Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
517 AM AST Tue Oct 14 2025

.KEY MESSAGES...

* Warmer conditions will lead to hazardous heat conditions today.
A Heat Advisory is in effect for all urban and coastal areas of
Puerto Rico and the U.S. Virgin Islands from 10 AM through 5 PM
AST today.

* A deep-layer trough and a frontal boundary will promote wet and
unstable conditions for the second part of the workweek across
the islands, increasing flooding and lightning threat.

* An increase in trade wind showers across the U.S. Virgin
Islands is expected during the nighttime.

* A northerly swell could lead to hazardous marine and coastal
conditions across the islands by the upcoming weekend into early
next week.

&&

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

Isolated to scattered trade-wind showers developed over the
surrounding waters overnight and moved inland or brushed coastal
areas, especially across eastern Puerto Rico, Vieques, Culebra, and
the U.S. Virgin Islands. The highest estimated rainfall totals
peaked around half an inch along coastal areas of the San Juan
metro, with lesser amounts elsewhere. Overnight temperatures showed
little overall change, with most interior and higher elevation
stations falling into the 70s or lower, while a few exposed coastal
sites in eastern Puerto Rico, the USVI, and local islands remained
in the low 80s. Winds were generally light to calm and variable, but
brief gusts occurred near passing showers.

A broad surface high to the north and ridging aloft will keep drier
air and warm mid-level temperatures in place, maintaining a weak
trade wind cap that limits storm growth early and allows more
sunshine and heat to build. Low-level temperatures will remain well
above normal and southeasterly flow will increase moisture,
resulting in extreme heat concerns, and a Heat Advisory is in effect
for all islands, especially urban and coastal areas. Morning trade
wind showers will affect windward and eastern zones, followed by
scattered to locally numerous afternoon showers and isolated
thunderstorms across the western interior and northwest, where brief
heavy rain, localized flooding, and dangerous lightning are possible.

A significant shift toward a wetter and more unstable pattern will
develop as the ridge breaks down and a deep-layer trough with an
approaching frontal and pre-frontal trough influences the region—an
ideal setup for stronger convection and possibly severe
thunderstorms. Winds will veer from southeasterly tonight to
southerly and southwesterly on Wednesday, then become light and
variable by Thursday, allowing heat and moisture to build. Moisture
will increase well above what is typical for this time of year,
while mid-level temperatures cool to normal or slightly below-normal
levels—both of which strongly favor deep convective development. At
the same time, low-level winds will weaken, limiting storm steering
and allowing slow-moving thunderstorms to persist. Extreme heat will
continue as well-above-normal low-level temperatures and southerly
flow trap hot, humid air. As a result, showers and thunderstorms
will become more widespread and longer-lasting from Wednesday
afternoon through Thursday night, bringing a growing threat of
frequent lightning, gusty winds, and localized flooding. Hazards
will increase each day, peaking late Wednesday into Thursday and
Thursday night.

&&

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

No major changes were introduced to the long-term forecast. A wet
and unstable weather pattern is expected for the upcoming weekend,
which may improve for the first part of the workweek. Winds should
remain light on Friday and Saturday, shifting from the southwest
influenced by a surface high pressure system over the central
Atlantic and a broad polar trough, which will pool the remnants
of the frontal boundary and high tropical moisture. From the
latest deterministic guidance of the GFS and the ECMWF,
Precipitable Water (PWAT) values should remain seasonal to above
climatological normal (2.0 - 2.2 inches). Additionally, the polar
trough reflected in the mid to high levels may deepen enough to
cool 500 mb temperatures (-6.5 to -7.5 degrees Celsius),
increasing instability and supporting deep convection. The Galvez-
Davison Index (GDI) also suggests the potential of isolated to
scattered thunderstorms through at least Sunday. Hence, the
frequency of showers and thunderstorms should remain high,
affecting mostly windward sections during the night through early
mornings, with deep convection activity remaining over the
mountain ranges of Puerto Rico in the afternoons. Winds should
increase and turn from the southwest as the surface high pressure
migrates west and approaches the CWA. Due to abundant moisture
content over the area, afternoon convection should concentrate
over northwestern Puerto Rico. Given the expected conditions, the
lightning and flooding threat will remain limited to elevated
during that period.

An improvement in weather conditions is expected by late Monday due
a drier air mass filtering into the region. The latest model
guidance shows a decrease in PWAT values (1.7 - 1.9 inches),
although there’s high variability between ensemble members due to a
tropical wave that global models suggest should move south of the
CWA. Nevertheless, the combination of daytime heating, local
effects, and available moisture will enhance shower and thunderstorm
activity, mainly over the western/northwestern portions of Puerto
Rico; however, the flooding threat should remain limited.

The latest model guidance indicates that Sunday may be the
warmest day of the long-term period, followed by a gradual
decrease in 925 mb temperatures for the remainder of the period.
Nevertheless, heat indexes are still very likely to reach 100
degrees and may meet Heat Advisory Criteria. Hence, the heat
threat will remain elevated for the long-term forecast.


&&

.AVIATION...

(06Z TAFs)

Variable weather expected. Trades SHRA early, then SHRA/TSRA shifts
to w-nw this afternoon. SHRA/TSRA likely across all PR terminals
14/16-22Z, with brief MVFR/IFR VIS/CIG in heavier cells closer to
TJSJ and TJBQ. USVI terminals will also see periods of SHRA
throughout the day. 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 14/22Z.

&&

.MARINE...

A broad surface ridge north of the region continues to dominate the
local marine area, maintaining moderate east to east-southeast trade
winds today. Then, winds will become light to gentle from the south-
southwest Wednesday onwards. A frontal boundary approaching the
region will induce pre- frontal troughs for the second half of the
workweek, increasing shower and thunderstorm activity across the
regional waters and passages. Pulses of a northerly swell could
deteriorate marine conditions by next weekend into early next
week.

&&

.BEACH FORECAST...

For today and the rest of the workweek, the risk of rip currents
should remain moderate mainly over northern and eastern beaches of
Puerto Rico, Vieques , Culebra, and the U.S. Virgin Islands.
Although the risk is not high, life-threatening rip currents are
still possible along the surf zone. Additionally,showers and
thunderstorms in the afternoon may reach the western/northwestern
coastal areas, increasing the lightning threat. Beachgoers should
exercise caution and stay weather alert. Model guidance continues to
suggest the arrival of a northerly swell by the upcoming weekend,
expected to bring hazardous beach conditions along north- facing
beaches of Puerto Rico, Culebra, and the U.S. Virgin Islands.

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Wed Oct 15 2025

.KEY MESSAGES...

* There is a limited to elevated flooding risk across the
northern and eastern half of Puerto Rico. Flooding in urban
areas, roads, small streams, and washes possible, plan for water
ponding on roads and in poorly drained areas.

* An elevated/moderate heat threat is expected once again across
the urban and coastal municipalities or Puerto Rico and the US
Virgin Islands.

* Across the US Virgin Islands, there is a low chance of localized
urban and small streams flooding, regardless people should plan
accordingly.

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


&&

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

Isolated to scattered trade wind showers moved inland from the
surrounding waters overnight, mainly affecting eastern Puerto Rico,
Vieques, Culebra, and the U.S. Virgin Islands. However, the highest
rainfall since 8 PM occurred over western Puerto Rico, where
lingering afternoon and evening showers and thunderstorms produced
around three quarters of an inch of rain from Las Marias to
Mayaguez. Overnight lows remained similar to previous nights,
ranging from the upper 60s in higher elevations to the lower 80s in
the warmest coastal spots, although only one or two coastal
stations, mainly in Saint Thomas, reported temperatures in the 80s.
The steering flow began to veer overnight, but winds remained
generally light to calm and variable over land areas, with only
brief gusts near passing showers.

A deep layer trough and an approaching pre frontal trough will begin
increasing instability and moisture today. PWAT will rise through
the day and exceed typical values, while mid level 500 mb
temperatures begin to cool, gradually improving support for deeper
convection. Low level winds will veer from the south to southwest,
steering showers and isolated thunderstorms toward the north and
northeast during the afternoon, increasing flood risk in the north
central to northeastern sections, including the San Juan metro area.
Despite higher rain chances and the proximity of the frontal and pre
frontal trough, elevated heat risk will continue due to very warm
low level temperatures, humid southerly flow, and weak surface
winds. Hazards today include elevated heat, limited to elevated
localized flooding, and limited lightning.

A much wetter and more unstable pattern will develop as the trough
deepens and moisture increases in multiple waves, while mid level
500 mb temperatures cool to below normal, creating favorable
conditions for deep convection. Low level winds will remain light
and southwesterly, slowing storm motion and allowing showers and
thunderstorms to persist. Overnight activity will favor the southern
and western coasts, while each afternoon storms will again push
toward eastern and northeastern Puerto Rico, increasing the flood
threat for the San Juan metro each day. Heat will remain a daily
concern due to very warm low level temperatures and humid southerly
flow. Hazards will remain in the same order, with heat as the main
concern, followed by flooding and lightning, and both heat and
flooding trending higher late in the week. The greatest impacts are
expected late Thursday through Friday as moisture, instability, and
slow moving storms peak.


.LONG TERM...Saturday through Wednesday..

As mentioned in previous discussion the wet and unstable weather
conditions are forecast to persist through the weekend, with
gradual improvement early in the workweek. On Saturday, winds
should remain light, shifting from the southwest under the
influence of a surface high pressure system over the central
Atlantic and a broad polar trough. This pattern will continue to
pool the remnants of a frontal boundary and abundant tropical
moisture over the region. Based on the latest model guidance
Precipitable Water (PWAT) values will remain seasonal to above
normals (2.00 – 2.30 inches) for this time of the year.
Additionally, the polar trough reflected at the mid to upper
levels may deepen enough to cool 500 mb temperatures (-7 to -8
degrees Celsius), enhancing instability and supporting deep
convection. The Galvez-Davison Index (GDI) also suggests potential
for isolated to scattered thunderstorms through at least Sunday.
As a result, showers and thunderstorms are expected to remain
frequent, affecting mainly windward sections during nighttime and
early morning hours, while afternoon convection develops across
the interior and western mountains of Puerto Rico. Given the
enough moisture and unstable conditions, lightning and localized
flooding threats will range from limited to elevated through the
weekend.

By late Monday, conditions should begin to improve as a drier air
mass filters into the region. Model guidance indicates a decrease
in PWAT values to around 1.7 – 1.9 inches, though variability
remains high among ensemble members due to a tropical wave
projected to pass south of the forecast area. Despite this,
daytime heating, local effects, and residual moisture will still
promote afternoon shower and thunderstorm development, mainly
across the western and northwestern portions of Puerto Rico,
though the flooding threat should remain limited.

Tuesday and Wednesday are expected to feature fewer showers and
more stable conditions overall, with moisture levels fluctuating
around seasonal values. Isolated convection may still occur each
afternoon over the western interior due to local effects, but
widespread activity is not anticipated.

&&

.AVIATION...
(06Z TAF)

Var WX. Early trade SHRA mainly USVI. Aftn SHRA/TSRA shifts N–NE.
PR terminals (esp TJSJ) SHRA/TSRA likely 15/16–22Z with brief
MVFR/IFR VIS/CIG in heavier cells. TJBQ also impacted. USVI SHRA
on/off, more at night. Most activity fades aft sunset, but may
linger TJSJ/TJBQ. Winds LGT/VRB overnight, bcmg S 8–12 kt with
strg sea-breeze var, then LGT/VRB aft 22Z. Greatest ops impacts:
TJSJ 15/16–22Z.

&&

.MARINE...

Winds will continue to become light to gentle from the south-
southwest from today onwards. The approaching frontal boundary
will induce a pre-frontal trough for the second half of the
workweek, increasing shower and thunderstorm activity across the
regional waters and passages. Pulses of a long period easterly swell
will reach the local exposed waters Thursday into Friday. Pulses of a
long period northerly swell will reach the Atlantic waters and
passages from Friday into early next week.

&&

.BEACH FORECAST...

There is a moderate risk of rip currents along the north and
eastern coast of Puerto Rico, with a low risk across the same
areas tomorrow. However, a long period northerly swell will
increase the threat of life- threatening rip currents along the
northern and eastern coast of Puerto Rico, and the US Virgin
Islands to moderate on Friday once again.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
532 AM AST Thu Oct 16 2025

.KEY MESSAGES...

* For Puerto Rico, limited to elevated/moderate flood risk, with
the heaviest along northeastern PR. Therefore, ponding of water
of road and poorly drained areas is forecast.

* For the U.S. Virgin Islands, shower and thunderstorm activity is
expected to increase through Saturday.

* A gradual improvement in weather conditions is forecast by late
Monday as a drier airmass moves across the islands.

* A northerly swell will lead to deteriorating marine and coastal
conditions by the end of the weekend into next week. Stay
updated for updates regarding the issuance of statement or
advisories.


&&

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

During the night, GOES-16 satellite data and the Geostationary
Lightning Mapper indicated strong thunderstorms with frequent
lightning associated with an advancing frontal boundary over the
northwestern Atlantic waters. These storms later moved across the
northwestern municipalities of Puerto Rico. Several Special Marine
Warnings were issued for the affected regional waters, and a Marine
Weather Statement remained in effect for the offshore Atlantic
waters through the morning hours. In addition, Flood Advisories were
issued for western/northwestern and southwestern municipalities due
to periods of heavy rainfall that caused minor flooding and ponding
of water on roadways. The storms also produced gusty winds and
frequent lightning, with several stations reporting wind gusts in
the upper 20s to low 30s mph. A weather station in Aguada even
recorded a peak wind gust of 40 mph. For the remainder of the
morning hours, as the frontal boundary continues to move southward,
additional showers and isolated thunderstorms are expected across
northern sections of Puerto Rico, but likely will remain over the
water for the most part.

A polar trough and its associated frontal boundary will remain the
dominant features influencing local weather through the end of the
week and into the weekend. The pre-frontal trough, currently located
across the region, along with the frontal boundary situated just
north of the area, is expected to stall and linger through Saturday,
maintaining a moist and unstable environment. Model guidance
indicates that precipitable water values (PWAT) will remain above
climatological normals, fluctuating between 1.8 and 2.2 inches.
These elevated moisture levels will support periods of widespread
showers and isolated thunderstorms. Upper-level instability is
expected to persist as 250 mb height fields remain near or below
normal, while 500 mb temperatures hover around -7 to -8C, further
enhancing convective potential.

During the afternoon, a prevailing southerly component will favor
moisture convergence across the northern and northeastern portions
of Puerto Rico. Scattered to numerous showers and thunderstorms are
expected, particularly over the interior and northern/northeastern
municipalities, with activity gradually diminishing into the
evening. However, the extent and intensity of afternoon convection
will depend on cloud coverage; if cloudiness persists through the
morning and early afternoon, it could limit surface heating and
hinder convective development. Localized flooding, ponding of water
on roadways, and reduced visibility in heavy rain remain possible.

On Friday and Saturday, the frontal boundary will remain nearly
stationary as upper-level troughing deepens. Persistent moisture and
continued instability will support another round of showers and
thunderstorms, particularly across the interior and north-central
areas. Model guidance indicates elevated relative humidity in the
700-500 mb and 850-700 mb layers, along with relatively steep lapse
rates within these levels, maintaining favorable conditions for
convection.

A limited to elevated flooding threat will persist through the short-
term period, with the interior, northern, and northeastern portions
of Puerto Rico, as well as the northern U.S. Virgin Islands,
potentially experiencing the brunt of the activity. Urban and small
stream flooding will remain possible, along with frequent lightning
and gusty winds accompanying the strongest thunderstorms. Although
periods of unsettled weather are expected, activity will not be
constant throughout the period, and intervals of calmer conditions
are also anticipated. Residents are encouraged to stay tuned for
updates regarding any advisories, warnings, or statements that may
become necessary.

Temperatures at 925 mb remain above normal today, indicating
continued warm and humid conditions, particularly across coastal and
urban areas. However, extensive cloud cover could limit surface
heating, which in turn may reduce the overall heat threat. Weather
conditions will continue to be monitored, and if significant cloud
clearing occurs during the morning hours, Heat Advisories may be
required and will be issued accordingly. A downward trend in the
heat threat is expected through the weekend as the frontal boundary
lingers and cloud cover persists.

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

Wet and unstable weather conditions are expected to persist through at
least Monday as the remnants of a frontal boundary and its
associated moisture continue to influence the local area. This
pattern will result in increased moisture and instability,
supporting periods of showers and thunderstorm activity across the
region. The latest model guidance indicates deep-layer moisture
extending from the surface to the mid-levels, maintaining a moist
environment favorable for convection. As a result, frequent
showers and thunderstorms are expected, with activity affecting
mainly the windward and coastal sections during the nighttime and
early morning hours, and developing across the interior and
western portions of Puerto Rico during the afternoon hours. Given
the abundant moisture and instability, lightning and localized
flooding threats will range from limited to elevated, particularly
across portions of Puerto Rico through Monday.

By late Monday, a gradual improvement in weather conditions is expected
as drier air filters into the region. For Tuesday and Wednesday,
weather conditions should become more stable overall, with
moisture levels fluctuating around seasonal to below values for
this time of the year. Despite the drying trend, residual moisture
and local effects combined with daytime heating will still
promote isolated to scattered afternoon showers, mainly over the
interior and western Puerto Rico. The flooding threat during this
period should remain limited to none.

However, by the later part of the workweek, model guidance shows a
gradual increase in moisture and shower activity as a tropical
wave or potential tropical system moves south of the region. Until
then, fair weather and limited convection are expected, with
isolated afternoon showers possible over the western interior due
to local and diurnal effects.

We urge citizens and visitors to continue to monitor the forecast
for any significant changes.

&&

.AVIATION...
(06Z TAFS)

A stalled frontal boundary over and N of the area could result at
times in BKN cigs with -SHRA/ISOLD TSRA across the region this
morning, where TEMPO MVFR conds are possible. After 18Z, SHRA/ISOLD
TSRA are expected to develop over the interior and move toward the N
and NE coastal terminals due to diurnal heating and local effects,
leading to brief MVFR conds and MTN OBSC. SFC winds LGT/VRB less
than 10 kt, except near TSRA/SHRA where gusty/vrb winds may occur.

&&

.MARINE...

The approaching frontal boundary will continue to induce a pre-
frontal trough for the rest of the workweek, increasing shower and
thunderstorm activity across the regional waters and passages.
This will also increase wind speed from time to time with the
heaviest thunderstorm activity. Pulses of a long period easterly
swell will reach the local exposed waters by Thursday into Friday.
Pulses of another long period northerly swell associated to low
pressure system over the northwestern Atlantic waters will reach
the Offshore and local Atlantic waters and passages late in the
weekend into the upcoming workweek.

&&

.BEACH FORECAST...

Low rip current risk will prevail today. However, a moderate rip
current risk will return by Friday and coastal conditions will
gradually deteriorate as pulses of another long period northerly
swell increases the threat of life-threatening rip currents along
the west, north, and eastern beaches of the islands. High surf
conditions and minor coastal flooding are likely on Sunday and
Monday as the northerly swell builds seas between 6 and 8 feet
around 12 to 14 seconds, which translates to breaking waves
between 10 and 15 feet.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Fri Oct 17 2025

.KEY MESSAGES...

* For Puerto Rico, there is a limited to elevated flood threat,
with the heaviest showers expected through Sunday.

* For the U.S. Virgin Islands, shower and thunderstorm activity is
forecast to continue throughout the day. Therefore limited
flooding risk is forecast for the USVI.

* A gradual improvement in weather conditions is forecast by late
Monday as a drier airmass moves across the islands.

* Northerly swells will lead to deteriorating seas and life-
threatening rip currents during the weekend. Small craft
advisories, rip current/high surf/coastal flood statements will
be required, particularly from Sunday through Tuesday.

&&

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

During the night, a nearly stationary frontal boundary continued to
interact with deep tropical moisture over the northeastern
Caribbean, resulting in widespread heavy showers and numerous
thunderstorms, particularly across the Caribbean waters and the
Anegada Passage. Some of these storms extended into portions of St.
Croix, producing frequent lightning, gusty winds, and periods of
heavy rainfall. Several Special Marine Warnings were issued for the
affected waters, and a Special Weather Statement was issued for St.
Croix due to hazardous lightning and strong wind gusts.

For today, Friday, the frontal system will remain quasi-stationary
over the area, while a polar trough aloft maintains favorable
conditions for convection. Low-level winds will generally be from
the south-southwest, promoting moisture convergence across the
interior, north-central, and northeastern Puerto Rico this
afternoon, with localized flooding possible in these areas.
Additional impacts could extend into Vieques, Culebra, and portions
of the U.S. Virgin Islands. Model guidance indicates precipitable
water values (PWAT) near or slightly above climatological normals,
exceeding 2.0 inches. These moisture levels, combined with steep
lapse rates between 700-500 mb, will support strong to isolated near
severe convection during the afternoon and evening hours.

On Saturday, the frontal boundary and its associated trough aloft
will begin to weaken but linger over or slightly north of the area,
maintaining a moist and unstable pattern. Winds will veer more
southerly, favoring afternoon convection mainly across the interior
and north-central Puerto Rico. Although large-scale forcing will
gradually diminish, sufficient moisture and instability will remain
to support another round of showers and isolated thunderstorms.
Ponding of water on roadways and localized flooding will remain
possible, particularly where heavier downpours persist. Frequent
lightning and strong, gusty winds will be possible with the most
intense thunderstorms.

By Sunday, the remnants of the frontal system will shift farther
north as the polar trough weakens and ridging begins to build from
the east. Winds will become more southeasterly, promoting a gradual
drying trend, especially across the U.S. Virgin Islands and eastern
Puerto Rico. However, diurnal heating and lingering low-level
moisture will still trigger afternoon convection across the
northwestern quadrant of Puerto Rico, where the flood threat will be
most concentrated.

The presence of cloud cover due to the stationary front could limit
surface heating, which in turn may reduce the overall heat threat.
Weather conditions will continue to be monitored, and if significant
cloud clearing occurs during the morning hours, Heat Advisories may
be required and will be issued accordingly. A downward trend in the
heat threat is expected through the weekend.


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

A gradual improvement in weather conditions is expected beginning
late Monday as a drier air mass filters across Puerto Rico and
the U.S. Virgin Islands. Model guidance indicates precipitable
water (PWAT) values decreasing to around or slightly below normal
levels for this time of the year, while mid-level relative
humidity also trends near normal. This drier and more stable air
mass will promote a noticeable reduction in the frequency of
showers and thunderstorm activity across the region. However,
residual low-level moisture, combined with local effects and
daytime heating, will still result in isolated to scattered
afternoon showers, mainly across the interior and western Puerto
Rico each day. Overall, the flooding threat should remain limited
to none through midweek. This weather pattern should continue
through midweek.

By Thursday, model guidance suggests a gradual increase in PW,
relative humidity, and wind speed as a tropical wave or possible
tropical system moves near the local area. This will likely lead
to a return of wetter conditions by the latter part of the
workweek into the weekend. At this time, the National Hurricane
Center forecasts a 10 percent chance of development in the next 48
hours and a 30 percent chance within the next 7 days.

Regardless, residents and visitors are encouraged to continue
monitoring the latest forecasts for any significant changes in
conditions.

&&

.AVIATION...
(06Z TAFS)

A nearly stationary front ovr and to the N of the area will continue
to generate SHRA/TSRA ovr the waters. Mainly VFR thru prd. However,
low VIS/CIGs could result in brief MVFR/IFR in SHRA/TSRA ovr TAF
sites. Under S-SW steering winds, intermittent SHRA/TSRA may affect
TJPS/TJSJ/TIST with aftn convection. Sfc wnd S-SW 8-14 kt with brief
gusts 25-30 kt nr TSRA, bcmg lgt/vrb aft 23Z. WSW winds 10-20 kt blo
FL050 per 17/00Z sounding.

&&

.MARINE...

The nearby stationary boundary will continue to promote shower and
thunderstorm activity across the regional waters and passages through
the weekend. This will also increase wind speed from time to time
with the heaviest thunderstorm activity. Pulses of a long period
easterly swell will continue to reach the local exposed waters
through tonight. Another but stronger long period northerly swell,
associated to low pressure system over the northwestern Atlantic
waters, is expected to reach the Atlantic waters and local passages
around Sunday into the upcoming workweek. As a result, hazardous
marine conditions are anticipated. Please, continue to monitor the
forecast updates over the coming days.

&&

.BEACH FORECAST...

Pulses of long period northerly swells will gradually increase the
threat of life-threatening rip currents along the west, north,
and eastern beaches of the islands during the weekend. High surf
conditions and minor coastal flooding are likely by Sunday as the
northerly swell builds seas between 6 and 8 feet around 12 to 14
seconds, which translates to breaking waves between 10 and 15
feet. Overall, dangerous swimming conditions, minor beach
erosion, and life-threatening rip currents are expected from this
weekend into early next week.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
534 AM AST Sat Oct 18 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...

* For Puerto Rico, there is a limited to elevated flood threat,
due to afternoon thunderstorms throughout the weekend.

* For the U.S. Virgin Islands, a limited flooding risk and
lightning activity across the islands from time to time.

* Hazardous marine and coastal conditions due to dangerous
breaking waves and life-threatening rip currents from NOW into
the upcoming workweek for the north-facing beaches of PR and
the USVI.

&&

.SHORT TERM...Today through Monday...
Issued at 523 AM AST Sat Oct 18 2025

The remnants of a frontal boundary interacting with deep tropical
moisture continue to promote heavy showers and strong thunderstorms
across portions of the local area. Overnight, a strong thunderstorm
developed over St. Thomas, prompting the issuance of a Special
Weather Statement and a Flash Flood Warning. Radar estimates
indicated rainfall totals up to 2.5 inches over the island.
Elsewhere, scattered thunderstorms developed over the Atlantic and
Caribbean waters and Mona Passage, producing frequent lightning and
locally heavy rainfall, resulting in Marine Weather Statements and
Special Marine Warnings.

Today, southerly low-level winds will favor afternoon convection
developing over the interior and moving northward toward the north-
central municipalities of Puerto Rico. The light steering flow will
support slow-moving thunderstorms, enhancing the potential for urban
and small-stream flooding. The most intense thunderstorms could
produce frequent lightning, gusty winds, and ponding of water on
roadways.

The GFS-sounding continues to depict precipitable water values
between 2.0 and 2.2 inches, steep 700-500 mb lapse rates, and 850-
700 mb relative humidity exceeding 70 percent, confirming a very
moist and unstable column consistent with the ongoing convective
activity.

By Sunday, winds will increase slightly and shift to the southeast
as the remnants of the front lift northward. A gradual drying trend
is expected as mid-level moisture decreases, but sufficient low-
level moisture will linger to support scattered afternoon showers
and isolated thunderstorms, mainly across the interior and
northwestern Puerto Rico. Although a tropical wave will move near
the region, its deepest moisture should remain south of the islands.
Even so, sea-breeze convergence, orographic lift, and favorable
upper-level dynamics (500 mb temperatures near −6C, moderate lapse
rates) will sustain occasional strong convection capable of
producing frequent lightning, gusty winds, and localized flooding.

Additionally, having the remnants of the front north of the area,
combined with the tropical wave passing south, could result in an
increase in low-level convergence. A similar weather pattern is
expected on Monday as another tropical wave passes south of the
forecast area, supporting another round of afternoon showers and
thunderstorms, particularly across the interior and western sections
of Puerto Rico. While the bulk of the moisture will remain south of
the islands, localized flooding, gusty winds, and dangerous cloud-to-
ground lightning will continue to be concerns.

&&

.LONG TERM...Tuesday through Friday...
Issued at 523 AM AST Sat Oct 18 2025

Tuesday is expected to be the driest and most stable day of the
long-term period, as model guidance indicates precipitable water (PWAT)
values decreasing to around or slightly below normal for this
time of year. This drier and more stable air mass will help
suppress widespread convective activity, leading to mostly fair
weather conditions. However, localized afternoon showers cannot be
ruled out, mainly across the interior and western sections of
Puerto Rico due to daytime heating and local effects. Flooding
potential remains minimal through this period.

Wednesday will still be a generally fair day, with conditions remaining
relatively stable during the morning hours. However, as the day
progresses, a gradual increase in moisture content and mid-level
humidity is expected, resulting in a higher potential for
afternoon showers across portions of the interior and western
Puerto Rico. This trend marks the beginning of a slow transition
toward a wetter pattern.

From Thursday onward, the forecast becomes increasingly dependent on
the evolution of a system currently being monitored by the
National Hurricane Center (NHC). At this time, the long-term
forecast leans toward the GFS solution, which depicts a wetter
pattern developing from Thursday into the weekend. The NHC
currently assigns this disturbance a 0 percent chance of
development within the next 48 hours and a 30 percent chance
within the next 7 days.

It is important to note that forecast confidence decreases
significantly after Thursday, as there remains high uncertainty and
notable discrepancies among model solutions regarding the
development and possible impact for Puerto Rico and the U.S.
Virgin Islands. Regardless of development, an increase in moisture
and instability could lead to wetter and potentially unsettled
conditions late in the week.

Residents and visitors are advised to monitor the latest forecasts
and updates from the National Weather Service and the National
Hurricane Center for any significant changes.

&&

.AVIATION...
(06Z TAFS)

SHRA/TSRA over regional waters will cont through early mrng, with
brief MVFR/IFR conds psbl near coastal terminals, particularly
ovr TIST/TISX. Aft 15Z, SHRA/TSRA will redevelop ovr the interior
and N- CNTRL PR due to sea breeze conv and ample low-lvl moisture.
Expect VCTS at TJSJ, TJBQ, and TJPS by late mrng thru aftn, with
brief TSRA and reduced VIS/CIGs psbl mainly btw 17-22Z. VFR conds
should prevail at most terminals ovrngt. Winds lgt/vrb bcmg S
10-12KT aft 14Z with higher gusts, diminishing aft 22Z.

&&

.MARINE...
Issued at 523 AM AST Sat Oct 18 2025

The nearby stationary boundary will continue to promote shower and
thunderstorm activity across the regional waters and passages
through at least today. A long period northerly swell, associated to
low pressure system over the northwestern Atlantic waters, is
expected to reach the Atlantic waters and local passages today into
Sunday through the upcoming workweek. As a result, hazardous marine
conditions are anticipated. Please, continue to monitor the forecast
updates over the coming days.

&&

.BEACH FORECAST...
Issued at 523 AM AST Sat Oct 18 2025

Due to the presence of an incoming long period northerly swell
a HIGH rip current risk was issued for the northern, western, and
eastern coast of PR and Culebra through the upcoming workweek. This
swell will create dangerous breaking waves and life- threatening
rip currents along the west, north, and eastern beaches of the
islands.

High surf conditions and minor coastal flooding are likely by
Sunday, and will possibly extend into the early part of next week.
Overall, dangerous swimming conditions, minor beach erosion, and
life-threatening rip currents are expected from this weekend into
early next week.

[cycloneye]

Area Forecast Discussion...DELAYED
National Weather Service San Juan PR
529 AM AST Sun Oct 19 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...

* Dangerous beach and ocean conditions today: Large breaking waves
and strong rip currents will make swimming and small craft
operations hazardous along the north and east coasts of Puerto
Rico, Culebra.

* Wetter weather later this week: Moist air linked to a tropical
disturbance in the Caribbean could bring periods of heavy rain and
thunderstorms from Wednesday through Saturday.

* Potential for flooding and gusty winds: Heavy downpours, localized
flooding, and windy, squally conditions are possible later this
week, depending on how close and how strong Invest 98L becomes.
Stay alert and monitor forecast updates.

* U.S. Virgin Islands: Dangerous rip currents are expected along
north- and east-facing beaches tonight, with wetter and windier
conditions possible later this week as tropical moisture
increases over the area.

&&

.SHORT TERM...
(Today through Tuesday)
Issued at 523 AM AST Sun Oct 19 2025

Overnight conditions remained relatively calm, although bands of
showers developed across the Atlantic waters, Caribbean waters, and
the Mona Passage. Some of these showers did produce occasional
lightning, mainly within the heaviest rainfall. The temperatures
along the coastal and urban areas remained in the upper 70s to low
80s, while along the mountains they stayed in the upper 60s to low
70s degrees Fahrenheits. Winds were light and variable.

During the first half of the day, winds will be east-southeasterly,
becoming more easterly during the afternoon as the remnants of a
frontal boundary continue to move away from the area. The presence
of the remnants will allow the thunderstorm activity to develop
from time to time across the waters. Precipitable water model
guidance indicates a slight drying trend today, with mid-level
relative humidity near normal values for this time of year and 500
mb temperatures around -6 degrees Celsius. Even so, residual low-
level moisture, in combination with local effects and diurnal
heating, will promote afternoon convection. Expect scattered
showers and isolated thunderstorms, particularly during the
afternoon hours, some of which could produce frequent lightning,
gusty winds, and localized flooding, mainly where sea-breeze
convergence and orographic lift are strongest.

A similar weather pattern is expected on Monday but with a tropical
wave to the south of Puerto Rico and the US Virgin Islands. This
setup will sustain another round of afternoon showers and
thunderstorms, particularly across the interior and western sections
of Puerto Rico. While the bulk of the tropical moisture will remain
south of the islands, localized flooding, gusty winds, and dangerous
cloud-to-ground lightning will remain possible with stronger
convection.

By Tuesday, a drier and more stable air mass will settle over the
region, while the tropical wave remains south of the area. This will
result in limited shower activity, with only isolated brief showers
expected during the morning hours. The rest of the day will feature
mostly fair skies, light winds, and stable conditions, making
Tuesday the driest and most stable day of the short-term period.
However, by Tuesday night into midweek, conditions are forecast to
gradually become wetter as a broad area of low pressure, currently,
being monitored by the National Hurricane Center and given a 50
percent chance of development over the next 7 days and 10 percent
within the next 48 hours, moves closer to the region, bringing
increasing tropical moisture and the potential for unsettled weather
later in the week.

At this time we encourage, citizens and visitors to continue
monitoring the forecast from the National Hurricane Center and your
local National Weather Service fro any changes in the forecast.

&&

.LONG TERM...
(Wednesday through Sunday)
Issued at 523 AM AST Sun Oct 19 2025

The long-term period continues to highlight an increasingly
unsettled and wet weather pattern across Puerto Rico and the U.S.
Virgin Islands, associated with a deep surge of tropical moisture
linked to Invest 98L, a tropical wave currently being monitored by
the National Hurricane Center. The latest NHC outlook indicates that
environmental conditions may become more conducive for gradual
development as the system moves westward across the Caribbean, with
a medium (50%) chance of tropical cyclone formation within seven
days.

Deterministic guidance from the 19/00Z GFS run remains consistent
with previous cycles, showing a strong tropical cyclone developing
over the central Caribbean, interacting with the Central American
Gyre (CAG). In this scenario, the system is steered northeastward by
the CAG, enhancing a southerly flow that advects deep tropical
moisture into the local area during the latter half of the week.
Ensemble guidance and other global models, including the ECMWF,
support a similar broad moist environment, though differ in system
track and timing, with many solutions stalling the disturbance over
the Caribbean waters.

In terms of dynamics aloft, the GFS soundings indicate a very moist
column, with precipitable water values exceeding 2.5 inches (above
the 90th climatological percentile, well above normal for this time
of year) from Wednesday through the weekend. Relative humidity
values near saturation between 850-500 mb confirm a deep moisture
layer, supporting scattered to widespread convection. However,
warming mid-level temperatures and weak lapse rates suggest limited
instability aloft.

The latest model solutions also marked an increase in low-level wind
speeds consistent with the approach of a strong low-level
circulation or a tight pressure gradient. This supports the
potential for gusty, squally conditions, especially over coastal and
elevated areas. The ECMWF Extreme Forecast Index (EFI) signal
enhanced probabilities for excessive rainfall and strong wind gusts
from mid- to late-week, particularly for the western half of the
CWA, consistent with the deterministic and ensemble trends.

Given the projected deep tropical moisture plume, gusty southerly
winds, and potential for squally weather, the main threats during
this period include urban and flash flooding, especially in low-
lying or poor-drainage areas, localized river rises due to prolonged
rainfall, landslides and rockfalls in areas of steep terrain and
saturated soils, and squally conditions with strong gusts
accompanying showers and thunderstorms.

Nevertheless, forecast confidence remains low, as the eventual
track, intensity, and proximity of Invest 98L to the forecast area
will dictate the magnitude and timing of local impacts. A more
organized, slower-moving, or closer system could substantially
increase rainfall totals and wind hazards, while a weaker, faster-
moving, or more distant disturbance would limit these effects.

&&

.AVIATION...
(06Z TAFS)
Issued at 523 AM AST Sun Oct 19 2025

VFR conditions will prevail across all terminals this morning
with light and variable winds. Aft convt is anticipated mainly
TJBQ after 19/17Z across TJBQ and TJPS. Convection should
dissipate after 22Z, leading to improving conditions and
prevailing VFR overnight. Some bands of showers may linger over
the TAF sites. Winds will become light and variable overnight with
land-breeze effects along coastal areas. Overall, aviation
conditions will remain mostly favorable outside.

&&

.MARINE...
Issued at 523 AM AST Sun Oct 19 2025

The remnants of a frontal boundary will continue move north promoting
shower and thunderstorm activity across the offshore Atlantic
waters at times. A long period northerly swell will continue to
spread across the local Atlantic waters and passages today, with
hazardous marine conditions for small craft expected by early this
morning. Please, continue to monitor the forecast updates over
the coming days.

&&

.BEACH FORECAST...
Issued at 523 AM AST Sun Oct 19 2025

A high risk of rip currents is in effect along the north- and east-
facing beaches of Puerto Rico and Culebra as a long-period northerly
swell moves across the northern regional waters. These swells will
gradually increase in height through this afternoon, leading to
hazardous surf conditions with breaking waves of up to 12 feet along
exposed beaches. For this reason, a High Surf Advisory is also in
effect. Additional High Rip Current Risk Statements will likely be
issued throughout the day for the U.S. Virgin Islands. Beachgoers
and visitors are urged to exercise extreme caution, heed local
advisories, and avoid swimming in high-risk areas, as life-
threatening rip currents are expected to persist through early this
week before gradually improving.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST Tue Oct 21 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...

* Invest AL98 located well south over the Caribbean s forecast
to become a tropical storm later today. This system is
resulting in cloudiness and showers across the islands.

* A variable weather pattern is forecast for today with mostly
cloudy skies, followed by some isolated brief afternoon
showers.

* Uncertainty is present in the forecast due to different
solutions of the final trajectory of the now Invest 98L, stay
tuned for further updates.

* For the U.S. Virgin islands, a mostly cloudy day is forecast
along the islands with maximum temperatures in the mid to upper 80s.

&&

.SHORT TERM...Today through Thursday...
Issued at 450 AM AST Tue Oct 21 2025

Today through Thursday...

Mostly cloudy skies were observed across the islands during the
early morning hours. Thunderstorms with periods of heavy showers and
gusty winds moved across portions of southern and eastern PR, and
across St. Croix. Rainfall accumulations up to 2.50 inches were
reported in southern PR. Minimum temperatures were from the upper-
70s to low 80s across the lower elevations of the islands to the mid-
60s and mid-70s across the higher elevations of Puerto Rico. The
wind was from the southeast at 10 to 15 mph with stronger gusts at
times.

Invest AL98, well south of the area, will influence the local
weather conditions through the rest of the short term period. Global
model guidance suggest that the system is expected to develop into a
tropical storm during the next day or so, while moving slowly into
the central Caribbean Sea. This will continue to promote a moist
southeasterly wind flow across the local area, and external
rainbands associated to the system could move over portions of the
Caribbean waters and over the islands, particularly today. At least
through Wednesday, hi-res model data suggest that the southern
slopes of PR, as well as areas in eastern PR, should receive the
highest rainfall amounts, with isolated amounts up to 2 inches each
day. Across the USVI, up to 1 inch is possible, and mainly in St.
Croix, as a drier air mass is expected to linger to our northeast,
and should inhibit widespread rainfall mainly across the northern
islands. Having said that, latest Total Precipitable Water imagery
indicated that this drier air mass has already arrived, and that the
precipitable water content (PWAT) moving into the Anegada Passage is
closer to 1.55 inches, compared to over 2.35 inches between the
local Caribbean waters and the Mona Passage. If the system slows
down, this higher moisture content will continue to build and stream
over the same area for the next day or so, supporting the wetter
forecast for south/east PR.

On Thursday, a tropical wave currently over the central Atlantic is
expected to reach the eastern Caribbean, enhancing the overall
moisture content over the area. The precipitable water content is
expected to peak by then, btw 2-2.25 inches, which suggest a wetter
scenario for the USVI, and across PR in general.

&&

.LONG TERM...Friday through Tuesday...
Issued at 450 AM AST Tue Oct 21 2025

The long-term forecast remains uncertain due to the different
model solutions for Invest 98L in the Caribbean. The GFS guidance
indicates that the tropical system will move northward near Haiti,
pushing most of the deep-layer moisture across the islands. This
motion would weaken the pressure gradient and allow winds to veer
more from the south-southwest by the upcoming weekend. In
contrast, the European model (ECMWF) suggests the tropical system
will move just south of Jamaica around the same time. Under this
scenario, the islands would still remain under a fair amount of
tropical moisture, though not as high as what the GFS suggests.

Given these discrepancies, confidence in the forecast from Friday
through Monday remains low to moderate. For now, the forecast
aligns with the National Hurricane Center forecast, calling for a
variable and wet pattern with afternoon showers and a 40–70
percent chance of rain each day. The strongest showers are
forecast from Friday into Saturday, as some instability would be
present in the area, allowing 500 MB temperatures of -6 degrees.
Additionally, precipitable water values ranging between 1.9 and
2.3 inches, well above climatological normals, support enhanced
convective potential across the southern coastal plains and the
interior sections due to the south wind flow at the 0-3 KM.

Now, there is a worst-case scenario if the system develops and
moves northeastward as the GFS suggests. These solutions will lead
to a considerable surge in moisture exceeding two standard
deviations of the typical climatological values. Additionally,
external bands of the future tropical storm could leave the
circulation and reach the islands, producing gusty winds and
strong thunderstorms during that period. Therefore, residents and
visitors should continue to monitor updates on Invest 98L, which
is expected to become a tropical storm later today.


&&

.AVIATION...
(06Z TAFS)
Issued at 450 AM AST Tue Oct 21 2025

Mainly VFR conds are expected to prevail across all terminals
thru the fcst period. However, SHRA/TSRA expected to develop from
the Caribbean waters into the local area at times under
southeasterly steering winds, associated to a broad surface low
well south of the islands. This should impact mainly TJPS at times
with tempo MVFR conds. Elsewhere, mostly VCSH expected, however,
there is a slight chance of VCTS early this morning at TISX/TJSJ.
ESE winds 12-16 kt with gusts up to 22-26 kt aft 13z.

&&

.MARINE...
Issued at 450 AM AST Tue Oct 21 2025

Hazardous marine conditions will persist along the northern local
and exposed waters due to pulses of a northerly swell that
continues today. Therefore, seas will continue from 7 to 9 feet
along the offshore Atlantic waters and up to 7 feet across the
coastal waters and local passages. As a result, small craft
advisories continue in effect along the aforementioned waters for
the entire day. An improvement is forecast from later tonight
along the islands as the northwesterly swell diminishes over the
seas. Showers and thunderstorms, a product of the Invest 98L now
located more than 300 miles southwest of the islands, will
continue to result in localized hazardous marine conditions across
the Caribbean waters and the Mona Passage during the day. Mariners
are urged to stay protected during the day across these waters.

&&

.BEACH FORECAST...
Issued at 450 AM AST Tue Oct 21 2025

Hazardous coastal conditions will persist along the northern
beaches and exposed Atlantic waters due to the arrival of several
pulses of a long-period northerly swell through tonight. As a
result, breaking waves of 10 to 11 feet will continue to impact
the northern exposed coastlines of Puerto Rico, Culebra, and the
northern U.S. Virgin Islands. These conditions will maintain a
life-threatening rip current risk for beachgoers. A High Surf
Advisory remains in effect until 6 PM AST, and a High Rip Current
Risk continues through at least Tuesday evening for the north-
facing beaches. Coastal residents and visitors are urged to stay
out of the water and away from the shoreline due to the dangerous
surf and strong currents.

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
438 AM AST Wed Oct 22 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...

* For today, showers and thunderstorms will lead to flooding in
urban areas, roads, small streams, and washes across southern
municipalities, as well as some eastern and western areas.

* High uncertainty remains in the upcoming forecast due to
differing solutions among global model guidance regarding
Melissa’s trajectory.

* A fading northerly swell will continue to produce hazardous marine
conditions across the offshore Atlantic waters and local
passages, along with hazardous coastal conditions featuring
large breaking waves and dangerous rip currents.

* For the U.S. Virgin Islands, a variable weather pattern will
persist, with brief passing showers potentially causing minor
flooding in low-lying urban areas.

&&

.SHORT TERM...Today through Friday...
Issued at 412 AM AST Wed Oct 22 2025

Cloudy skies prevailed across the islands during the early morning
hours. Showers and isolated thunderstorms developed between the
eastern waters of Puerto Rico and the U.S. Virgin Islands. The
Doppler radar estimated up to 0.25 inches across the eastern
interior to just over an inch in eastern PR. Across the USVI,
accumulations were less than 0.10 inches. Minimum temperatures
ranged from the upper-70s to low 80s across the lower elevations of
the islands, and from the mid-60s to mid-70s across the higher
elevations of Puerto Rico. The wind was from the east to southeast
at 8 to 16 mph with gusts between 26 and 33 mph observed with the
showers.

Tropical Storm Melissa, located over the central Caribbean Sea, will
continue to promote higher moisture content over the Caribbean Sea
during the next few days, while moderate east to southeasterly
trades prevail across the area under the influence of TS Melissa and
from a weak surface high pressure building from the central
Atlantic. Embedded in this flow, higher amounts of precipitable
water content will move from the tropical Atlantic into the eastern
Caribbean, maintaining an overall wet pattern through the short-term
period. The general rainfall forecast over the next three days
remains the same, with total accumulations of 2 to 4 inches across
the CWA. Global and hi-res model guidance continues to suggest the
highest potential for rainfall along the southern and eastern half
of PR, particularly from Thursday through Friday. For the USVI, an
advective weather pattern will persist, but as fast-moving showers
are expected, the total rainfall accumulations should remain under
the lower end of the forecast.

Overall, periods of heavy rainfall with localized flooding and gusty
winds can be expected across the islands through the short-term
period. There is no significant change to the temperature forecast,
as cloudy skies should limit the heat-related impacts during the
day, while minimum temperatures remain a few degrees higher than
usual.

&&

.LONG TERM...Saturday through Wednesday...
Issued at 412 AM AST Wed Oct 22 2025

High uncertainty persists in the long-term period across the
islands. Global guidance models have not shown significant changes
in their solutions from Saturday through the upcoming workweek due
to the proximity of what is now Tropical Storm Melissa. The GFS
guidance continues to indicate that the tropical system will move
northward into Hispaniola, keeping the islands under deep-layer
moisture with precipitable water values between 2.0 and 2.3
inches. This pattern in the GFS model will also favor a weak
pressure gradient and veering winds from 0–3 km, allowing mostly
southerly winds on Saturday into Sunday, shifting more toward the
west-southwest on Monday through Wednesday across the islands. In
contrast, the European model (ECMWF) suggests Tropical Storm
Melissa moving northeastward between Jamaica and the western tip
of Haiti. This solution is quite similar to the official
trajectory from the National Hurricane Center, which keeps Melissa
moving slowly during the next several days. Similar to
yesterday’s forecast, given these discrepancies, confidence in the
forecast from Saturday through Wednesday remains low to moderate.

For now, the forecast aligns with the National Hurricane Center’s
outlook, calling for a variable and wet pattern with afternoon
showers and a 40–80 percent chance of rain each day. The strongest
showers are expected from Saturday into Monday due to
precipitable water values ranging between 1.9 and 2.3 inches, well
above climatological normals. From Saturday into Sunday, the
southerly wind flow will push showers across the interior,
southern coastal areas, and northern sections. From Monday through
the rest of the workweek, winds could vary from south to west
depending on the final trajectory of Melissa. A more concise
forecast with low uncertainty is expected in the upcoming days as
model guidance begins to converge on a similar solution. &&

.AVIATION...
(06Z TAFS)
Issued at 412 AM AST Wed Oct 22 2025

SHRA/TSRA en route fm the Anegada Passage will cause -RA/VCTS
through the morning hours across the USVI and eastern PR terminals.
Meanwhile, outer rainbands from TS Melissa over the central
Caribbean Sea will continue to bring SHRA/TSRA across the Caribbean
waters and Mona Passage. This can lead to gusty winds around 30 kt
along the southern coast of PR, and tempo MVFR conds at times at
TJPS through the fcst period. Also, early afternoon SHRA/TSRA
expected to develop in and around TJSJ/TJBQ, which can lead to tempo
MVFR conds thru 22/20z. ESE winds at 12-16 kt with gusts up to 26 kt
and higher near SHRA/TSRA.

&&

.MARINE...
Issued at 412 AM AST Wed Oct 22 2025

A fading northerly swell will continue to result in seas up to 7
feet along the offshore Atlantic waters, and the local passages
today were small craft advisories, remaining in effect until 6 PM
AST today. At the surface, the islands will be mostly under a
moderate to locally fresh easterly wind flow today, resulting in
some areas with choppy seas during the day. Cloud coverage with
showers and thunderstorms from Tropical Storm Melissa will
continue to result in some localized hazardous marine conditions
across the Caribbean waters and the Mona Passage.

The marine forecast for the upcoming days remains highly
uncertain, mostly due to the final trajectory of Tropical Storm
Melissa.


&&

.BEACH FORECAST...
Issued at 412 AM AST Wed Oct 22 2025

Hazardous coastal conditions will persist today along the northern
and northeastern exposed beaches, including Culebra and St.
Thomas, due to large breaking waves up to 8 feet. These conditions
will maintain a life-threatening rip current risk for beachgoers.
Therefore, the High Rip Current Risk continues through 6 PM AST
for the aforementioned coastal areas. Beachgoers are urged to
remain out of these waters during the day. An improvement in
coastal conditions is forecast from Thursday into Friday; however,
coastal conditions can deteriorate again for the upcoming weekend.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
526 AM AST Thu Oct 23 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...

* Today, shower and thunderstorm activity is expected to increase
lightning and flooding threat across the region, mainly over
southern and eastern portions of Puerto Rico.

* Occasional periods of showers and thunderstorms will continue
across the U.S. Virgin Islands today through the weekend, with
gusty winds and ponding of water over urban and poorly drained
areas.

* High uncertainty remains in the long-term forecast due high
variability between global model solutions regarding Tropical
Storm Melissa's trajectory.


&&

.SHORT TERM...Today through Saturday...
Issued at 433 AM AST Thu Oct 23 2025

Cloudy skies were observed once again across the islands during the
morning hours. Thunderstorms developed mainly over the Caribbean and
the Mona Passage from outer rainbands from distant TS Melissa over
the central Caribbean Sea. Light to moderate rainfall associated to
this was noted across most of southern and western Puerto Rico.
Meanwhile, passing showers moved at times over portions of the U.S.
Virgin Islands, and brief heavy showers affected portions of the
eastern half of PR. The Doppler radar estimated up to 1.50 inches of
rain in Rio Grande, Patillas, and Maunabo. Minimum temperatures
ranged from the upper-70s to low 80s across the lower elevations of
the islands, and from the mid-60s to mid-70s across the higher
elevations of Puerto Rico. The wind was from the east to southeast
at 10 to 15 mph with gusts up to 28 mph.

There is no significant change on the short-term forecast as outer
rainbands from TS Melissa continue to bring higher moisture content
from the Caribbean waters, and moderate to locally fresh east to
southeast trades bring additional moisture from the tropical
Atlantic. The general rainfall forecast over the next three days
remains the same, with total accumulations of 2 to 4 inches across
the region. However, as Melissa meanders over the central Caribbean
Sea through the weekend, any small variations in its structure and
forecast track could lead to higher amounts, mainly over the
southern and eastern half of PR. Across the USVI, an advective
weather pattern with fast moving showers is expected to prevail
through the period. However, isolated thunderstorms developing over
the local waters could still bring periods of brief heavy downpours.

The main weather hazards are localized urban and small stream
flooding, as well as strong gusty winds across the regional water,
and along coastal counties of eastern and southern PR. As cloudy
skies are expected through most of the period, the heat threat will
remain low.

&&

.LONG TERM...Sunday through Thursday...
Issued at 433 AM AST Thu Oct 23 2025

Uncertainty remains high in the long-term forecast, as the
trajectory and intensity of Tropical Storm Melissa will influence
the weather pattern across the CWA. From the latest NHC bulletin,
Melissa is expected to become a major Hurricane by early Monday,
just south of Jamaica. According to the deterministic guidance of
global models, Melissa will likely turn northeast in the long-term;
however, there is a high spread between model solutions. The
nearest solutions to our CWA are shown by the GFS, positioning
Melissa over the Hispaniola and moving NW of PR and the USVI by
late Monday night into Tuesday. Nevertheless, other model
solutions such as the ECMWF and Google DeepMind, suggest that the
system should move over Jamaica and Cuba, far away of the CWA.
Although there’s high variability between global solutions, in
terms of precipitation, both deterministic guidance of the GFS and
ECMWF show that there’s a medium (between 40 - 60%) chance that
Precipitable Water (PWAT) should remain near to above
climatological normals (2.0 - 2.2 inches, with a low chance of
reaching 2.4 inches) during the forecast period. Nevertheless,
there’s high variability between ensemble members by the end of
the long-term forecast. Therefore, under a SE-S wind pattern, the
most likely scenario is for shower and thunderstorm activity
across the regional waters into windward sections of the islands
each day, with typical afternoon convection over the mountain
ranges of Puerto Rico. Periods of heavy rainfall could lead to
ponding of water over roadways, urban, and poorly drained areas,
increasing the flooding potential over the aforementioned areas.
Residents and visitors are urged to continue to monitor the
development of this system and bulletins from the NHC at
hurricanes.gov.

&&

.AVIATION...
(06Z TAFS)
Issued at 433 AM AST Thu Oct 23 2025

Outer rainbands from TS Melissa will continue to bring SHRA/TSRA
across the Caribbean waters and the Mona Passage during the next few
days. Brief MVFR conds are expected at times across TJPS through the
period, with possible +SHRA later in the afternoon/evening hours
across the rest of the PR terminals. For the USVI terminals, mostly -
RA/VCSH expected. ESE winds up to 27 kt blo FL050.

&&

.MARINE...
Issued at 433 AM AST Thu Oct 23 2025

The interaction between Tropical Storm Melissa and a surface high
pressure to the northeast will promote moderate to locally fresh
easterly winds today, becoming moderate by Friday. Showers and
thunderstorms associated with distant Tropical Storm Melissa, will
continue to result in localized hazardous marine conditions at times.
Mariners are urged to stay protected across these waters.

&&

.BEACH FORECAST...
Issued at 433 AM AST Thu Oct 23 2025

Beach conditions area gradually improving as the northerly swell
continues to fade. Nevertheless, moderate to locally fresh winds
will promote a moderate risk of rip currents across most beaches
of Puerto Rico and the U.S. Virgin Islands for the next days.
Beachgoers must exercise caution, as life-threatening rip currents
are possible in the surf zone. Additionally, showers and
thunderstorms associated to distant Tropical Storm Melissa will
increase lightning threat across the coastal areas. Beachgoers are
urged to stay weather alert.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
503 AM AST Fri Oct 24 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...

* Showers and thunderstorms will increase the flooding and
lightning risk today, mainly over portions of southern and
eastern Puerto Rico.

* Thunderstorm development is expected through the weekend across
the local waters of the islands, which may move over the USVI at
times.

* The moderate risk of rip currents continues for most beaches of
Puerto Rico and the U.S. Virgin Islands, persisting through the
weekend.

&&

.SHORT TERM...
(Today through Sunday)
Issued at 417 AM AST Fri Oct 24 2025

Mostly cloudy skies were observed across Puerto Rico and the U.S.
Virgin Islands overnight. Strong thunderstorms were noted mainly
across the offshore and coastal waters of Puerto Rico, and Mona
Passage. The Doppler radar estimated between 0.25 and 1.25 inches of
rain along the southern to eastern portions of Puerto Rico. Across
the USVI, little to no rainfall was detected overnight. Minimum
temperatures ranged from the upper-70s to low 80s across the lower
elevations of the islands, and from the upper-60s to mid-70s across
the higher elevations of Puerto Rico. The wind was from the
southeast at 10 to 15 mph with gusts up to 25 mph.

A showery pattern will continue during the next few days as pooling
of tropical moisture persists across the Caribbean under the
influence of distant Tropical Storm Melissa, located over the
central Caribbean Sea. The overall precipitable water content is
expected to remain at or above 2.00 inches through the short-term
period. Hi-res model guidance, from the NBM and ECMWF suggest that
today will be another rainy day/night along southern PR, including
portions of the Cordillera Central, with rainfall totals between 1
and 3 inches, and isolated higher amounts possible along south-
central PR. Taking into consideration the previous days rainfall
across these areas with already saturated soils, any brief period of
heavy rainfall could trigger quick flooding and rapid river rises,
as well as minor landslides in areas of steep terrain. The rainfall
pattern should continue over the same areas on Saturday, with
somewhat lesser amounts than today, regardless, the flood threat
will continue elevated across the eastern and southern half of PR.
On Sunday, a transition into a more seasonable weather pattern is
expected, with thunderstorms developing in the afternoon over the
interior and western PR. However, possible lingering cloud cover may
delay the onset of afternoon convection.

&&

.LONG TERM...
(Monday through Friday)
Issued at 417 AM AST Fri Oct 24 2025

No major changes were introduced to the long-term forecast, as
uncertainty remains high for the next workweek due to Tropical Storm
Melissa. From the latest National Hurricane Center bulletin, Melissa
continues as a tropical storm and is expected to become a major
hurricane by early next week. Most global solutions keep suggesting
that Melissa should approach Jamaica in the next few days, then
turning northward, crossing Cuba into the Atlantic waters. Compared
to the latest solutions, GFS is slightly tending to a westerly
track, as the latest run suggests Melissa moving across Haiti
instead of the Dominican Republic. Although there’s still
uncertainty in Melissa’s trajectory, as mentioned in the previous
discussion, high moisture content associated with the system is
still expected across the CWA for at least the first part of the
workweek. The latest guidance continues to suggest a medium chance
(40 - 60%) of PWAT values between 2.0 - 2.2 inches, with a lower
chance of reaching 2.4 inches. However, variability spreads from
seasonal to above-climatological values from Tuesday onwards. Hence,
the most likely scenario remains as winds from the SE-S will bring
showers and isolated thunderstorms over windward sections of the
local islands early in the morning, while afternoon convection can
be expected across the mountain ranges of Puerto Rico if cloud
coverage does not persist each day. Rainfall accumulations could
lead to ponding of water over roadways, urban, and poorly drained
areas, leading to urban and small stream flooding over the
aforementioned areas. Additionally, gusty winds and frequent
lightning may persist as well. Weather conditions may improve by
the end of the period as a surface high pressure may approach the
CWA but once again this will depend on Melissa’s trajectory in the
long term forecast.

&&

.AVIATION...
(06Z TAFS)
Issued at 417 AM AST Fri Oct 24 2025

SHRA/TSRA moving from the Caribbean waters will continue to cause
tempo MVFR to brief IFR conds at TJPS through the fcst period. At
TJSJ/TJBQ, mostly -RA/VCTS expected through tonight. MTN tops obscd
and BKN/OVC lyrs btw FL030-FL150 expected. Across the USVI
terminals, mostly VFR conds expected with occasional -SHRA moving
over the terminals. Wind from the SSE up to 15 kt with stronger
gusts near SHRA.

&&

.MARINE...
Issued at 417 AM AST Fri Oct 24 2025

The interaction between Tropical Storm Melissa and a surface high
pressure over the Central Atlantic will promote moderate to locally
fresh southeasterly winds today, becoming moderate from the east
later tonight. Showers and thunderstorms associated with distant
Tropical Storm Melissa will continue across regional waters and
passages, leading to localized hazardous marine conditions at times.
Mariners are urged to stay protected across these waters.


&&

.BEACH FORECAST...
Issued at 417 AM AST Fri Oct 24 2025

Today, most beaches of Puerto Rico and the U.S. Virgin Islands will
continue under a moderate risk of rip currents, expected to last
through the weekend. Beachgoers are urged to pay attention to the
beach conditions as life-threatening rip currents are possible along
the surf zone. Additionally, beachgoers should remain weather alert
due to outer bands of Tropical Storm Melissa producing showers and
thunderstorms across coastal areas, particularly over the southern
and eastern portions of Puerto Rico and the U.S. Virgin Islands. By
the beginning of next week, the rip current risk is likely to
increase, leading to hazardous beach conditions.