine conditions are forecast for the upcoming weekend
with seas up to 5 feet.

&&

.BEACH FORECAST...

There is a moderate risk of rip current along the northern and
western coastal areas of Puerto Rico, including Culebra. For the
rest of the coastal areas, the risk will remain low. Similar
coastal conditions are expected to persist from Friday into
Saturday. Thunderstorms producing frequent cloud-to-ground or
water lightning will affect the local beaches. If you hear
thunder, please seek shelter by going indoors or moving to a safe
location.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Fri Sep 26 2025

.KEY MESSAGES...

* Tropical moisture across the region from AL94, now located
north of Hispaniola, will contribute to a hot day with heat
indices reaching up to 144 degrees. As a result, a Heat
Advisory from 10 AM to 4 PM AST is in effect for the coastal
and urban areas of Puerto Rico, including Culebra & Vieques.

* For the U.S. Virgin Islands, a variable pattern will persist
through the first part of the morning, with considerable cloud
cover and limited shower activity, followed by a warm afternoon
with heat indices reaching up to 108 degrees. Therefore, there
is a heat advisory in effect from 10 AM to 4 PM AST.

* Another hot day is expected tomorrow, as surface winds from the
east- southeast promote periods of sunshine during the morning
and early afternoon.

* Tropical system Humberto moves over the Atlantic, at a safe
distance from PR and the USVI, conditions may become unstable
and moist by next Monday due to an increase in tropical
moisture across the CWA.

&&

.SHORT TERM...Today through Sunday...

A moist airmass associated with AL94 will linger over the region
today. Due to the proximity of this system, conditions will remain
somewhat unstable. With the expected break in clouds, the daytime
heating, combined with the available moisture and sea breeze
convergence, will trigger scattered afternoon convection over the
mountain ranges and west-northwest sections of PR. At the same time,
the potential remains high for observing showers and thunderstorms
over the local waters. Meanwhile, a col area is developing over the
northeastern Caribbean, and it is expected to meander close to the
USVI and offshore Atlantic waters as the slow-moving Humberto
continues to strengthen well northeast of the area. This pattern
will bring now better chances of rain across the USVI than
previously expected.

A transition to a drier, more stable, and warmer-than-average
weather pattern is expected across the islands in general through
the rest of the short-term period. Global model guidance suggests a
sharp decline in moisture content, with Precipitable Water (PWAT)
falling from wet conditions (above 75th percentile) today to near-
normal content (lower tier of the 50th percentile) through the
weekend, and a significant drop in mid-level (850-700 MB) relative
humidity, decreasing to near the 25th percentile by Sunday.
Regardless, afternoon convection is expected to develop over
portions of central and northern PR each day. This forecast is based
on the expected west/northwest movement of AL94 and TS Humberto, and
that weak ridging between the systems will bring briefly drier air
over the region. This synoptic pattern will bring light steering
winds with a southerly component over the islands, promoting 925 mb
temperatures near 24C (which is above two standard deviations).
Therefore, hot temperatures and heat indices reaching extreme
warning or heat advisory criteria can be expected each day across
the lower elevations of the islands.

.LONG TERM...Monday through Friday....

The long-term forecast remains on track for the first part of the
upcoming workweek. On Monday, the surface weather pattern across
Puerto Rico and the U.S. Virgin Islands will be influenced by
Hurricane Humberto, a tropical system located over the western
Atlantic. At the upper levels, a mid- to upper-level ridge will
dominate, providing stability over the islands. Under this
pattern, southeasterly winds will transport patches of fragmented
moisture. According to global model guidance (GFS), precipitable
water values for Monday are expected to range between 1.9 and 2
inches, supporting a variable pattern with warm conditions during
the morning, followed by convection and thunderstorms across
northwestern Puerto Rico. By Tuesday, surface moisture is expected
to decrease to near the 25th percentile as the moisture plume
shifts into the western Atlantic, leaving the islands under a much
drier pattern. This reduction will favor a more stable day with
extended periods of morning sunshine, contributing to warmer
conditions as also suggested by the 925 mb temperatures. Weaker
winds will further support a dry pattern due to the lack of a
significant sea breeze effect, particularly across western Puerto
Rico. Although surface conditions will generally be unfavorable
for widespread weather activity, isolated showers with
thunderstorms cannot be completely ruled out.

From Wednesday through Friday, 250 mb heights are forecast to
decrease, resulting in slight instability due to an upper-level
trough near the region. However, compared to yesterday’s
solutions, today’s guidance suggests less instability for
Thursday. At the surface, fragmented moisture will be steered
mainly by the prevailing winds associated with a strengthening
surface high over the central Atlantic as Hurricane Humberto
continues moving into the northwestern Atlantic. As this high
pressure builds, a weak point in the pressure gradient is expected
to develop, diminishing the 0–3 km surface winds.

&&

.AVIATION...
(06Z TAFS)

SHRA/TSRA associated to a departing tropical wave (AL94) will
continue to produce areas of MVFR across the local terminals today.
However, mainly VFR conditions are expected early in the fcst
period. Weak land/sea breeze variations will dominate the local
winds, however, an ESE component up to 10 kt is expected to prevail
during the day.

&&

.MARINE...

Gentle to light will persist as the interaction of Invest 94L and
Tropical Humberto across the region. Therefore, mariners can
expect surface winds up to 10 knots with seas up to 5 feet. An
increase in seas is forecast for the upcoming weekend as a pulse
of a brief northerly swell from a tropical system moves into the
local offshore Atlantic waters, deteriorating marine conditions
across the Atlantic waters.

&&

.BEACH FORECAST...

There is a moderate risk of rip currents along the northern and
western coastal areas of Puerto Rico, including Culebra and St.
Croix. For the remaining coastal areas, the risk will stay low.
Similar conditions are expected to persist from Friday into
Saturday. By Sunday, however, the rip current risk will increase
to high as a northerly swell generated by Tropical System Humberto
moves northward.

In addition, thunderstorms producing frequent
cloud-to-ground and cloud-to-water lightning may impact local
beaches. If you hear thunder, seek shelter indoors or move to a
safe location immediately.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
426 AM AST Sat Sep 27 2025

.KEY MESSAGES...

* An Extreme Heat Warning is in effect for all coastal areas and
urban sectors of Puerto Rico, while a Heat Advisory is in
effect for Culebra, Vieques, and the U.S. Virgin Islands. Heat
indices are forecast to peak between 12 PM and 2 PM, reaching
up to 114°F.

* An increase in moisture is forecast from Monday
into Tuesday; however, Saharan dust will also move in,
resulting in hazy skies in some isolated areas.

* A long period northeasterly swell from Hurricane Humberto will
arrive across the northern local waters, increasing seas and
breaking waves, and resulting in a high risk of rip currents.
Additionally, there is a small craft advisory in effect from
this afternoon across the offshore Atlantic waters.

&&

.SHORT TERM...Today through Monday...

For today, a meandering shallow band of moisture between Major
Hurricane Humberto to our northeast and PTC 9 near Cuba will support
an unstable and moist airmass over the local area. A weak mid-level
ridge will move over and southwest of the region by Sunday. Light to
calm winds with a southerly component will continue through the rest
of the weekend as TC Humberto moves north of the area. Therefore,
diurnally induced afternoon showers and thunderstorms, triggered by
daytime heating, weak sea breezes, and orographic lift, are expected
this afternoon. Due to the light steering winds, slow-moving
afternoon thunderstorms will increase flooding concerns, mainly
across PR. At the same time, the USVI should see an increase in
showers throughout the morning hours today, with a slight chance of
thunderstorms as they drift slowly between the Atlantic waters and
the Anegada Passage. Another surge in passing showers is expected by
late Monday.

Although a dip in PWAT is expected on Sunday, the 850-700mb lapse
rates will remain elevated; therefore, strong afternoon convection
is possible once again over portions of the Cordillera and western
PR. Elsewhere, the mid-level ridge and drop in PWAT are expected to
inhibit widespread shower development over the area. Winds will pick
up between 10-15 kt on Monday with an easterly component, and a weak
Saharan Air Layer will bring minor concentrations of Saharan dust.
However, as Humberto moves into the Southwestern Atlantic, it will
pull another shallow band of moisture over the islands, which will
enhance the diurnal convection cycle over the islands.

Temperatures and overall humidity will also remain well above
average, as the 925mb temperature and 850mb Theta-e values are
expected to continue at normal to above-normal levels, particularly
today and on Sunday. Therefore, despite the active afternoon
convection, high heat stress will be a primary concern. High
temperatures are expected to remain in the low to mid-90s across
most coastal areas, with Extreme Heat Warnings/Heat Advisories
anticipated each day.

Furthermore, swells generated by Humberto will increase the risk of
life-threatening rip currents along the north and east-facing
beaches of the islands from late today through Sunday night.

.LONG TERM...Tuesday through Saturday...

The long-term forecast remains on track. On Tuesday, the surface
pattern will continue under the influence of Hurricane Humberto
well north of the region and a strengthening surface high pressure
over the central Atlantic, resulting in a weak southeasterly wind
flow. Under this setup, the islands will experience brief
intrusions of Saharan dust with precipitable water values near 1.6
inches, close to the 25th percentile for the year. This pattern
will favor a generally stable day with calm conditions in the
morning and localized afternoon activity. Similar weather will
persist on Wednesday, while on Thursday precipitable water is
forecast to decrease further, with global model guidance
suggesting values nearly two standard deviations below normal.
Relative humidity between 700–500 mb also shows a drying trend,
supporting mostly stable mornings with only localized showers
across the interior regions.

A more unsettled pattern is expected from Friday into Saturday as
global model guidance indicates an increase in instability, with
700–500 mb lapse rates steepening and 500 mb temperatures slightly
decreasing to around –6 °C due to an upper-level trough extending
from the western Caribbean into the islands. At the surface, a
weakening of the pressure gradient is anticipated as a tropical
system moves into the northwestern Atlantic, reducing the
influence of the surface high pressure. This evolving pattern will
induce surface convergence, enhance instability, and result in
very weak steering flow. Consequently, a variable pattern is
forecast, with long-lasting afternoon showers primarily affecting
the interior, but drifting into different sections of the islands
due to weak winds.

&&

.AVIATION...

(06Z TAFS)
Mainly VFR conds expected early in the period, however, SHRA/TSRA
over the local waters may cause tempo MVFR conds across the USVI
terminals through the morning hours. Thereafter, early afternoon
convection over the northern half of PR will trigger MVFR areas in
and around TJSJ/TJBQ thru 27/21z. Weak sea breezes will dominate
the local winds, however, the low-level winds will continue with a
southerly component.

&&

.MARINE...

A pulse of a long period northeasterly swell from Major Hurricane
Humberto will increase seas across the local waters from this
afternoon through the rest of the weekend. Seas are forecast to
build to around 7 feet across the offshore Atlantic waters by 2
PM, spreading into the coastal Atlantic waters and the Anegada
Passage during the weekend. As a result, a Small Craft Advisory
will be in effect starting at noon today and extend to the coastal
Atlantic water later toninght into Sunday. Seas are expected to
remain between 7 and 8 feet across the Atlantic waters and up to
5 feet across the Caribbean waters. Improving marine conditions
are forecast from Monday as the energy from the swell diminish
across the area.

&&

.BEACH FORECAST...

A long period northeasterly swell from Major Hurricane Humberto
will increase breaking waves starting at 12 PM this afternoon. As
a result, deteriorating coastal conditions are expected,
especially across the northern coastal areas of Puerto Rico,
including beaches along the northeast PR. For Culebra, Vieques,
the U.S. Virgin Islands, and northwestern Puerto Rico, the risk
will remain moderate. However, deteriorating conditions are
forecast to spread to more coastal areas, including St. Croix,
Culebra, and the northwestern coast of Puerto Rico, during the
weekend. Improving coastal conditions are expected beginning on
Monday.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
459 AM AST Sun Sep 28 2025

.KEY MESSAGES...

* Another warm day is forecast today, with heat indices reaching
111 to 114. Therefore, an Extreme Heat Warning will be in
effect from 10 AM to 5 PM for the coastal and urban areas of
Puerto Rico, and a Heat Advisory will be in effect for Culebra,
Vieques, and the U.S. Virgin Islands for the same period.

* Localized afternoon convection is expected each afternoon from
today through Monday.

* An extended period of northeasterly swell from Hurricane Humberto
will continue to result in hazardous marine and coastal
conditions from today through late tonight.

&&

.SHORT TERM...Today through Tuesday...

Scattered showers and isolated thunderstorms were noted across the
Mona Passage into the Caribbean waters and over the offshore
Atlantic waters during the early morning hours. Some of this
activity moved over the coastal areas of southwestern PR and St.
Croix. However, rainfall amounts were not significant. Minimum
temperatures ranged from the mid-60s across the higher elevations of
PR to the mid and upper 70s across the lower elevations. In the U.S.
Virgin Islands, temperatures were from the mid-70s to the low 80s.
Winds were light with a south to southwesterly component.

Another hot day is expected due to the combination of calm to light
winds with a southerly component, and as the 925mb temperature
remains well above normal, near 24C. Therefore, maximum temperatures
will again reach the low 90s across most coastal areas, and higher
dewpoints under weak sea breezes, particularly along the northern
coast of PR, will enhance the heat threat before the onset of
afternoon showers. Heat indices could increase up to 112°F in those
areas. Hi-res and global models suggest limited shower activity
today over the islands; however, satellite data indicate that the
shallow band of moisture that produced the overnight shower and
thunderstorm activity is merging with an external rainband from TC
Humberto. As this moisture is pulled over the islands during the
day, afternoon convection is expected mainly over the Cordillera.
Under a weak southwesterly steering flow, the showers are expected
to drift northeastward into nearby municipalities.

Minor concentrations of Saharan dust are expected to move over the
islands on Monday. Although the precipitable water content is
forecast to range from below normal to normal levels, the 850-700 mb
lapse rates are expected to remain in the 50th percentile throughout
the period. Therefore, a similar weather pattern is expected
throughout the short-term period. However, as winds pick up from 10
to 15 knots from the east to southeast, the focus of afternoon
convection will shift once again over west/northwest PR. In
addition, another band of moisture associated with distant Humberto
is still expected to increase shower activity across the USVI and
eastern PR between Monday night and Tuesday morning.

.LONG TERM...Wednesday through Sunday...

On Wednesday, at the surface, a high-pressure system will combine
with the extended influence of Hurricane Humberto, maintaining a
southeasterly wind flow across the region at least until early
Thursday. This surface pattern will favor a variable weather
regime with patches of fragmented moisture moving in and out of
the area. Precipitable water values on Wednesday are forecast to
range between 1.5 and 1.7, near the 25th percentile. From Thursday
into Friday, global model guidance continues to suggest an
interesting mix of patterns. At the surface, lapse rates between
850 and 700 mb indicate a stable pattern, with values dropping two
standard deviations below climatological normals. In contrast,
the mid-to-upper levels will exhibit increased lapse rates between
700 and 500 mb and colder 500 mb temperatures, ranging from -6 to
-7 degrees. Although this pattern supports afternoon convection,
models continue to show limited moisture with precipitable (PWAT)
of 1.50 inches. This pattern basically suggest a typical weather
pattern with localized showers, particularly across northwestern
Puerto Rico on Thursday.

On Friday into Sunday, veering surface winds are expected as the
tail of a tropical system moves eastward into the northeastern
Atlantic, weakening the surface high pressure diminish the
pressure gradient result in variable winds for the remainder of
the period. Therefore, on Friday, winds will become from the
north, inducing an advective pattern with sowers along northern
coastal areas in the morning and early evening hours. A rapidly
change will occur on Saturday, winds return from the east,
changing the weather pattern again. On Sunday, an increase in
tropical moisture with precipitable water values peaking up to 2
inches. So far today, Sunday looks like the wettest day of the
long term.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions are expected across all terminals during the
next 24 hours. However, iso TSRA/SHRA over central PR should cause
mostly VCTS across the PR terminals btw 28/17-21. Otherwise, VCSH
expected early in the fcst at TJPS/TISX/TIST. S-SW winds up to 13 kt
will continue mainly blo FL050.

&&

.MARINE...

Hazardous marine conditions continue due to a long-period
northeasterly swell generated by Major Hurricane Humberto, located
well to the north of the region. Seas will remain between 7 and 8
feet across the Atlantic waters and the Anegada Passage. A Small
Craft Advisory remains in effect through midnight. Improving
marine conditions are forecast from Monday into the workweek.
However, by midweek, model guidance suggests another northwesterly
swell will reach the local waters, deteriorating conditions once
again.

&&

.BEACH FORECAST...

Extremely hazardous coastal conditions are expected along the
northern and northeastern coasts, with breaking waves exceeding 10
feet. A High Surf Advisory is in effect until 6 PM AST for Culebra
and St. Croix. A High Risk of Rip Currents is also in effect.
Elsewhere, the rip current risk will remain moderate through
tomorrow. Improving coastal conditions are forecast from late
Monday into Tuesday. By midweek, another northwesterly swell is
expected to reach the region, worsening coastal conditions again.

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
518 AM AST Mon Sep 29 2025

.KEY MESSAGES...

* Another warm day is expected across the local islands, with heat
indexes exceeding 108 degrees Fahrenheit. Hence, a Heat Advisory
is in effect for the urban and coastal areas of Puerto Rico and
the U.S. Virgin Islands from 10 AM AST through 5 PM AST.

* For the U.S Virgin Islands, expect passing showers later tonight
across the islands.

* A large, long period northerly swell will promote hazardous
seas and life-threatening rip currents from late Thursday
through Sunday.

&&

.SHORT TERM...Today through Wednesday...

Isolated to scattered showers and brief isolated thunderstorms were
noted overnight across the Caribbean waters. Showers moved briefly
over the southern sections of the islands. Minimum temperatures
ranged from the upper-60s across the higher elevations to the upper
70s and low 80s across coastal areas. The wind was light from the
south to southeast.

Minor concentrations of Saharan dust will move over the islands
today. However, the precipitable water content will remain at normal
to above normal levels as Hurricane Humberto, well north of the
area, continues to pull tropical moisture in a deep southerly wind
flow over the eastern Caribbean. Shower activity is expected to peak
from late this afternoon through tonight across portions of the USVI
and east/southeast PR, with locally induced afternoon convection
expected over northwest PR. Trade winds will return by Tuesday, but
will turn once again from the south and become gentle to light on
Wednesday. Therefore, an elevated heat threat will persist across
the lower elevations of the islands. Maximum temperatures are
expected to reach the low to mid-90s each day across most coastal
counties. In terms of precipitation, a drier air mass is expected to
gradually fill from Tuesday into Wednesday, however, peaks on
moisture content are anticipated during the nighttime, favoring
showers across the windward areas of the islands. Also, locally
induced afternoon showers with isolated thunderstorms cannot be
ruled out over the NW quadrant of PR, particularly on Tuesday.

&&

.LONG TERM...Thursday through Monday...

Some changes were introduced to the long-term forecast. The wind
pattern will likely vary due to weather features inducing a col area
that should move over the CWA and promote lighter winds through at
least Sunday. A drier air mass filtering into the region and the
influence of a mid to upper level ridge will drop relative humidity
values and suppress deep convection activity, promoting stability
aloft. Based on the deterministic guidance of the GFS and ECMWF,
Precipitable Water (PWAT) values should stay between below-average
and seasonal values (1.5 - 1.7 inches, lower chance reaching 1.8
inches), but daytime heating combined with local effects could
lead to shower activity each day by midday into the afternoons.
Although deep convection activity may be limited, 500 mb
temperatures may cool and remain seasonal (-6 and -7 degrees
Celsius), increasing chances of isolated thunderstorms during the
afternoons. Due to winds becoming lighter, any shower activity
will likely remain stationary, increasing the flooding potential.
Hence, the flooding threat will remain limited to elevated over
the aforementioned areas. Moisture content will gradually increase
by Monday due to the approach of a vigorous tropical wave to the
CWA. Although there’s variability between ensemble members,
there’s a tendency for PWAT values to increase up to near above-
normal values (1.8 - 2.0 inches).

With well-above-normal 925 mb temperatures, slow SE-S winds, and
available moisture, heat indices are very likely to exceed 100
degrees Fahrenheit and reach Heat Advisory Criteria. Therefore, the
heat threat will remain elevated for the rest of the forecast
period.

&&

.AVIATION...

(06Z TAFS)

Mainly VFR conditions are expected to prevail across all terminals
during the next 24 hours. However, tempo MVFR conds are possible at
TJBQ btw 29/18-22 due to -TSRA/SHRA over NW PR. Elsewhere, brief
periods of -RA/VCSH expected at times. HZ due to Saharan dust will
increase over the local area, but VSBY will remain P6SM. SSE winds
up to 12 kt with sea breeze variations expected after 29/13z.

&&

.MARINE...

The long-period northerly swell from Major Hurricane Humberto
continues to diminish across the region. Moderate southeasterly to
easterly winds will continue for the next few days, becoming
gentle by the end of the workweek. A large northwesterly swell
will promote hazardous marine conditions by late Thursday night
through the upcoming weekend.

&&

.BEACH FORECAST...

The long-period northeasterly swell from Major Hurricane Humberto
continues to diminish across the region. Although the rip current
risk downgraded to moderate across the northern beaches of Puerto
Rico, including Culebra, and St. Thomas and St. John in the U.S.
Virgin Islands, beachgoers are urge to exercise caution. A large
northerly swell will promote hazardous beach conditions by late
Thursday night through the upcoming weekend.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
507 AM AST Tue Sep 30 2025

.KEY MESSAGES...

* Warmer conditions will persist for the next few days. A Heat
Advisory is in effect for all urban and coastal areas from 10
AM AST through 5 PM AST. Stay hydrated and avoid prolonged sun
exposure.

* For the U.S. Virgin Islands, shower activity will increase later
tonight, with limited flooding threat.

* A large, long-period swell arriving by late Thursday night will
promote hazardous marine and beach conditions across the
islands, persisting through the weekend.

&&

.SHORT TERM... Today through Thursday...

Passing showers embedded in the trade winds moved over portions of
the U.S. Virgin Islands, and over the eastern third and south coast
of Puerto Rico overnight. The Doppler radar estimated up to half an
inch of rain between Las Piedras and Humacao. Minimum temperatures
ranged once again from the upper-60s across the higher elevations to
the upper 70s and low 80s across coastal areas. The wind was from
the southeast at 10 mph or less. Showers today will be enhanced by a
band of precipitable water content of around 2.00 inches. However, a
drier air mass of around 1.50 inches will gradually filter over the
region from the southeast through Wednesday. Meanwhile, a low-level
trough is expected to develop over the eastern Caribbean late in the
period, enhancing moisture transport into the local area by
Thursday. Moderate southeast winds will prevail today, and become
lighter and more southerly on Wednesday, by Thursday winds will
abate furthermore and acquire a north-northeasterly component due to
the influence of the trough and a col area developing just north of
the region.

An elevated heat threat will persist across the lower elevations of
the islands through the shor-term period, with heat advisories
likely issued each day, with a possible extreme heat warning on
Wednesday due to the expected deep layered southerly flow. Across
the lower elevations of the islands, maximum temperatures are
expected to reach the low to mid-90s through at least Wednesday,
while the northerly component on Thursday may bring temperatures
down by a degree or two. Regardless, heat concerns will continue.

Although a drier air mass will filter over the region early in the
period, the 850-700mb and 700-500mb RH layers are expected to
increase from the 25th percentile today to the 50th percentile on
Wed/Thu. Also, in terms of stability, conditions are forecast to
become gradually more unstable at the mid-levels, as warmer lapse
rates and colder 500mb temperatures are anticipated on both days.
This is supported by a series of short-wave troughs moving along the
base of weak ridge north of the region. Therefore, afternoon
thunderstorms and showers are expected to develop each day, mainly
along portions of the Cordillera Central and in areas favored by the
weak steering winds, with the combination of intense heating,
lighter winds, and increasing instability favoring stronger
thunderstorms and higher rainfall accumulations on Wednesday and
Thursday. Across the USVI, the frequency of passing showers will
increase early in the period, but as winds decrease, the locally
induced late morning/early afternoon showers over land areas could
linger longer than usual.

&&

.LONG TERM... Friday through Tuesday...

Variable conditions are expected through the long-term forecast.
Winds will remain light and variable due to a col region
developing over the area, slightly increasing by Sunday, then
becoming lighter by the start of next workweek. As mentioned in
the previous discussion, a drier air mass is expected to filter
into the region due to the influence of a mid- level ridge that is
expected to linger northeast of the region. However, the latest
model guidance suggests that a mid-to- upper trough may move
south of the CWA by Friday and Saturday. The presence of this
feature is reflected in the projected 500 mb temperatures (between
-6.5 and -7.5 degrees Celsius), near below climatological
normals, enhancing the deep convection activity. As the
deterministic guidance of the GFS and ECMWF continues to suggest
low to seasonal PWAT values (1.6 - 1.8 inches), expect seasonal
weather conditions during the upcoming weekend, with isolated
showers moving over the local waters into windward sectors and
afternoon convection. Taking into consideration the wind speed,
there’s a high chance that any shower developing over the area
will stay stationary, meaning that the flood potential will be
more localized, particularly over the mountain ranges of Puerto
Rico. By early next week, a gradual increase in moisture content
and favorables conditions for deep convection are likely due to a
series of upper level troughs approaching the CWA. From the latest
model guidance, PWAT values should increase close to near above
normal values (1.8- 2.0 inches, low chance of reaching 2.2
inches). This could increase the frequency of showers and
thunderstorms moving across the local islands on Monday and
Tuesday, elevating flood potential. Given the expected conditions,
the flooding threat will remain from limited to elevated for the
rest of the forecast period.

The tendency of warmer conditions across the islands is expected
to continue due to above-normal temperatures, available moisture,
and light winds. Hence, the heat threat will remain limited to
elevated for the urban and coastal areas of Puerto Rico and the
U.S. Virgin Islands.

&&

.AVIATION...

(06Z TAFS)

Mainly VFR conditions are expected to prevail across all terminals
during the next 24 hours. However, tempo MVFR conds are possible at
TJBQ btw 30/16-22 due to TSRA/SHRA developing over NW PR. Elsewhere,
passing SHRA should cause mostly VCSH at times. Winds will continue
from the SE up to 16 kt blo 1000 ft. Sea breeze variations expected
mainly at TJBQ aft 30/13z.

&&

.MARINE...

Moderate southeasterly to easterly winds will continue for the next
few days, becoming gentle by Thursday. A large northerly swell will
promote hazardous marine conditions for small craft by late Thursday
night through the upcoming weekend.

&&

.BEACH FORECAST...

Today, the risk of rip current is expected to remain moderate for
the north-facing beaches of Puerto Rico, including Culebra, and
St. Thomas and St. John in the U.S. Virgin Islands. Although the
risk is moderate, life-threatning rip currents are still possible
along the surf zone, beachgoers should exercise caution.
The risk is expected to decrease on Wednesday, but a large, long-
period northerly swell arriving by late Thursday night will
promote life- threatening rip currents through at least Sunday.
Hence, beachgoers are urged to exercise caution and heed the
advice of the flag warning system.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Wed Oct 1 2025

.KEY MESSAGES...


* Hot temperatures today will promote hazardous heat conditions
across the islands. An Extreme Heat Warning is in effect for all
urban and coastal areas of the islands from 10 AM AST through 5
PM AST. Stay hydrated and avoid prolonged sun exposure.

* Showers and thunderstorms will increase the flooding and
lightning threat over interior and northern portions of Puerto
Rico this afternoon, while the U.S. Virgin Islands can expect
occasional passing showers throughout the day.

* A large, long-period northerly swell is expected by late
Thursday night, bringing hazardous marine and beach conditions
across the islands in the upcoming weekend.

&&

.SHORT TERM...Today through Friday...

Calm weather conditions prevailed overnight with a few showers
moving across the local waters, and some making their way inland
across the US Virgin Islands and windward locations in PR. Winds
were mainly from the southeast, calm to light and variable. In
general, skies were mostly clear with some clouds moving through the
Virgin Islands. Low temperatures ranged from the mid- to upper 70s
along the coastal areas to the mid- to upper 60s across the
mountains.

An easterly perturbation will increase the available moisture across
the islands today, which, combined with a light southeasterly wind
flow and the above-normal maximum temperatures, will result in
extreme heating across the urban and coastal locations in the US
Virgin Islands and Puerto Rico. As a result, an Extreme Heat Warning
is in effect from 10 AM AST to 5 PM AST. The excessive heating will
then combine with the local effects, giving place to one or two
strong afternoon thunderstorms across the interior and northern
portions of PR. These thunderstorms will result in frequent cloud-to-
ground lightning, downpours, and gusty winds. The afternoon
convection is expected to dissipate by evening, leaving mostly clear
skies and calm weather conditions for the islanders. The weak
steering wind flow will allow the thunderstorms to remain almost
stationary, thus creating a slight risk of flooding rains,
especially if forming over areas with poorly drained conditions.

A similar weather pattern will prevail in the short term, consisting
of warm to hot indices during the maximum heating time of the day,
followed by afternoon convection across portions of PR, and a few
passing showers across the US Virgin Islands and windward locations
of PR overnight and early in the morning.

&&

.LONG TERM...Saturday through Wednesday...

The long-term forecast remains on track, with a transition to
wetter and unstable conditions for the first part of the
workweek. A tropical wave over Central Atlantic approaching the
Caribbean Basin is expected to arrive by Saturday, increasing
shower activity across the local islands but remaining limited due
drier air in the 700 - 300 mb layer. The latest model guidance
continues to suggest the approach of upper- level troughs over the
CWA by Saturday and lingering for the remainder of the period.
From the latest deterministic guidance of the GFS and ECMWF,
Precipitable Water (PWAT) values may increase to above normal
values (2.0 - 2.2 inches) by Monday through Wednesday.
Additionally, this could push relative humidities in the lower and
mid-levels to well above normal (around 80%). The presence of
these troughs should promote colder 500 mb temperatures (-7 and -8
degrees Celsius), favorable for deep convection activity. The
Galvez-Davison Index (GDI) also suggests the potential of isolated
to scattered thunderstorms on Monday and Tuesday, increasing the
lightning threat. Another factor that may influence the shower and
thunderstorm activity is that winds will once again drop by late
Monday night, meaning that any convection activity could remain
stationary and increase the flooding threat as well. At the
moment, expect an increase in shower and thunderstorm activity,
particularly over windward sections of the islands and deep
convection activity affecting mostly the mountain ranges of Puerto
Rico, gradually improving by Wednesday. Although the flooding and
lightning threat will remain limited to elevated during the long-
term forecast, confidence remains low due to variability between
ensemble members.

&&

.AVIATION...
(06z TAF)

VFR conditions will prevail today for all TAFs. However, a few TSRA
will develop during the afternoon (between 01/15-22z), which could
impact JSJ/IST/ISX or JBQ, creating brief MVFR conditions if those
TSRA move over them. Winds will prevail mainly from the SE-ESE at 5-
10 kt, with sea breeze variations after 01/13z, and gusty winds near
TSRA. Winds will turn calm to light and VRB aft 01/23z.

&&

.MARINE...

Light to gentle southeasterly winds will continue for the next few
days as a col area approaches the region. A tropical wave approaching
the Caribbean Basin should increase shower and thunderstorm activity
across the regional waters and local passages by Saturday. A large
long-period swell will promote hazardous marine conditions for small
craft by late Thursday night through the upcoming weekend.

&&

.BEACH FORECAST...

As anticipated, the risk of rip current became low for all beaches
of Puerto Rico and the U.S. Virgin Islands. Nevertheless,
a large, long-period swell is anticipated to arrive by late
Thursday night and persisting through at least Sunday. Life-
threatening rip currents are expected mainly along north-facing
beaches of Puerto Rico and the northern U.S. Virgin Islands. This
swell could also increase high surf potential as well, hence,
beachgoers should continue monitoring the beach forecast and heed
the advice of the flag warning system. Additionally, they should
stay weather alert due to the potential of showers and
thunderstorms moving over the western and northwestern coastal
areas of Puerto Rico in the afternoon.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
452 AM AST Thu Oct 2 2025

.KEY MESSAGES...

* Warmer conditions will continue today, particularly across the
urban and coastal areas of Puerto Rico and the U.S. Virgin
Islands. A Heat Advisory is in effect from 10 AM through 5 PM
AST. Stay hydrated and avoid prolonged sun exposure.

* Showers and thunderstorms along interior and northern portions
of Puerto Rico will increase flooding and lightning risk this
afternoon.

* Once again, occasional passing showers are expected across the
U.S. Virgin Islands throughout the day.

* A long-period swell will arriving late tonight will deteriorate
marine and coastal conditions through early next week. Small
Craft Advisories are in effect from midnight tonight for the
Atlantic offshore waters and from noon Friday for the Atlantic
coastal waters and the Mona Passage.


&&

.SHORT TERM... Today through Saturday...

Calm weather conditions prevailed overnight with little to no rain
for the US Virgin Islands and windward locations in PR. Winds were
calm to light and variable, influenced by a land breeze. In general,
skies were mostly clear with some clouds moving through the Virgin
Islands. Nighttime cooling allowed the low temperatures to drop from
the mid- to upper 70s in coastal areas to the mid- to upper 60s
across the mountains.

A col area near the region will continue to promote light
southeasterly winds today and tomorrow. Moisture content is expected
to remain near or below normal through Friday. However, the
available moisture, combined with above-normal expected maximum
temperatures, will result in warm to hot heat indices during the
peak of daily heating this afternoon. Thus, a Heat Advisory is once
again in effect for coastal and urban locations in the US Virgin
Islands and Puerto Rico. Excessive heating, enhanced by local
effects and variations in sea breezes, will result in strong
thunderstorms across the interior and northern regions of PR. This
activity is expected to result in cloud-to-ground lightning, heavy
rain, and strong winds. Due to weak steering winds, expect some
thunderstorms to remain almost stationary, leading to a heightened
risk of flooding in poorly drained areas. Be prepared. These storms
will likely clear by evening, resulting in calm weather. A similar
weather pattern is expected to repeat on Friday.

A long-period north-northwesterly swell will impact the Atlantic
coastline, producing dangerous breaking waves and life-threatening
rip currents starting late Thursday night or early Friday morning.
It's essential to acknowledge the significant threat this poses to
beachgoers who go to the north-facing beaches in Puerto Rico and the
northern US Virgin Islands. Avoid becoming just another statistic.

For Saturday, a weak tropical wave moving across the Caribbean Sea
and a frontal boundary lingering north of the islands over the
Atlantic Ocean will increase the moisture content somewhat, as well
as the potential for more frequent passing showers followed by
isolated to scattered thunderstorms during the afternoon.

&&

.LONG TERM... Sunday through Thursday...

No major changes were introduced to the long-term forecast. A
transition to an unstable and wetter pattern is still anticipated by
the beginning of the workweek, with gradual improvement by
Wednesday. Global models continue to suggest the approach of an
upper-level trough into the CWA by Sunday night. From the
deterministic guidance of the GFS and ECMWF, the tendency towards
wetter conditions is increasing, as Precipitable Water (PWAT) values
may range between 2.0 and 2.2 inches, above the climatological
normal. The latest model solutions also suggest a rise in relative
humidity content in the low and mid levels as well (> 60 %, up to 80
- 90%) during Monday and Tuesday. In terms of instability, the
presence of this upper feature should bring colder than normal 500
mb temperatures (down to -8 degrees Celsius), favorable for the
development of strong thunderstorms. The latest Galvez-Davison Index
(GDI) tool keeps suggesting the potential of isolated to scattered
thunderstorms across the CWA, higher on Monday and Tuesday. As
mentioned in the previous discussion, winds will become lighter late
Monday night and Tuesday, meaning that there’s a high chance of
stationary showers and thunderstorms. Given the expected conditions,
the potential of flooding and lightning will increase, particularly
over mountain ranges and eastern Puerto Rico, including Vieques and
Culebra, and the U.S. Virgin Islands.

Conditions should gradually improve by Wednesday, as a drier air
mass may filter into the region. Although PWAT may drop to seasonal
values (1.5 - 1.7 inches), the available moisture combined with
diurnal heating and local effects could trigger convection activity
in the afternoon, affecting mainly portions of interior and western
Puerto Rico, including the San Juan Metropolitan Area. Nevertheless,
the likeliest scenario could be mostly ponding of water over
roadways, urban, and poorly drained areas.

The National Hurricane Center is monitoring a tropical wave expected
to move off the coast of Africa in the next few days, with a 20%
chance of cyclonic formation in the next 7 days. The latest model
solutions suggest an increase in moisture content due to this
tropical wave approaching the Caribbean Basin by late Thursday
night, but the variability between them is high, introducing
uncertainty to the forecast. Hence, we’ll keep monitoring the
development of this system.

&&

.AVIATION...

(TAFs 06z)

VFR conditions will prevail today for all TAFs. However, a few TSRA
will develop during the afternoon, between 02/15-22z, which could
impact JSJ or JBQ, creating brief MVFR conditions if those TSRA move
over them. Winds will prevail mainly from the S-SE at 5-10 kt, with
sea breeze variations after 02/13z, and gusty winds near TSRA. Winds
will turn calm to light and VRB aft 02/23z.

&&

.MARINE...

A col near the region will promote a light to gentle southerly wind
flow across the islands through Friday. A long-period north to
northwesterly swell will begin to spread across the local Atlantic
waters late tonight and into Friday, deteriorating marine and coastal
conditions through early next week. Additionally, a weak tropical
wave is expected to move over the Lesser Antilles by Friday, moving
near the islands by Saturday. At the same time, a frontal boundary
will remain positioned to the north over the Atlantic.

&&

.BEACH FORECAST...

No major changes were introduced to the beach forecast. As
anticipated, the rip current risk increased to moderate mainly for
the northern beaches of Puerto Rico, including Culebra. As
mentioned in previous discussions, a long-period swell will arrive
late tonight, bringing hazardous beach conditions through at
least early next week. Life-threatening rip currents are expected
along the north- facing beaches of Puerto Rico, including Vieques
and Culebra, and the northern U.S. Virgin Islands, spreading over
west-facing beaches of Puerto Rico and St. Croix in the U.S.
Virgin Islands during the weekend. Additionally, the potential of
High Surf conditions is increasing due to high chance of breaking
waves above 10 feet. Therefore, citizens and visitors are
encouraged to continue monitoring the beach forecast and heed the
advice of the flag warning system. Regarding the weather forecast,
beachgoers should stay weather alert due to the potential of
showers and thunderstorms near and/or approaching the beach zone,
particularly over the western and northeastern coastal areas of
Puerto Rico.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
502 AM AST Fri Oct 3 2025

.KEY MESSAGES...

* A strong, long-period northerly swell will create hazardous
marine and beach conditions across the islands through at least
early next week.

* Showers and thunderstorms in the afternoon over will enhance the
flooding and lightning threat for the next few days. If thunder
roars, stay indoors.

* Occasional passing showers are expected across the U.S. Virgin
Islands tonight through early Saturday.

&&

.SHORT TERM...Today through Sunday...

Tranquil conditions prevailed during the night hours across Puerto
Rico and the Virgin Islands. Some showers managed to form in the
local waters, but otherwise, skies were mostly clear.

A series of deep-layered longwave troughs are maintaining very weak
winds across the islands. In fact, the steering flow is expected to
be from the northeast at 4 to 8 kts today, from the southeast at 4
to 10 knots on Saturday, and also from the southeast on Sunday, but
a little stronger, with speeds around 10 kts. There is also a weak
low to mid level ridge centered west of Puerto Rico. This feature
will keep moisture below normal for today. Even though the
atmosphere is not prime for widespread significant rainfall, diurnal
heating will still trigger showers and isolated thunderstorms across
the Cordillera Central in Puerto Rico. Since winds are light, some
localized urban flood could develop, while isolated lightning
strikes cannot be ruled out. In the vicinity of the Virgin Islands,
some showers are expected to develop too, although mostly staying
over the local waters.

On Saturday, an upper level low will move over Hispaniola, then
advancing toward the local islands by Sunday. This feature will
induce some showers over the local waters, potentially reaching the
Virgin Islands and portions of eastern Puerto Rico. It is worth
mentioning that moisture at the mid levels will remain below normal,
although it will increase a little at the surface. Nevertheless,
these conditions should still support afternoon showers and isolated
thunderstorms each afternoon. On Saturday, the focus of the rain
should be along the Cordillera Central. On Sunday, the western
interior and northwestern portions of Puerto Rico are favored. These
areas will likely experience localized urban and small stream flood.
Thunderstorms are not expected to be too widespread, but some
lightning strikes are still anticipated each afternoon.

&&

.LONG TERM...Monday through Friday...

The long-term forecast remains on track, with a wet and unstable
pattern for the beginning of the workweek. Recent model guidance
indicates an upper-level cutoff low over the region, which is
expected to gradually move south and migrate westward by the end of
the period. As mentioned in previous discussions, the deterministic
guidance from the GFS and ECMWF keeps suggesting an increase in
moisture content, with PWAT values likely to range between 2.0 - 2.2
inches (up to or above climatological values). Additionally,
ensemble members continue to suggest a wetter and unstable pattern
across the CWA on Monday and Tuesday, with Monday through early
Tuesday being the wettest period. A difference between the previous
solution runs is related to instability, as 500 mb temperatures look
slightly warmer (between -6.5 to -7.0 degrees Celsius).
Nevertheless, the latest Galvez-Davison Index (GDI) solution keeps
suggesting the potential of isolated to scattered thunderstorms
across the CWA, but not a widespread scenario. Another factor that
may influence the weather pattern is the low-level wind speed,
expected to increase and remain E-SE during that period. The most
likely scenario remains the same, with an increase in shower and
thunderstorm activity across the windward sections of Puerto Rico
and the U.S. Virgin Islands throughout Monday and early Tuesday. The
deeper convection should be expected in the afternoon, particularly
over the mountain ranges and western/northwestern Puerto Rico. Given
the expected conditions, the flood threat will remain limited to
elevated, and a limited lightning threat is also expected across the
aforementioned areas. The gradual improvement of weather conditions
is still anticipated by Wednesday, as a drier air mass filtering
into the region will promote stability aloft. Nevertheless, this
pattern may increase the heat threat, becoming elevated to
significant on Wednesday and Thursday.

The National Hurricane Center is monitoring a tropical wave expected
to move off the coast of Africa in the next few days, with a 20%
chance of cyclonic formation for the next 7 days. The latest model
solutions continue to suggest an increase in moisture content by the
end of the forecast period due to this tropical wave approaching the
Caribbean Basin, but the variability between them continues high in
terms of trajectory and intensity. Hence, the uncertainty remains
high for Friday’s forecast.

&&

.AVIATION...

(06Z TAFS)

Mainly VFR conditions are expected to
prevail. SHRA is expected after 17Z along the Cordillera Central,
causing mountain obscuration. VCTS are also expected for TJPS
after 17Z, with brief periods of reduced VIS and low ceilings.
SHRA in the vicinity of the USVI should cause little to no impact
to operations. Winds are light, coming from the NE and below 10
knots.

&&

.MARINE...

A col near the region will promote a light to gentle variable wind
flow across the islands for the next few days. A long- period north
to northwesterly swell arriving into the region will spread across
the local Atlantic waters and passages today into the weekend,
deteriorating marine and coastal conditions through early next week.
Small Craft Advisories are in effect for the Atlantic offshore and
coastal waters, including the Mona and Anegada Passages.

&&

.BEACH FORECAST...

A strong, long-period northerly swell arriving into the region
will create hazardous beach conditions through at least early next
week. Hence, the high rip current risk is in effect for exposed
coasts to the Atlantic, including western to northeastern Puerto
Rico, Culebra, Vieques, St. Thomas and St. John through at least
Monday night. As mentioned in previous discussions, the potential
of breaking waves exceeding High Surf Criteria is very high,
resulting in localized beach/dune erosion and dangerous swimming
conditions. Therefore, a High Surf Advisory is in effect for the
exposed beaches to the Atlantic as well, from northwestern to
northeastern Puerto Rico, Culebra, and St. Thomas and St. John
through Monday morning. Citizens and visitors are encouraged to
continue monitoring the beach forecast and heed the advice of the
flag warning system. Beachgoers, do not risk your life, is better
to stay out of the water!

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
306 AM AST Sat Oct 4 2025

.KEY MESSAGES...

* A strong, long-period northerly swell will continue to produce
hazardous marine and beach conditions across the islands through
at least early next week. A Coastal Flood Advisory, Small Craft
Advisories, Rip Current Statements, and High Surf Advisories
remain in effect.

* Showers and thunderstorm activity is expected this afternoon
over portions of central and northwestern Puerto Rico, enhancing
the flooding and lightning threat across the area. If thunder
roars, stay indoors.

* Across the U.S. Virgin Islands, passing showers will move
occasionally over the region through the afternoon hours.

&&

.SHORT TERM...Today through Monday...

Conditions were mostly tranquil during the night hours. Some showers
manage to form in the vicinity of the Virgin Islands and eastern
Puerto Rico, but accumulation over land was very little. Skies were
mostly clear.

The trade winds are still weak, with a steering flow now shifting
from the southeast and at 4 to 8 kts. The winds will increase just a
bit on Sunday and Monday, but still around 8 to 11 kts. At the upper
levels, an upper level low will maintain some instability in the
area, and this feature will linger into early in the workweek.
Moisture is a little below normal today, but it is expected to
increase toward more normal values on Sunday, and even a little more
on Monday due to an approaching tropical wave. In general, the
pattern will favor afternoon showers along the Cordillera Central
and western Puerto Rico today and Monday. Showers could also stream
from El Yunque toward the San Juan metro area. The risk of flooding
will be elevated with a medium chance of these areas experiencing
urban and small stream flooding. Some lightning strikes will be
possible too. In the Virgin Islands, as well as some sections of
eastern Puerto Rico, passing showers will be on the increase by late
Sunday and Monday. While flooding is not really anticipated, ponding
of water and wet roads can still be expected.

.LONG TERM...Tuesday through Saturday...

The forecast period starts with a wet and unstable pattern due to
the influence of an upper-level low over the region. By Tuesday, the
convergence of this low with an approaching weak tropical wave is
expected to enhance the potential of convective activity,
specifically showers and thunderstorms, across the U.S. Virgin
Islands and Puerto Rico. High atmospheric moisture will sustain the
showers and thunderstorm activity through Tuesday evening, with
PWAT content near-to-above-normal (2.00 to 2.25 inches). A
noticeable change is anticipated for Wednesday, as a departing
upper-level low allows drier air to move in, causing PWAT values
to fall to the 1.50 to 1.75 inch range. Looking ahead to Thursday,
local conditions will become dependent on the evolution of a
tropical wave currently near the coast of Africa.

Regarding the potential system, the National Hurricane Center (NHC)
has given this wave a medium formation chance (50%) over the next 7
days. Although the latest model guidance indicate increasing
moisture by the weekend, the system's eventual trajectory and
intensity remain highly uncertain. All residents and visitors must
continue to track the progress of this system as it moves westwards
over the Atlantic Ocean.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions expected to prevail through the forecast
period. After 17-19Z, SHRA and TSRA are expected to develop along
the Cordillera Central. These showers should reach the PR terminals,
causing periods of reduced VIS and low ceilings. VCSH are expected
for VI terminals, but impacts to operations are expected to be
minimal. Winds are light, out of the E to ESE at 2-8 kts.

&&

.MARINE...

A col near the region will promote a light to gentle variable wind
flow across the islands for the next few days. A long-period north
to northwesterly swell will spread across the local Atlantic waters
and passages through early next week, deteriorating marine and
coastal conditions through early next week. A tropical wave will
approach the region by Monday, increasing the frequency of
showers.

&&

.BEACH FORECAST...

A strong, long-period northerly swell will continue to produce
hazardous beach conditions through at least Monday night along the
Atlantic exposed beaches, including from western to northeastern
Puerto Rico, Culebra, Vieques, and the U.S. Virgin Islands. As a
result, there is a high risk of life-threatening rip currents in
the aforementioned areas.

A Coastal Flood Advisory is in effect for all the Atlantic exposed
beaches of the islands through Saturday evening. In addition, a
High Surf Advisory is in effect for these areas through Monday
morning. Please refer to our Coastal Hazard Message (CFWSJU) for
additional details. Residents and visitors are urged to monitor
the beach forecast and follow the beach flag warning system.
Beachgoers, do not risk your life, it's better to stay out of the
water throughout the upcoming weekend!

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
308 AM AST Sun Oct 5 2025

.KEY MESSAGES...

* A strong, long-period northerly swell will continue to produce
hazardous beach and marine conditions through at least early
next week. A Coastal Flood Warning, High Surf Warning, Rip
Current Statements, and Small Craft Advisories remain in effect.

* Rounds of showers and thunderstorms will enhance the flooding
and lightning threat across from el Yunque into the metropolitan
area and from the interior to western sectors of Puerto Rico. If
thunder roars, stay indoors.

* Across the U.S. Virgin Islands, passing showers and a few
thunderstorms are expected throughout the period.

&&

.SHORT TERM...SHORT-TERM...Today through Monday...

The most recent satellite derived precipitable water imagery shows
that moisture has rise into the islands, with values closer to 1.9
inches over the Virgin Islands and the local waters. This moisture
is mostly focused near the surface and in the upper levels, but the
mid levels remains drier than normal. The moisture in the upper
levels is due to an upper level low centered just west of Puerto
Rico. The low induced some showers and thunderstorms near St. Thomas
and St. Croix, but rainfall accumulations were not too significant.

For today, a long wave trough well north of the region maintain the
trade winds very week, out of the east-southeast, and below 8 knots.
The upper level low will increase instability aloft a little, and
will allow for a modest increase in moisture in the mid-levels. As a
result, another active afternoon is anticipated for the interior and
western Puerto Rico, with some showers and thunderstorms also
reaching portions of the San Juan metro area. These rains will
increase the risk of urban and small stream flooding, as well as
lightning strikes in the vicinity of the thunderstorms. The Virgin
Islands and eastern Puerto Rico will also observe passing showers
and thunderstorms. Even though flooding is not anticipated here,
ponding of water and wet roads can be expected, as well as
occasional lightning strikes.

For Monday and Tuesday, the islands will remain under the influence
of the upper level low. Winds will remain very light, out of the
northeast on Monday and out of the southeast on Tuesday. Moisture
will also increase as a tropical wave approaches the region. Again,
the pattern will favor increasing showers over portions of the
Virgin Islands and eastern Puerto Rico throughout the day, but the
strongest activity will be focused for the interior and western
Puerto Rico. Some of these storms will also stream from El Yunque
toward the San Juan metro area. The risk of flooding will remain on
the medium side, meaning that it should be mostly urban and small
stream flooding, although isolated flash flooding cannot be ruled
out.

Temperatures will be on the increase too. Urban and coastal areas,
as well as valleys in the mountain will experience heat indices
above 102 degrees, and locally reaching levels where those sensitive
to heat and without adequate cooling or hydration may be affected.


.LONG TERM....LONG TERM...Wednesday through Sunday...

An upper-level low northeast of the region will begin to move away
from the area by Wednesday. Subsequently, a mid-to-upper level ridge
will take place across the area, promoting drier air intrusion and
stable conditions aloft from Wednesday into Thursday. The latest
precipitable water (PWAT) analysis indicates normal climatological
values throughout much of the period. Additionally, the 500 mb
temperatures will also remain within normal values (between −6 to −7
degrees Celsius) during the period.

By Thursday, moisture will slightly increase with the arrival of an
atmospheric disturbance, promoting showers and isolated
thunderstorms across the area. Under this moist pattern and with
southeasterly winds, the shower activity will be expected toward the
central and northwestern municipalities of Puerto Rico. For the U.S.
Virgin Islands, showery weather is anticipated each morning across
the islands. Winds will prevail mostly from the southeast in
response to a surface high pressure in the central Atlantic.
However, by the end of the period, the steering winds will depend on
the potential development of a tropical wave near the islands.

The second half of the forecast will depend on the development of a
broad tropical wave located south of the Cabo Verde Islands. The
National Hurricane Center (NHC) is monitoring the aforementioned
wave with a low formation chance (30%) in the next 48 hours, and a
medium formation chance (60%) in the next 7 days. The latest model
guidance continues to suggest an increase in moisture content
associated with this system from Friday onwards. At this time, there
is high uncertainty in terms of the trajectory and intensity of this
wave. Residents and visitors are urged to continue monitoring the
progress of this system as it moves over the Atlantic Ocean.

&&

.AVIATION...
(06Z TAF)

Mainly VFR conditions are expected to prevail through the forecast
period. SHRA and TSRA are expected to reach the USVI and TJSJ
terminals through the day, with brief periods of reduced VIS and low
ceilings. After 17Z, widespread SHRA and TSRA are anticipated for
the Cordillera Central and western PR. Impacts are expected to be
more significant for the TJBQ terminal, until around 22Z. Winds will
be from the ESE below at 6-11 kts.

&&

.MARINE...

A col near the region will promote a light to gentle variable wind
flow across the islands today. A long-period north to northwesterly
swell will spread across the local Atlantic waters and passages
through early next week, deteriorating marine and coastal conditions
through the upcoming workweek. A tropical wave will approach the
region by Monday, increasing the frequency of showers.

&&

.BEACH FORECAST...

A strong, long-period northerly swell will continue to produce
hazardous beach conditions through at least Monday night along the
Atlantic exposed beaches, including from western to northeastern
Puerto Rico, Culebra, Vieques, and the U.S. Virgin Islands. As a
result, the high risk of life-threatening rip currents continues
in the aforementioned areas.

The Coastal Flood Warning and High Surf Warning continues in
effect due to the latest buoy observations with the combination
of the next expected high tides. The Coastal Flood Warning will be
in effect at least until 6 PM AST Sunday for the northern and
eastern coast of Puerto Rico, and the High Surf Warning until 6 PM
AST Monday, for the same areas and also including Culebra and St.
Thomas. Potential impacts include: Large breaking waves up to 14
to 18 feet and occasionally higher in some isolated areas.
Widespread coastal flooding, highest risk at high tide.
Additionally, significant beach erosion, dangerous surf, and life-
threatening rip currents. Please refer to our Coastal Hazard
Message (CFWSJU) for additional details. Residents and visitors
are urged to monitor the beach forecast and follow the beach flag
warning system. Beachgoers, do not risk your life, it's better to
stay out of the water throughout the weekend!

Next high tides: La Puntilla, San Juan at 7:03 AM AST (1.5 ft);
Arecibo at 6:38 AM AST (1.7 ft), and Crash Boat, Aguadilla at 6:30
AM AST (1.5 ft).

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST Mon Oct 6 2025

.KEY MESSAGES...

* A strong, long-period northeasterly swell will continue to
produce hazardous beach and marine conditions through at least
Tuesday afternoon.

* Increasing moisture from a tropical wave approaching the
northeastern Caribbean region will enhance shower and
thunderstorm activity across the local islands today and Tuesday.
There is a limited to elevated flood risk, particularly for
central and southern Puerto Rico.

* Across the U.S. Virgin Islands, passing showers and isolated
thunderstorms are expected with a limited flood risk today.

&&

.SHORT TERM...Today through Wednesday...

Current satellite derived precipitable water (PWAT) values indicate
generally normal values over the islands ranging from 1.75 to 2.10
inches. Since midnight, showers and isolated t-storms have reached
windward sectors of the islands under northeasterly steering flow
with radar estimated accumulations (as of 4 AM) observed over north-
central, eastern, and southeastern Puerto Rico, as well as over
Culebra, Vieques, St. Thomas and St. Croix. As of 4 AM, the highest
radar estimated accumulations over PR where around three quarters of
an inch over isolated sectors of Canovanas, Carolina, Patillas,
Maunabo and Yabucoa. As of 4 AM, the highest radar estimated
accumulations over the USVI where around 0.19 in over northeastern
St. Thomas. Fog was also detected over areas of the interior. Lows
where in the mid 70s to low 80s over coastal and urban areas of the
islands and in the low 60s over interior Puerto Rico.

The main features during this period will be an upper level low,
centered southwest of Puerto Rico, and a tropical wave, soon moving
over the Lesser Antilles. 500 mb temperatures are forecast to remain
at normal values at around -6 to -5 degrees Celsius. 700 mb to
500 mb lapse rates are forecast at normal to slightly above normal
values 5.7 to 6.3 degrees C/km. PWAT values will also remain at
normal to above normal (peaking around 2.1 in when the bulk of the
moisture plume from the wave moves over the islands) values, with
the lowest values forecast for Wednesday. The upper level low
will gradually move northward as the period progresses, late in
the period an upper level ridge is forecast to develop.
Northeasterly steering flow is forecast to veer and become more
easterly during the morning but the approach of the tropical wave
will again promote northeasterly steering flow late afternoon. As
the wave moves over the region overnight into tomorrow,
southeasterly steering flow will dominate for the rest of the
period. With the above mentioned features and values, as well as
with diurnal heating, sea breeze convergence and orographic
effects, active afternoons are expected today and Tuesday. A
limited to elevated flooding risk will persist each day with
convective showers and thunderstorms forecast for interior to
western, south and southwestern Puerto Rico this afternoon and for
Tuesday, for interior to western, northern and northwestern
Puerto Rico. Lines of showers are also possible downwind of the
local islands and El Yunque. Advective shower and isolated t-storm
activity is also forecast to affect windward sectors of the
islands during the morning and overnight hours as the nearby above
mentioned features provide enough instability and moisture. Low
concentrations of Saharan Dust will also move over the islands
today. Drier and somewhat more stable conditions are forecast for
Wednesday but diurnal heating, sea breeze convergence and local
effects will promote convection over mainly the northwestern
quadrant of PR during the afternoon. Hazards include frequent
lightning, ponding of water on roadways, urban and small- stream
flooding and possible isolated flash floods. Additionally, gusty
winds, small hail, and possible isolated funnel clouds are also
hazards during the short term period, especially on Tuesday. 925
mb temperatures will be normal to slightly above normal today but
increase to above normal values Tuesday and Wednesday under
southeasterly flow.

.LONG TERM...Thursday through Monday...

The long-term forecast depends on the development of a tropical wave
located southwest of the Cabo Verde Islands. The National Hurricane
Center (NHC) continues to monitor this wave, assigning it a high
(70%) chance of tropical cyclone formation within the next seven
days as it moves quickly across the central Atlantic.

Regardless of its development, the latest model guidance suggests a
track that will pass to the northeast of the Lesser Antilles by the
end of the workweek. Moisture associated with this system is
expected to reach the northeast Caribbean by early Friday,
increasing the potential for showers and thunderstorms across the
regional waters and portions of Puerto Rico and the U.S. Virgin
Islands.

By Saturday, as the system moves just north of the area, winds will
shift from the south. This southerly flow will steer convection
inland, focusing showers and thunderstorms over the northern
portions of Puerto Rico and the U.S. Virgin Islands. By Monday,
winds will become from the southeast as the trailing edge of the
system moves over the islands, further enhancing the potential for
showers and thunderstorms across Puerto Rico and the U.S. Virgin
Islands.

Uncertainty remains high regarding specific rainfall amounts and any
potential local threats. Residents and visitors are therefore urged
to monitor the progress of this system closely over the coming days.


&&

.AVIATION...
(06Z TAFs)

Mainly VFR conditions expected to prevail. During the period, SHRA
and TSRA are forecast to continue reaching or moving close to
TJSJ/TIST/TISX, and possibly TJBQ, under ENE steering flow. These
can produce brief periods of reduced visibilities and lower
ceilings. After around 17Z, SHRA/TSRA over the Cordillera will
spread mainly to western/south/southwestern PR. Although VCTS
continues for TJSJ/TJBQ, impacts are expected to be more significant
at TJPS. ENE to E winds at around 6-13 kts, decreasing after 6/23Z.

&&

.MARINE...

A long-period northeasterly swell will continue to spread across the
local Atlantic waters and passages through at least Tuesday.
Therefore, marine and coastal conditions will continue deteriorated
through mid-week. A tropical wave will approach the region today,
increasing the frequency of showers and thunderstorms across the
regional waters, particularly during the afternoon hours.

&&

.BEACH FORECAST...

The strong long-period northeasterly swell will continue to produce
hazardous beach conditions through at least Tuesday evening along
the Atlantic exposed beaches. As a result, the high risk of life-
threatening rip currents continues through at least Tuesday
afternoon and early evening across western, northern, eastern
coasts of Puerto Rico, Culebra, Vieques and U.S. Virgin Islands.

A High Surf Advisory remains in effect for mentioned areas of
Puerto Rico, Culebra and U.S. Virgin Islands through at least 6 AM
AST Tuesday. Potential impacts include: high waves that can wash
over jetties and sweep people and pets onto jagged rocks. Large
breaking waves will result in localized beach/dune structure
erosion and dangerous swimming conditions, as well as minor
coastal flooding in the most vulnerable areas.

Residents and visitors are strongly encouraged to keep an eye on
the beach forecast and follow the beach flag warning system.
Beachgoers, don’t take unnecessary risks, it's safest to stay out
of the water at least through next Tuesday! For more information
about each hazard, please consult our Coastal Hazard Message
(CFWSJU).

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
524 AM AST Tue Oct 7 2025

.KEY MESSAGES...

* A tropical wave will continue to move over region today,
enhancing the shower and thunderstorm activity across the local
islands. There is a limited to elevated flood risk, particularly
across central, northwestern, and northeastern (including the
San Juan metro area) Puerto Rico.

* Travel disruptions, frequent lightning, and urban or small-
stream flooding possible with isolated flash flooding cannot
ruled out.

* Increased risk of heat-related illness especially for vulnerable
groups and outdoor workers. Heat impacts will rise on Wednesday
and persist through the weekend with greatest effects in
coastal and urban areas.

* For the US Virgin Islands, minor flooding and lightning possible
today. Elevated heat will affect outdoor activities every day.

&&

.SHORT TERM...Today through Thursday...

Moisture from a tropical wave has increased precipitable water
values (PWAT) to high end normal to above normal values over the
islands. Current satellite derived PWAT values indicate around 1.90
to 2.30 inches over the islands. Since midnight, showers and
isolated t-storms have reached windward sectors of the islands under
a northeasterly steering flow. Radar estimated accumulations (as of
4 AM) were observed over eastern and northern Puerto Rico (highest
estimated accumulation was 0.45 in over Loiza), as well as Culebra.
Showers and t-storms have mostly remained in the vicinity of the
USVI, with very low accumulations over isolated coastal areas. Lows
were in the mid to upper 70s over coastal and urban areas of Puerto
Rico and in the low 60s over interior Puerto Rico. Lows were in the
upper 70s to low 80s over the USVI, Culebra and Vieques.

An upper level low is centered southwest of Puerto Rico and a
tropical wave will continue to move over the region today.
Northeasterly steering flow is forecast to veer and become
southeasterly by this morning as the axis of the wave moves over the
area. Southeasterly steering flow will dominate for the rest of the
period. 500 mb temperatures are forecast to remain at normal values
at around -7.1 to -6.5 degrees Celsius, before becoming even colder
during the long term period. 700 mb to 500 mb lapse rates are
forecast at normal to above normal values 5.7 to 6.4 degrees C/km
(peaking today). PWAT values will also remain generally above 2
inches today and Thursday, with the lowest values forecast for
Wednesday. The upper level low will gradually move northward today
and tomorrow, as an upper level ridge is forecast to develop. With
the above mentioned features and values, as well as with diurnal
heating, sea breeze convergence and orographic effects, an active
afternoon is expected today. A limited to elevated flooding risk
will persist with convective showers and thunderstorms forecast for
interior to western, northern and northwestern Puerto Rico today,
with lines of convection also possible downwind of the local islands
and El Yunque. Advective shower and isolated t-storm activity is
also forecast to affect windward sectors of the islands during the
morning and overnight hours as the nearby above mentioned features
provide enough instability and moisture. Hazards include frequent
lightning, ponding of water on roadways, urban and small- stream
flooding and possible isolated flash floods. 925 mb temperatures
will be normal to above normal during the period, possibly tampered
by expected weather today but southeasterly flow will make this
hazard more pronounced for the rest of the period under
southeasterly flow. Lower PWAT values and ridging aloft can limit
afternoon convection on Wednesday but diurnal heating, sea breeze
convergence and local effects will promote convection over mainly
the northwestern quadrant of PR. Moisture is forecast to increase
once again on Thursday, aiding in afternoon convection under
southeasterly flow once again, normal to above normal 500 mb
temperatures, and normal 700mb to 500mb lapse rates. This late short
term period forecast will start to be influenced by the now AL95,
located about 1500 miles east of the Windward Islands, and with a 80
to 90% chance of cyclonic formation in 2 to 7 days (according to the
NHC). The latest tropical weather outlook informs that a tropical
depression or storm is likely to form within the next day or so and
is expected to be near or north of the northern Leeward Islands on
Thursday and Friday. Residents and visitors should monitor updates
regarding this system.

.LONG TERM...Friday through Tuesday...

The forecast remains on track with the arrival of increased moisture
associated with a tropical wave (Invest 95L) into the region. The
National Hurricane Center (NHC) is currently monitoring an area of
low pressure over the central Atlantic with a high formation chance
of becoming a tropical cyclone within the next 48 hours (80%) and in
the next seven days (90%). This system is expected to gradually
become better organized over the next day and is likely to form into
a Tropical Depression or Tropical Storm soon. The latest model
guidance continues to suggest this system will be near or north of
the Lesser Antilles by Friday.

On Friday, moisture associated with the system, in combination with
daytime heating and local orographic effects, will enhance the
potential for convective activity (showers and thunderstorms) across
Puerto Rico and the U.S. Virgin Islands. By Sunday, as the system
moves north of the region, winds will veer from the south. This wind
shift, along with the arrival of trailing moisture from the system's
tail, will promote scattered showers and thunderstorms across
portions of central and northern Puerto Rico and the U.S. Virgin
Islands. Unstable conditions are expected to persist across the area
through at least Monday.

Conditions are expected to improve quickly by Tuesday as a high-
pressure system at all levels settles over the central Atlantic.
This pattern will promote drier and more stable atmospheric
conditions aloft through the end of the workweek.

Across the local area, uncertainty remains high in terms of precise
rainfall amounts and any potential local threats related to the
Invest 95L. Residents and visitors are therefore urged to monitor
the progress of this system closely over the coming days and stay
updated with the latest forecasts.

&&

.AVIATION...
(06Z TAFs)

Mainly VFR conditions expected to prevail. During the period, SHRA
and TSRA are forecast to continue reaching or moving close to
TJSJ/TIST/TISX, under ENE steering flow. Steering flow is expected
to gradually veer today and become more ESE. After around 17Z,
SHRA/TSRA over the Cordillera will spread mainly to
western/north/northwestern PR with TSRA affecting PR’s terminals or
their VCTY, mainly TJSJ/TJBQ. These can produce brief periods of
reduced visibilities and lower ceilings. Winds up to around 10 kts
with sea breeze variations and local effects, decreasing after 7/23Z.

&&

.MARINE...

A long-period northeasterly swell will gradually continue to fade
across the local Atlantic waters and passages today. A tropical wave
will influence the region through Wednesday, increasing the
frequency of showers and thunderstorms over the regional waters,
especially during the afternoon hours, with activity further enhanced
near coastal areas by diurnally driven convection.

&&

.BEACH FORECAST...

Although dissipating, a long-period northeasterly swell will
continue to produce life-threatening beach conditions through
later this afternoon, mainly along Atlantic-exposed beaches. A
moderate risk of rip currents is expected to return by Wednesday
through the upcoming weekend.

Please remember that rip currents can sweep even the best
swimmers away from shore into deeper water, where it becomes
difficult to return to safety. Residents and visitors are strongly
urged to monitor the latest beach forecast, follow the beach flag
warning system, and stay out of the water.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
538 AM AST Wed Oct 8 2025

.KEY MESSAGES...

* Another active day is expected across the islands with periods
of heavy rainfall and thunderstorm activity. There is a limited
to elevated flooding risk, particularly over the northwestern
quadrant of Puerto Rico.

* Frequent lightning, gusty wind conditions, and urban or small-
stream flooding are possible, with isolated flash flooding
cannot be ruled out.

* A Heat Advisory is in effect for the coastal and urban areas of
Puerto Rico from 10 AM to 4 PM AST. Vulnerable groups and
outdoor workers should stay aware of these conditions. Remember
to drink plenty of fluids, stay in an air-conditioned room and
out of the sun during the peak heat hours.

* For the US Virgin Islands, minor flooding and lightning possible
today due to showers and thunderstorms across the area.

* The National Hurricane Center (NHC) continues monitoring
Tropical Storm Jerry, located over the central Atlantic. This
system is expected to approach the northeast Caribbean by
Friday. Residents and visitors should remain informed and
monitor official updates from the National Hurricane Center and
our local office as Jerry approaches the Lesser Antilles.

&&

.SHORT TERM...Today through Friday...

Current satellite derived precipitable water (PWAT) values show
generally above 2 inches over the islands with isolated sectors at
around 1.8 in. A tropical wave over the region and a weakening upper
level low WNW of PR continue to contribute to this plume of moisture
over the region. Since midnight, most showers and t-storms remained
over the local waters, with some leaving low radar estimated
accumulations over eastern PR, Vieques, and Culebra. The highest
radar estimated accumulations as of 445 PM were observed over
central St. Croix, at 0.30 in. Lows were in the mid 70s to low 80s
over coastal and urban areas of Puerto Rico and in the mid 60s over
interior Puerto Rico. Lows were in the upper 70s to low 80s over the
USVI, Culebra and Vieques.

As the wave continues to move west-northwestward, southeasterly
steering flow will persist, bringing moisture into the islands. PWAT
will remain near or above 2.0 inches through the short-term period,
with current model guidance not being as aggressive with drier air
intrusion as before, for today, leaving PWAT values at around 1.88
inches over south and western Puerto Rico. In general high end
normal to above normal values will continue during the period as
moisture continues to be steered over the islands. The upper level
low will continue moving northward today, as an upper level ridge
starts to dominate. 500 mb temperatures are forecast to remain at
normal values at around -7 to -5 degrees Celsius, gradually
decreasing during the period. 925 mb temperatures will be normal to
above normal during the period, this and available moisture will
maintain above-normal temperatures and elevated heat indices, over
coastal and urban areas under periods of reduced cloud coverage. A
limited to elevated heat risk will be in effect today. A limited to
elevated flooding risk will persist with convective showers and
thunderstorms forecast for interior to western, northern and
northwestern Puerto Rico today, with lines of convection also
possible downwind of the local islands and El Yunque. Advective
shower and isolated t-storm activity is also forecast to affect
windward sectors of the islands during the morning and overnight
hours as the nearby above mentioned features provide enough
instability and moisture and as Tropical Storm Jerry continues to
approach the Caribbean. Hazards include lightning, gusty winds,
ponding of water and localized flooding associated with afternoon t-
storms. Minor to isolated flash flooding will be possible,
especially in areas with poor drainage or with more persistent rain.
On Thursday and Friday, the weather pattern will be influenced by
Tropical Storm Jerry, which is currently around 975 mi SE of St.
Croix, at coordinates 13.3N, 50.7W. The latest advisory has Jerry as
a hurricane with its closest approach being 196 miles NE of St. John
on Friday morning. However, uncertainty remains regarding its track
and intensity forecast. Under the latest guidance showers and
afternoon convection are still forecast to be under southeasterly
flow on Thursday and more southwesterly flow on Friday. Residents
and visitors should remain informed and monitor official updates
from the National Hurricane Center and our local office.

.LONG TERM...Saturday through Wednesday...

The forecast remains on track, with the arrival of trailing moisture
associated with Tropical Storm Jerry. Latest precipitable water
(PWAT) guidance indicates values above the normal climatological
range (2.25 to 2.50 inches) across the region. This suggests a wet
and moist pattern is likely from Saturday through at least Monday
across Puerto Rico and the U.S. Virgin Islands. As Tropical Storm
Jerry tracks north of the region, prevailing winds will initially be
southeasterly, then will shift from the southeast starting Sunday.

Showers and thunderstorms are expected this weekend, a result of the
high moisture environment combined with daytime heating and local
effects. While most of the area will experience some activity
associated with the system, the U.S. Virgin Islands are expected to
observe most of the activity due to their closer proximity to the
storm's path. Portions of eastern Puerto Rico, Culebra, and Vieques
will also observe frequent showers. On Saturday, with winds
prevailing from the south, activity will be focused over central and
northern Puerto Rico, including the San Juan metro area, mainly
during the afternoon hours. From Sunday onward, as winds shift from
the southeast, the activity will primarily focus over central Puerto
Rico toward the northwestern quadrant of the island.

Under this persistent moist pattern, the risk of flooding remains
elevated through the beginning of the workweek. Additional hazards
include: urban and small stream flooding, minor flooding in low-
lying areas, quick river rises, the potential for landslides, and
frequent lightning.

Conditions are expected to improve quickly starting Tuesday as a
surface high-pressure system and a mid-level ridge settle over the
central Atlantic. This pattern will promote drier and more stable
atmospheric conditions through the end of the forecast period.

Residents and visitors are urged to continue monitoring the progress
of Tropical Storm Jerry and updates from the National Hurricane
Center and our local office as the system approaches the Lesser
Antilles.

&&

.AVIATION...
(06Z TAFs)

Mainly VFR conditions to prevail. Due to a tropical wave, SHRA and
TSRA over the waters can reach or move close to TJSJ/TIST/TISX/TJPS,
under ESE steering flow, during the period. After around 17Z,
SHRA/TSRA over the Cordillera will spread mainly to
western/north/northwestern affecting PR’s terminals or their VCTY,
mainly TJSJ/TJBQ. These can produce brief periods of reduced
visibilities and lower ceilings. Winds up to around 12 kts with sea
breeze variations and higher gusts, decreasing after 8/23Z.

&&

.MARINE...

Moisture associated with a tropical wave will influence the region
today, increasing the frequency of showers and thunderstorms over
the regional waters, especially during the morning and afternoon
hours. Tropical Storm Jerry is expected to move northeast of the
region by Friday. Tropical storm conditions are possible by Thursday
night, mostly across the eastern half of the regional waters
including Atlantic and Caribbean waters, and the Anegada Passage.

&&

.BEACH FORECAST...

A moderate risk of rip currents will continue to persist across
the exposed Atlantic beaches of Puerto Rico, Culebra, and the U.S.
Virgin Islands through at least Friday. The risk is expected to
become high for Saint Croix by the end of the workweek as
Tropical Storm Jerry approaches the region. We encourage people to
stay updated for any changes in the forecast from the National
Hurricane Center.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Thu Oct 9 2025

.KEY MESSAGES...

* Convective afternoon showers and thunderstorms are forecast
mainly across interior, northern, and western Puerto Rico. Lines
of convection are also possible downwind of the local islands
and El Yunque.

* A Heat Advisory is in effect from 10 AM to 4 PM AST for coastal
and urban areas of Puerto Rico, Vieques, Culebra, and the U.S.
Virgin Islands.

* Tropical Storm Jerry is located around 470 miles SE of St.
Croix. The system is expected to approach the northeast
Caribbean by late tonight and tomorrow, with its closest
approach at about 198 miles ENE of St. Thomas.

* Hazardous marine and beach conditions are forecast as swells
from Jerry reach the regional waters by late tonight and
continue into Saturday. A Small Craft Advisory is in effect for
the offshore Atlantic Waters and Anegada Passage.

* Deep tropical moisture from Jerry will help support rounds of
showers and thunderstorms.

* For the U.S. Virgin Islands, particularly St. Thomas and St.
John, conditions could deteriorate further than in the rest of
the forecast area. Periods of gusty winds, rough seas, and
locally heavy rainfall are possible from Friday into the
weekend.

&&

.SHORT TERM...Today through Saturday...

Mostly fair weather conditions prevailed overnight across the
forecast area. Radar and satellite imagery showed isolated showers
over the waters and the vicinity of the U.S. Virgin Islands, along
with just a few clouds. Radar estimates indicated minimal rainfall
amounts. Surface weather stations across the islands recorded low
temperatures in the mid-70s to low 80s in coastal and urban areas,
and in the mid to upper 60s across interior Puerto Rico.

Today, Thursday, another active afternoon in terms of rain is
expected. Current satellite-derived precipitable water (PWAT) values
range from approximately 2.00 to 2.20 inches. A weakening upper-
level trough will continue to exert a slight influence on the region
while shifting to the northwest, followed by the arrival of an upper-
level ridge. A limited to elevated flooding risk will persist this
afternoon, with convective showers and thunderstorms forecast across
interior, northern, and western Puerto Rico. Lines of convection are
also possible downwind of the local islands and El Yunque.

Winds are expected to be light and from the east-southeast today,
turning more northerly tonight due to the influence of Tropical
Storm Jerry. Temperatures at the 925 mb level will be about one
standard deviation above normal. Combined with available moisture,
this will maintain above-normal surface temperatures and elevated
heat indices. A Heat Advisory is in effect from 10 AM to 4 PM AST
for coastal and urban areas of Puerto Rico, Vieques, Culebra, and
the U.S. Virgin Islands.

By Friday and Saturday, unstable weather conditions will prevail,
mainly due to the evolution and track of Tropical Storm Jerry. Heavy
rainfall is forecast for the U.S. Virgin Islands through Saturday,
which could result in flooding, particularly in areas with steep
terrain. According to the latest 2 AM bulletin from the National
Hurricane Center (NHC), Jerry is forecast to pass northeast of the
local islands tomorrow as a Category 1 hurricane. We will experience
indirect impacts from this system, such as outer rainbands and
associated instability, which could enhance shower and thunderstorm
activity, especially on Friday afternoon and Saturday. For that
reason, an elevated flooding risk is expected across portions of
Puerto Rico and the U.S. Virgin Islands on both days.

Residents and visitors are encouraged to stay informed and monitor
official updates from the National Hurricane Center and the local
National Weather Service office in San Juan.

.LONG TERM...Sunday through Thursday...


The latest Advisory by the National Hurricane Center has Tropical
Storm Jerry, a hurricane by that time, about 740 miles north of
San Juan by Sunday. Moisture plume trailing Jerry will continue to
promote PWAT values generally at 2 to 2.3 inches, normal to above
normal values for this time of the year, through at least late
Monday, with deep moisture being present. On Monday above normal
moisture will gradually filter out to the west while drier air
filters in from the east. Steering flow will start southeasterly
on Sunday, gradually becoming more easterly on Monday. Patches of
below normal to above normal moisture will filter over the islands
Tuesday through Wednesday. Mid to upper level ridging will be
present for most of the period, however a deep level trough will
dig down towards the eastern Caribbean by Wednesday and Thursday.
Current model guidance has an increase in PWAT values once again
late Wednesday into Thursday as moisture from a frontal boundary
moves over the area bringing above 2 inches of PWAT to end the
forecast period. As a surface low moves towards the western
Atlantic and a high positions itself over the eastern Atlantic,
steering flow will become southeasterly on Tuesday, southerly to
southwesterly on Wednesday and southwesterly by Thursday. Flooding
risk remains, particularly during afternoon convection steered by
the dominant winds, due to diurnal heating, sea breeze
convergence and local effects, and due to the plumes of moisture
at the beginning and end of the forecast period. Southerly
component of the winds will also aid in sustaining a heat risk
during the period.


&&

.AVIATION...
(06Z TAFs)

VFR conditions should prevail this morning across most TAF sites.
VCSH are likely at USVI sites. After 17Z–18Z, SHRA/TSRA developing
over the Cordillera will reach TAF sites, potentially causing
intermittent periods of MVFR conditions with reduced VIS through
09/22Z. E to SE winds at 8 to 10 knots are expected, with sea breeze
variations. Winds will decrease after 09/22Z, becoming light and
variable and rain chances increasing for the USVI sites overnight.


&&

.MARINE...

Tropical Storm Jerry is currently over the central Atlantic and
forecast to pass well northeast of the local islands by late tonight
into Friday. Although no direct tropical storm impacts are expected,
indirect marine impacts will spread across the regional waters by
late tonight night into the weekend. Swells generated by Jerry will
lead to hazardous seas up to 8 to 9 feet, particularly across the
offshore Atlantic waters and the Anegada Passage, where a Small
Craft Advisory will be in effect from late tonight through late
Friday night. Mariners should exercise caution, as conditions are
expected to deteriorate late tonight through early in the weekend
before gradually.

&&

.BEACH FORECAST...

A moderate risk of rip currents will be in effect today and tonight
for the northern and eastern beaches of Puerto Rico as well as
beaches of Culebra, Vieques and the USVI. From Friday and into the
weekend, a high risk of rip currents will prevail for those areas as
swells from Tropical Storm Jerry begin to affect the local waters.
These swells will gradually increase in height by Thursday night,
leading to hazardous surf conditions with breaking waves up to 6 to
7 feet along exposed beaches. Conditions are expected to gradually
improve to moderate conditions early next week.

Heed the advice of lifeguards, beach patrol flags and signs. If you
become caught in a rip current, yell for help. Remain calm, do not
exhaust yourself and stay afloat while waiting for help. If you have
to swim out of a rip current, swim parallel to shore and back toward
the beach when possible. Do not attempt to swim directly against a
rip current as you will tire quickly.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
537 AM AST Fri Oct 10 2025

.KEY MESSAGES...

* Tropical Storm Jerry will pass well to our northeast this
morning before continuing its track towards the open Atlantic.
Its closest approach to St. John was at around 5 AM at
approximately 152 miles, and its closest approach to San Juan
will be at around 8 AM at about 231 miles.

* Deep tropical moisture from Jerry will help support rounds of
showers and thunderstorms through the weekend, maintaining a
moderate risk of flooding, mostly for eastern Puerto Rico and
the U.S. Virgin Islands.

* Hazardous marine conditions for small crafts and hazardous beach
conditions are forecast as swells from Jerry continue affecting
the regional waters through Saturday.

* For the U.S. Virgin Islands, particularly St. Thomas and St.
John, conditions could deteriorate further as periods of gusty
winds and locally heavy rainfall are possible today into the
weekend.


&&

.SHORT TERM...Today through Sunday...

During the overnight period, some showers and a few thunderstorms
moved across the local waters, with some reaching the northeast
corner of Puerto Rico. Radar estimates indicated rainfall
accumulations of one inch or less across eastern municipalities.
Surface weather stations across the islands recorded low
temperatures in the mid 70s to low 80s in coastal and urban areas,
and in the mid to upper 60s across interior Puerto Rico. Winds have
been mainly light and variable.

Today, Tropical Storm Jerry will pass to the northeast of Puerto
Rico and the U.S. Virgin Islands. Its closest approach to St.
John was at around 5 AM at approximately 152 miles, and its
closest approach to San Juan will be at around 8 AM at about 231
miles. It is expected to move away from the islands later today.
According to the latest 5 AM bulletin from the National Hurricane
Center (NHC), the center of Tropical Storm Jerry was located near
latitude 19.2 North, longitude 62.5 West. Jerry is moving toward
the northwest near 17 mph.

This storm will bring indirect impacts to our forecast area through
at least Saturday. Weak northerly steering winds will dominate
during the morning hours, then gradually shift to acquire a
southerly component due to Jerry’s influence. The latest satellite
derived precipitable water (PWAT) values range in the from normal to
above normal, approximately 2.00 to 2.20 inches across the region.
The combination of these variables and local effects will promote
slow-moving convection capable of producing heavy rainfall, frequent
lightning, and localized gusty winds. Therefore, an elevated flood
risk is expected, particularly across interior and eastern Puerto
Rico and the U.S. Virgin Islands today and Saturday. The rainfall
forecast have 2 to 4 inches of rain expected for the USVI. For
eastern Puerto Rico, moisture associated with Jerry combined with
local orographic effects may result in up to 2 to 4 inches of rain,
with isolated 6 inches possible. This rainfall could result in flash
flooding, particularly in urban areas and in steep terrain. In terms
of heat for today, there is a limited heat risk across urban and
coastal areas of Puerto Rico and the USVI, however some areas may
experience locally higher heat indices, especially in areas with
less rain or cloud coverage. We will continue to monitor the heat
threat during the morning in case any advisory is needed.

By Sunday, lingering tropical moisture combined with southeasterly
winds will continue to bring warm, humid, and unstable weather
conditions. Afternoon thunderstorms are likely to redevelop across
interior and northwestern Puerto Rico due to sea breeze
interactions. Residents and visitors are encouraged to stay informed
and follow official updates from the National Hurricane Center and
the National Weather Service office in San Juan.


.LONG TERM...Monday through Friday...

Drier air will filter in to start the workweek under easterly flow,
displacing the moisture plume related to Jerry. Patches of below
normal to above normal moisture will filter over the islands Tuesday
through Wednesday and then gradually increasing during the second
half of the workweek. Mid to upper level ridging will be present to
start the period, however model guidance has an upper level low
approaching the Caribbean by midweek. Latest runs have backed off on
the deep level trough digging down towards the Caribbean during the
second half of the period. However, as its surface low moves towards
the northwestern Atlantic and a high positions itself over the
eastern tropical Atlantic, steering flow will become southeasterly
on Tuesday, southeasterly to southerly on Wednesday and southerly
through most of the rest of the period. PWAT values are forecast to
gradually increase Thursday and Friday as both moisture from a
frontal boundary approaches from the north and southerly flow steers
tropical moisture over the region, these features can bring above 2
inches of PWAT to end the forecast period. Flooding risk remains,
particularly during afternoon convection steered by the above
mentioned dominant winds, due to diurnal heating, sea breeze
convergence and local effects, and due to the plumes of moisture at
the beginning and end of the forecast period. Surface winds will be
generally light to moderate through Tuesday, becoming light
Wednesday onwards as the southerly component establishes itself.
This southerly component will also aid in sustaining a heat risk
during the period. Low concentrations of Saharan Dust will also be
present to start the workweek.

&&

.AVIATION...
(06Z TAFs)

VFR conditions should prevail this morning across most TAF sites.
Tropical Storm Jerry will pass to the northeast of Puerto Rico and
the U.S. Virgin Islands today, cloudiness increasing. VCSH are
likely across TJSJ and USVI TAF sites during the morning period,
After 16Z–18Z, SHRA/TSRA developing over the Cordillera will reach
TAF sites, potentially causing intermittent periods of MVFR
conditions, locally gusty winds and reduced VIS. The general flow
will remain variable today with sea breeze variations. Tonight, USVI
sites have a moderate to high chance to observe periods of heavy
rain and t-storms.

&&

.MARINE...

Tropical Storm Jerry is now about 155 miles northeast of St. John
and about 235 miles northeast of San Juan. This system will
continue moving northwestward at a safe distance from Puerto Rico
and the USVI. Although no direct tropical storm impacts are
expected, indirect marine impacts will continue spreading across
the regional waters through late tonight and early Saturday.
Swells generated by Jerry will lead to hazardous seas up to 8 to 9
feet, particularly across the offshore Atlantic waters and the
Anegada Passage, where a Small Craft Advisory is in effect through
late tonight. Conditions are forecast to gradually improve late
Saturday onwards.


&&

.BEACH FORECAST...

A high risk of rip currents will be in effect this morning for
the beaches of the USVI as swells from Tropical Storm Jerry begin
to affect the local waters. The high risk of rip currents will
then spread to Vieques, Culebra and Puerto Rico (north and east
facing beaches), this evening. These swells can lead to hazardous
surf conditions with breaking waves up to 6 to 7 feet along
exposed beaches. Conditions are expected to gradually improve to a
moderate risk of rip currents by tomorrow evening.

Heed the advice of lifeguards, beach patrol flags and signs. If you
become caught in a rip current, yell for help. Remain calm, do not
exhaust yourself and stay afloat while waiting for help. If you have
to swim out of a rip current, swim parallel to shore and back toward
the beach when possible. Do not attempt to swim directly against a
rip current as you will tire quickly.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
507 AM AST Sat Oct 11 2025

.KEY MESSAGES...

* Tropical Storm Jerry will continue to move further away from the
northeastern Caribbean today. Deep tropical moisture from Jerry
will help support rounds of showers and thunderstorms through
the weekend, maintaining an elevated risk of flooding, mostly
for interior and eastern Puerto Rico and the U.S. Virgin
Islands.

* For the U.S. Virgin Islands, elevated flood risk remains in
place today as additional periods of gusty winds and locally
heavy rainfall are possible.

* Small Craft Advisory remains in effect through noon today across
the offshore Atlantic waters and the Anegada Passage due to a
fading swell resulting in seas up to 7 feet.

* Warm to hot conditions are expected each day, particularly
tomorrow into the beginning of the workweek.

&&

.SHORT TERM...Today through Monday...

Tropical Storm Jerry will continue to move further away from the
northeastern Caribbean today; however, higher than normal
precipitable water (PWAT) content near 2.20 inches is expected to
linger over the region through at least early Sunday, while the 850-
700mb lapse rates indicate a more unstable profile today. Therefore,
mid-to upper-level cloudiness, showers, and thunderstorm development
associated with the outer bands of TC Jerry will continue across
most local waters. Under southerly steering winds, some of this
activity will move at times across the USVI and over the southern
and eastern sections of PR, where the flood threat remains elevated.

On Sunday and Monday, winds will acquire an easterly component and
become light to moderate, which will favor afternoon convection over
western PR, triggered by the sea breeze convergence in combination
with daytime heating and the available low-level moisture content.
The PWAT content is expected to drop to near normal levels (1.75
inches) by Monday across the entire CWA. Therefore, a transition
into a generally fair weather pattern across the USVI is expected
late Sunday and Monday, while in PR, afternoon thunderstorms are
expected each day over portions of the western interior.

Warm to hot conditions are expected each day, particularly on Sunday
and Monday, where Heat Advisory conditions are expected, mainly over
the north-central to western coastal municipalities of PR. High
temperatures are expected to range from the upper 80s to low 90s
across most lower elevations each day; however, the cloud coverage
today could limit the heat threat across the islands in general.


.LONG TERM...Tuesday through Saturday...

The long-term forecast remains generally on track. Surface winds
will remain light around Tuesday and Wednesday with an easterly
component, then shift southerly and increase to moderate for the
rest of the forecast period. The southerly component will likely
sustain an elevated heat risk during this time. Drier air will
filter in at the start of the workweek under easterly flow,
displacing the moisture plume related to Jerry. Patches of below-
normal to above-normal moisture will move over the islands Tuesday
through Wednesday.

Mid to upper level ridging will be present at the beginning of
the period, however, model guidance shows an upper-level low
approaching the Caribbean by midweek. The 500 mb temperatures will
become cooler, enhancing thunderstorm development each afternoon.
Model guidance indicates that PWAT values are forecast to
increase, particularly from Thursday through Saturday, as both
moisture from a frontal boundary approaches from the north and
southerly flow steers tropical moisture over the region. These
features may bring PWAT values above 2 inches by the end of the
forecast period which is considered above normal values.

At this time, flood risk remains limited on Tuesday and Wednesday,
but will likely increase to elevated levels from Thursday onward,
particularly during afternoon convection influenced by the
dominant winds, diurnal heating, sea breeze convergence, and local
effects. This means flooding in urban areas, roads, small streams,
and washes will remain in the forecast.

&&

.AVIATION...
(06Z TAFs)

Outer rainbands from TC Jerry will continue to produce SHRA/TSRA
across the local area today. This can lead to tempo MVFR to brief
IFR conds, mainly at TJPS/TIST/TISX. Elsewhere, mostly -RA/VCTS
expected. SCT/BKN lyrs btw FL030-FL120 and mtn tops obscd
expected. SSW winds gradually bcmg SSE up to 15 kt are expected
today with sea breeze variations along the northern coast of PR.

&&

.MARINE...

Gentle to moderate southerly winds as Jerry moves away to the north.
Indirect impacts from Jerry will continue through today, with a
fading swell resulting in seas up to 7 feet across the offshore
Atlantic waters and the Anegada Passage. Thus, a Small Craft
Advisory remains in effect through noon today. Additionally,
periods of showers and thunderstorms from its outer bands will
continue today across portions of the waters. Conditions are
forecast to gradually improve this afternoon onward.

&&

.BEACH FORECAST...

A moderate risk of rip currents is in place today across beaches
along the northern, eastern, and southeastern coast of Puerto
Rico, Vieques, Culebra and the USVI. That means life-threatening
rip currents are possible in the surf zone and beachgoers need to
exercise caution. Over the coming days, similar conditions will
dominate. For more information, please refer to the Surf Zone
Forecast for Puerto Rico and the U.S. Virgin Islands (SRFSJU) or
visit weather.gov/beach.

Heed the advice of lifeguards, beach patrol flags and signs. If you
become caught in a rip current, yell for help. Remain calm, do not
exhaust yourself and stay afloat while waiting for help. If you have
to swim out of a rip current, swim parallel to shore and back toward
the beach when possible. Do not attempt to swim directly against a
rip current as you will tire quickly.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Sun Oct 12 2025

.KEY MESSAGES...

* Abundant low-level moisture combined with locally effects will
result in showers across eastern Puerto Rico this morning and
thunderstorms across western sectors this afternoon. Limited to
elevated flood risk is in place.

* A Heat Advisory is in effect from 10 AM to 5 PM AST for coastal
and urban areas of Puerto Rico, Vieques, Culebra, and the U.S.
Virgin Islands.

* The U.S. Virgin Islands will experience showery weather,
particularly during early mornings and nights.

* By Thursday into around Saturday, dynamics will be more
favorable for widespread showers and stronger thunderstorms.

&&

.SHORT TERM...Today through Tuesday...

Persistent showers and thunderstorms developed mainly over the
Caribbean waters and local passages, with some activity moving
across the U.S. Virgin Islands and eastern Puerto Rico, including
Vieques and Culebra. Rainfall estimates were around a quarter of
an inch in these areas. Overnight lows ranged from the upper 60s
in higher elevations to around 80 to 82°F along coastal locations,
remaining slightly warmer than normal. Winds were generally light
to calm and variable over land, resulting in limited cooling and
a warm, humid night.

Extreme heat will be the main hazard today, as clearer skies and
east-southeasterly winds boost sunshine and pull in warm, humid
air. A Heat Advisory is in effect for coastal and urban areas of
Puerto Rico and the U.S. Virgin Islands, including Vieques and
Culebra, where feels-like temperatures will likely climb well
above normal, reaching levels that impact most heat-sensitive
individuals, especially those without cooling or proper hydration.
Aloft, a persistent ridge will maintain a trade wind cap and
support drier air aloft, limiting widespread storms. However, with
abundant low-level moisture (PWAT values above 2 inches), intense
heating, and sea-breeze convergence, localized afternoon showers
and thunderstorms are still likely, especially downwind of the
mountains and across the northwest quadrant. Any storm could
produce brief heavy rain, localized flooding, lightning, or gusty
winds. Except for some lingering showers, most hazard risks will
diminish after sunset (after 6:03 PM AST) as daytime heating fades
and instability weakens. Winds will become more easterly later
today as a surface high builds north, but conditions will remain
hot, muggy, and spotty-stormy until early evening.

A strengthening mid- to upper-level ridge will reflect downward
as a surface high, becoming the dominant low-level feature and
maintaining a gentle to moderate easterly breeze tonight, backing
ENE Monday night, then veering ESE and weakening to light winds by
Tuesday night. This high-pressure pattern will lock in
subsidence, a strong inversion, and anomalously warm mid-level
temperatures well above normal, creating an increasingly hostile
environment for widespread convection. Moisture will fluctuate in
patches, with a brief drier period Monday morning, then near-
normal values thereafter, and while heat risks will persist, they
should ease slightly after today as winds turn more E-NE. Rainfall
will remain highly localized and mainly driven by afternoon
heating, with any showers brief, steered by the prevailing flow,
and limited in coverage, though isolated thunder or minor flooding
cannot be ruled out. By late Tuesday night, winds will diminish
in response to an approaching frontal boundary from the northwest,
signaling a potential pattern change heading into the workweek.


.LONG TERM...Wednesday through Sunday...

At the beginning of the long-term period, we will be transitioning
into more favorable conditions for increased shower coverage and
stronger thunderstorms. The mid- to upper-level ridge will begin
to be replaced by a deep-layer trough, while 500 mb temperatures
cool, enhancing thunderstorm development during the afternoon
hours. On Wednesday, surface winds will be light with an easterly
to southeasterly component, then from Thursday onward, winds will
shift to a more southerly direction and remain light. On Wednesday,
afternoon convection is expected to develop over the interior and
move into the western sectors of Puerto Rico. Latest model
guidance indicates that precipitable water (PWAT) values will
remain near average through the period, ranging from 1.9 to 2.0
inches. From Thursday through Saturday, a frontal boundary will
approach and stall north of the area, while southerly flow steers
tropical moisture over the region. Relative humidity values in the
mid to upper levels will increase to above-normal levels.
Additionally, the southerly flow is expected to sustain an
elevated heat risk, with 925 mb temperatures showing values above
two standard deviations. Overall, expect typical afternoon
convection on Wednesday. However, from Thursday through Saturday,
the combination of the mentioned variables, better atmospheric
dynamics and moisture will support stronger afternoon
thunderstorms, increasing the potential for flooding across the
region. This includes flooding of urban areas, roads, small
streams, and washes. By Sunday, ridging is expected to begin
dominating the region once again.

&&

.AVIATION...
(06Z TAFs)

Variable weather conditions will prevail today. SHRA/TSRA are
expected across USVI terminals (TIST/TISX), TJSJ, and TJPS through
12/14Z, with MVFR to brief IFR CIGS/VIS possible in heavier
activity. Additional SHRA/TSRA are likely this afternoon over
interior and NW PR, affecting TJSJ and TJBQ mainly between
12/16-21Z, again producing brief MVFR/IFR restrictions. Most
convection will diminish after sunset. Winds LGT/VRB overnight,
increasing to 10–14 kt from the ESE-E after 12/13Z with sea-breeze
influences, then becoming LGT/VRB again after 12/22Z.

&&

.MARINE...

Gentle to moderate east to southeast winds will prevail over the next
few days as the remnants of Jerry shift well north of the area and a
surface high pressure builds across the Central Atlantic. Above normal
moisture content will continue to result in showers and thunderstorms
across the waters this morning, and across the norwestern waters of
Puerto Rico this afternoon. Seas generally below 5 feet throughout
the forecast period.

&&

.BEACH FORECAST...

A low risk of rip currents is present today, however a moderate
risk should return by tonight across beaches along the northern
and eastern coasts of Puerto Rico, Culebra and St. Thomas. That
means life-threatening rip currents are possible in the surf zone
and beachgoers need to exercise caution. Over the coming days,
similar conditions will dominate. For more information, please
refer to the Surf Zone Forecast for Puerto Rico and the U.S.
Virgin Islands (SRFSJU) or visit weather.gov/beach.

Heed the advice of lifeguards, beach patrol flags and signs. If
you become caught in a rip current, yell for help. Remain calm, do
not exhaust yourself and stay afloat while waiting for help. If
you have to swim out of a rip current, swim parallel to shore and
back toward the beach when possible. Do not attempt to swim
directly against a rip current as you will tire quickly.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
506 AM AST Mon Oct 13 2025

.KEY MESSAGES...

* More stable to typical weather conditions are expected over the
next few days. However, from Thursday through Saturday,
conditions will become more favorable for widespread showers and
stronger thunderstorms, increasing the risk of urban and small-
stream flooding, rapid river rises, frequent lightning, and
gusty winds.

* There is a limited heat risk today; however, southerly wind
flow will bring above-normal temperatures combined with elevated
moisture, which could result in an elevated to significant heat
threat, particularly from Tuesday onward.

* A northerly swell could lead to deteriorating marine and
coastal conditions by the end of the week into next week.

* In the U.S. Virgin Islands, the main threats this week are heat,
along with the return of life-threatening rip currents and
hazardous seas by the end of the week into next week.

&&

.SHORT TERM...Today through Wednesday...

Isolated to scattered showers developed over the surrounding waters
and, steered by moderate easterly winds, some moved into eastern
Puerto Rico, including Vieques and Culebra, as well as the U.S.
Virgin Islands. The highest rainfall totals so far are around half
an inch in southeastern Puerto Rico. Temperatures showed a strong
land–sea contrast, with lows dropping into the low 60s in higher
elevations, while exposed coastal areas remained warm in the 80–82°F
range. Conditions were slightly warmer and drier than the previous
night, reflecting a patchy wet/dry pattern. Across land areas, winds
were generally light to calm and variable.

A mostly quiet morning will turn more active this afternoon as
daytime heating and sea breezes trigger scattered to locally
numerous showers and isolated to scattered thunderstorms, mainly
across the western interior and west. A strong ridge aloft will
continue to limit widespread storm development by keeping the
atmosphere capped and somewhat dry above the surface, but low-level
moisture will increase by mid-afternoon, allowing for brief heavy
rain and localized flooding. Winds will remain moderate to locally
fresh out of the east due to surface high pressure to the north, and
while temperatures will be slightly cooler than recent days, heat
may still affect vulnerable individuals in urban and coastal areas
of north-central Puerto Rico. Tonight, winds will weaken and a surge
in moisture (higher PWAT) will allow slow-moving showers to drift
inland from the waters into eastern Puerto Rico and the U.S. Virgin
Islands, bringing a continued chance of additional rainfall before
hazards gradually decrease with cooling temperatures and fading
instability.

A gradual but important pattern shift is expected over the next
48–72 hours as the mid- to upper-level ridge finally shifts
eastward, allowing a deep-layer trough over the western Atlantic to
support a coastal low and push the season’s first frontal boundary
and its pre-frontal trough southeastward toward the region. Model
guidance clearly shows this transition through veering and weakening
winds, increasing PWAT values, and cooling mid-level temperatures,
all of which point to a wetter and more unstable environment
developing by Wednesday. As winds shift from east to southeast and
then south to southwest, hotter air and rising moisture will
increase heat stress. By Wednesday night, a surge of tropical
moisture will push PWAT values above 2 inches, while mid-level
temperatures cool back to normal, reducing inhibition and enhancing
instability. With light winds, high moisture, and increasing
instability in place, slow-moving showers and thunderstorms will
become more likely, raising the risk of localized flooding and
lightning impacts, especially Wednesday afternoon and night.


.LONG TERM...Thursday through Monday...

The long-term period remains generally unchanged, but a transition
into more favorable conditions for increased shower coverage and
stronger thunderstorms is expected from Thursday onward. According
to the latest guidance, the influence of a deep-layer trough and
its associated frontal boundary will linger to the north of the region,
while southerly flow continues to transport tropical moisture
over the area. Model guidance also indicates that precipitable
water (PWAT) values will stay near average, ranging between 1.9
and 2.0 inches. In addition, mid- to upper-level relative humidity
is forecast to increase to above-normal levels. Cooling
temperatures at 500 mb, from around -4°C to -6 or -7°C, will
enhance stronger thunderstorm development during the afternoon
hours. Winds will shift to a more southerly direction and remain
light. Also, the southerly flow will also contribute to elevated
heat risk, with 925 mb temperatures exceeding two standard
deviations above normal, likely prompting the issuance of Heat
Advisories for urban and coastal areas.

Overall, the combination of these factors will support increased
shower activity and stronger thunderstorms each afternoon, at
least through the end of the week. The flood risk will remain
elevated on a daily basis, especially in areas with saturated
soils or poor drainage. Potential impacts include ponding of water
on roads and in poorly drained areas, urban flooding (especially
in low-lying zones), and rising water levels in small streams,
rivers, and washes.

By Sunday onward, conditions are expected to become more typical,
still with some afternoon convection due to local effects, as
surface high pressure building over the central Atlantic helps
lift the frontal boundary. A mid-level ridge becomes dominant
aloft, ushering drier air into the mid-levels. However, the
tropics should continue to be monitored, as some forecast models
are indicating the possible approach of a tropical wave after
Monday.

&&

.AVIATION...
(06Z TAFs)

Variable weather expected. Patchy SHRA early, then coverage
increases this afternoon. SHRA/TSRA likely across all PR terminals
13/16-22Z, with brief MVFR/IFR VIS/CIG in heavier cells. USVI
terminals will also see periods of SHRA, steered by E winds 8–14 kt.
Most activity will fade after sunset but may linger at TJSJ, TJBQ,
and USVI terminals overnight. Winds LGT/VRB (0–6 kt)
overnight/morning, increasing to 10–14 kt from ESE–E with sea
breeze, then LGT/VRB again after 13/22Z.

&&

.MARINE...

Gentle to moderate east to southeast winds will prevail through
Tuesday as a surface high-pressure system dominates across the
central Atlantic. From Wednesday onward, light to gentle southerly
winds are expected. Today, isolated to scattered showers embedded
in the trade winds are anticipated, with showers and thunderstorms
possibly developing across the northwestern waters of Puerto Rico
this afternoon. Shower activity is expected to increase around
Thursday due to an approaching frontal boundary. Looking ahead, a
northerly swell could lead to deteriorating marine conditions by
next weekend and into early next week.

&&

.BEACH FORECAST...

A moderate risk of rip currents is present today across beaches
along the northern and eastern coasts of Puerto Rico, Culebra and
St. Thomas. That means life-threatening rip currents are possible
in the surf zone and beachgoers need to exercise caution. Tomorrow,
Tuesday, similar conditions are expected to prevail, followed by
improving conditions with low risk for Wednesday and Thursday. At
the end of the week into the weekend, the risk will gradually
increase again. For more information, please refer to the Surf
Zone Forecast for Puerto Rico and the U.S. Virgin Islands (SRFSJU)
or visit weather.gov/beach.

Additional beach hazards over the coming days will include:
elevated heat risk and afternoon thunderstorms. Beachgoers are
advice to remain hydrated and seek shelter immediately if you hear
thunder.

&&