ATL: PHILIPPE - Advisories

[cycloneye]

Tropical Storm Philippe Discussion Number 21
NWS National Hurricane Center Miami FL AL172023
1100 AM AST Thu Sep 28 2023

Philippe remains a very disorganized and elongated storm.
Geostationary and microwave satellite images show a low-level
circulation center well to the west of the mid-level center, where
most of the deep convection is currently concentrated. The
estimated center position shown in this advisory is roughly midway
between those features, however confidence is very low on the
storm's position. In fact, it is possible that Philippe no longer
has a well-defined center. The initial intensity is held at 45 kt,
which is near the high end of the satellite intensity estimates.

The initial motion is highly uncertain since the storm is elongated
and confidence in the initial position is very low. The track
forecast is challenging, in part due to Philippe's close proximity
to newly formed Tropical Storm Rina. In the short term, a slow
southwestward motion seems likely as Philippe moves in weak steering
currents between a mid- to upper-level trough to its northeast and
Rina to its east-southeast. By late in the weekend, a mid-level
ridge is anticipated to build over the subtropical central Atlantic,
and that feature should cause Philippe to turn sharply northward
east of the northern Leeward Islands. The NHC track forecast has
been adjusted to the south for the first couple of days, but lies to
the east of the previous forecast at days 4 and 5. This prediction
is closest to the ECMWF model.

The environmental conditions for Philippe no longer seem unfavorable
given its expected to track to the east of the islands and not
within a region of strong shear. Therefore, the NHC intensity
forecast has been adjusted upward and generally shows little change
in strength during the next several days. This prediction still
lies near the low end of the model guidance, however, so future
advisories might show a higher intensity forecast if the guidance
persists.


FORECAST POSITIONS AND MAX WINDS

INIT 28/1500Z 18.6N 54.6W 45 KT 50 MPH
12H 29/0000Z 18.7N 55.1W 45 KT 50 MPH
24H 29/1200Z 18.6N 55.6W 45 KT 50 MPH
36H 30/0000Z 18.4N 56.1W 45 KT 50 MPH
48H 30/1200Z 18.0N 56.7W 45 KT 50 MPH
60H 01/0000Z 17.6N 57.2W 45 KT 50 MPH
72H 01/1200Z 17.3N 57.5W 45 KT 50 MPH
96H 02/1200Z 17.7N 58.2W 45 KT 50 MPH
120H 03/1200Z 20.0N 58.9W 40 KT 45 MPH

$$
Forecaster Cangialosi/A Reinhart

[cycloneye]

Tropical Storm Philippe Discussion Number 22
NWS National Hurricane Center Miami FL AL172023
500 PM AST Thu Sep 28 2023

Philippe remains poorly organized. Visible satellite images
indicate that the circulation is elongated from east to west and
appears to have multiple centers along a trough axis. The center
position listed in the advisory seems to be the main center and
there is some deep convection on its east and southeast sides.
Philippe barely meets the criteria needed for a tropical cyclone as
it has lost some organization today. The initial intensity is
lowered to 40 kt, which is near the high end of the latest satellite
intensity estimates.

The initial motion is highly uncertain since the storm is elongated
and confidence in the initial position remains low. The track
forecast is challenging, in part due to Philippe's close proximity
to Tropical Storm Rina. During the next few days, Philippe will
likely move slowly southwestward as it rotates around Rina
currently to its east. By late in the weekend, however, a sharp
northward turn is expected when a mid-level ridge becomes
established over the central subtropical Atlantic. There remains a
very large east-west spread in the models, and disagreements on
where Philippe makes its northward turn. The GFS is the right-most
model while the ECMWF remains the model farthest west. The NHC
track forecast is little changed from the previous one and remains
closest to the ECMWF model, which has been performing best so far
for this storm.

The observed weakening of the system today appears to be related to
its interaction with Rina and some environmental dry air. Since
these factors are expected to persist, some additional weakening is
forecast during the next day or so, and it is possible that Philippe
dissipates sometime during the next couple of days. However, if the
storm does survive, environmental conditions are expected to become
a little more favorable when Philippe and Rina become more
separated later in the forecast period. There is a huge spread in
the intensity models with HWRF, HMON, and the GFS showing Philippe
becoming a significant hurricane while the HAFS-A and HAFS-B models
show gradual weakening. The NHC intensity forecast is a little
lower than the previous one in the short term, but is otherwise
unchanged and closer to the low end of the model guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 28/2100Z 18.9N 55.1W 40 KT 45 MPH
12H 29/0600Z 18.9N 55.5W 35 KT 40 MPH
24H 29/1800Z 18.7N 55.9W 35 KT 40 MPH
36H 30/0600Z 18.3N 56.2W 40 KT 45 MPH
48H 30/1800Z 17.9N 56.4W 45 KT 50 MPH
60H 01/0600Z 17.5N 57.0W 45 KT 50 MPH
72H 01/1800Z 17.0N 57.6W 45 KT 50 MPH
96H 02/1800Z 18.6N 58.6W 45 KT 50 MPH
120H 03/1800Z 20.6N 59.1W 40 KT 45 MPH

$$
Forecaster Cangialosi

[cycloneye]

Tropical Storm Philippe Discussion Number 23
NWS National Hurricane Center Miami FL AL172023
1100 PM AST Thu Sep 28 2023

There has not been much change in Philippe's organization this
evening with deep convection pulsing around the eastern and
southern portions of the circulation. Satellite imagery and a very
recently arriving ASCAT pass indicate that the circulation is
quite elongated east to west. In fact, the ASCAT data suggests
Philippe likely lacks a well-defined center, but there are some
indications that a center may be trying to re-form farther east.
Subjective Dvorak T-numbers from SAB and TAFB were T2.0 (30 kt) and
T2.5 (35 kt), respectively at 00Z, but the recently arriving ASCAT
data revealed winds of around 35-36 kt. Given the typical
undersampling of that instrument, the initial wind speed is held
at 40 kt.

The scatterometer data suggests that Philippe is located a little
south of the previous estimates, but the storm appears to have moved
little since the previous advisory. The track forecast is still
quite challenging due to the current disorganized structure and the
close proximity of Tropical Storm Rina to Philippe's east. The
dynamical model guidance suggests that the cyclone will move slowly
southwestward as Rina moves to the northeast of Philippe during the
next two to three days. By early next week, the storm is forecast
to begin moving northward between a mid-level ridge over the
east-central Atlantic and a mid- to upper-level trough over the
southwestern Atlantic. There is still significant spread in the
models on where Philippe makes the northward turn, but the guidance
is in slightly better agreement than 24 hours ago. The updated NHC
track is a little to the right of the previous forecast, but it
lies a little west of the latest consensus aids. There continues to
be larger-than-normal uncertainty in the latter portion of the
track forecast.

Westerly shear, dry air, and Philippe's close proximity to Rina
have continued to prevent any increase in organization today.
Those negative environmental factors are expected to linger during
the next day or so, and little overall change in strength is
forecast during that time. Although not explicitly shown in this
forecast or by most of the model guidance, it is possible that
Philippe's circulation becomes increasing elongated and the system
dissipates within the next couple of days. However, most of the
guidance shows Philippe surviving, and then finding a more favorable
environment in which to strengthen early next week. The NHC
intensity forecast has been nudged upward from 72-120 h, but it
remains below much the latest dynamical guidance and the consensus
aids. Until there is a bit more clarity it seems prudent to stay
on the more conservative side of the guidance. As with the track
forecast, there is still significant uncertainty in the long-range
intensity prediction for Philippe.


FORECAST POSITIONS AND MAX WINDS

INIT 29/0300Z 18.3N 55.0W 40 KT 45 MPH
12H 29/1200Z 18.2N 55.2W 40 KT 45 MPH
24H 30/0000Z 17.9N 55.6W 40 KT 45 MPH
36H 30/1200Z 17.6N 55.9W 40 KT 45 MPH
48H 01/0000Z 17.2N 56.2W 45 KT 50 MPH
60H 01/1200Z 17.0N 56.6W 45 KT 50 MPH
72H 02/0000Z 17.0N 57.0W 50 KT 60 MPH
96H 03/0000Z 18.8N 57.6W 50 KT 60 MPH
120H 04/0000Z 21.7N 58.3W 50 KT 60 MPH

$$
Forecaster Brown

[cycloneye]

Tropical Storm Philippe Discussion Number 24
NWS National Hurricane Center Miami FL AL172023
500 AM AST Fri Sep 29 2023

A 0546 UTC GMI microwave pass showed that Philippe continues to
have a broad circulation, with the low-level center located
somewhere near the northwestern edge of a large area of deep
convection. There is a large range in the subjective Dvorak
estimates (30-55 kt), but the various objective numbers from
UW-CIMSS are in closer agreement (35-45 kt). Using a blend of
these values, as well as ASCAT data from last evening, Philippe's
intensity is held at 40 kt.

While there is a bit of uncertainty in the exact location of the
center, the storm does appear to be drifting toward the southwest
(235 degrees) at about 2 kt. Philippe's movement during the next
3-4 days is likely to be dictated by binary interaction with
Tropical Storm Rina to the east. The bulk of the track guidance
indicates that Philippe will dip farther toward the southwest during
the next 48 hours due to Rina's influence, but then turn toward the
northwest and north on days 3 through 5 as a mid-tropospheric high
builds over the central Atlantic. The new NHC track forecast is
not much different from the previous prediction and is close to the
TVCA and HCCA consensus aids. The HAFS regional hurricane models
show little to no interaction between Philippe and Rina during the
next few days. However, with the two storms located only 500 n mi
apart from each other, some degree of interaction is likely, and
therefore the western solutions shown by those models (near or over
the northern Leeward Islands) appear to be outliers at this time.
That said, there continues to be larger-than-normal uncertainty in
Philippe's future track.

A combination of shear, dry air, and Philippe's proximity to Rina
are likely to cause little change in intensity for the next day or
so. However, the global models have trended toward Philippe not
only surviving the next few days, but also deepening in an
environment of increasing upper-level divergence (and still over
very warm waters of 29-30 degrees Celsius). The NHC intensity
forecast has been nudged upward from 36 hours onward, although it
still sits well below most of the intensity models, including the
consensus aids, during the latter part of the forecast period.
Until it becomes more clear how Philippe will evolve over the next
couple of days, the official intensity forecast will remain on the
conservative side, but future adjustments to the forecast are
becoming more likely.


FORECAST POSITIONS AND MAX WINDS

INIT 29/0900Z 18.5N 55.2W 40 KT 45 MPH
12H 29/1800Z 18.3N 55.4W 40 KT 45 MPH
24H 30/0600Z 17.9N 55.7W 40 KT 45 MPH
36H 30/1800Z 17.4N 56.0W 45 KT 50 MPH
48H 01/0600Z 17.1N 56.4W 50 KT 60 MPH
60H 01/1800Z 17.1N 56.8W 50 KT 60 MPH
72H 02/0600Z 17.6N 57.2W 55 KT 65 MPH
96H 03/0600Z 20.0N 57.9W 55 KT 65 MPH
120H 04/0600Z 23.1N 58.1W 55 KT 65 MPH

$$
Forecaster Berg

[cycloneye]

Tropical Storm Philippe Discussion Number 25
NWS National Hurricane Center Miami FL AL172023
1100 AM AST Fri Sep 29 2023

There has been little change in Philippe's satellite appearance this
morning. The storm remains sheared with the low-level center
located near the western edge of the main area of deep convection.
The satellite intensity estimates continue to have a large spread,
ranging from 30 to 55 kt. ASCAT data should be available soon, and
the Air Force Hurricane Hunters are scheduled to investigate
Philippe this afternoon. Both of these datasets will provide a
better assessment of Philippe's intensity and structure.

Philippe has only moved roughly 40 miles over the past 24 hours, and
it has been generally drifting to the southwest during that time.
The slow motion over the past day or so is due to its interaction
with Tropical Storm Rina several hundred miles to its east. Since
these tropical cyclones are expected to continue to interact through
the weekend, Philippe is forecast to crawl southwestward during the
next 2 or 3 days. After that time, Rina is expected to separate
from Philippe as a mid-level ridge builds over the subtropical
central Atlantic. In response, Philippe should turn sharply
northward early next week. Although there remains a fair amount of
spread in the models, they are in considerably better agreement
today compared to the past couple of days. Overall, little change
was made to the previous track forecast, and it continues to lie
close to the various consensus models.

Although Philippe is still being affected by shear, the environment
over the next several days appears to become less hostile. Light
to moderate wind shear, increasing mid-level humidities around the
storm, and very warm SSTs should allow Philippe to gradually
strengthen. The NHC intensity forecast has been nudged upward
again this cycle, but still lies on the lower end of the model
guidance. Additional upward revisions seem likely if the
guidance persists.


FORECAST POSITIONS AND MAX WINDS

INIT 29/1500Z 18.3N 55.3W 40 KT 45 MPH
12H 30/0000Z 18.1N 55.4W 40 KT 45 MPH
24H 30/1200Z 17.8N 55.7W 45 KT 50 MPH
36H 01/0000Z 17.4N 56.1W 50 KT 60 MPH
48H 01/1200Z 17.3N 56.5W 55 KT 65 MPH
60H 02/0000Z 17.5N 56.9W 55 KT 65 MPH
72H 02/1200Z 18.4N 57.5W 60 KT 70 MPH
96H 03/1200Z 21.5N 58.0W 60 KT 70 MPH
120H 04/1200Z 26.1N 57.4W 60 KT 70 MPH

$$
Forecaster Cangialosi

[cycloneye]

Tropical Storm Philippe Discussion Number 26
NWS National Hurricane Center Miami FL AL172023
500 PM AST Fri Sep 29 2023

Satellite imagery shows the center of Philippe has become exposed
again due to 15-20 kt of mid-level westerly shear. Deep convection
is generally confined to the southeast portion, with a growing band
to the south of the center. The Air Force Hurricane Hunters
investigated Philippe this afternoon and found the minimum pressure
to be 1002 mb and winds to support an intensity of 45 kt. Based on
the aircraft and ASCAT data, tropical-storm-force winds extend well
east and southeast of the center.

Philippe is moving a little faster this afternoon, but still
relatively slowly as it continues in a general southwest direction.
The current track is due to its interaction with Tropical Storm Rina
several hundred miles to its east. Since these tropical cyclones
are expected to continue to interact through the weekend, Philippe
is forecast to crawl southwestward through Sunday. After that time,
Rina is expected to separate from Philippe as a mid-level ridge
builds over the subtropical central Atlantic. In response, Philippe
should turn sharply northward early next week. Recent guidance has
shown an overall shift to the west, with the 12Z ECMWF model about
60 n mi west of its previous run. The NHC track forecast has also
been nudged to the west toward the various consensus models.

Although Philippe is still being affected by shear, the environment
over the next couple of days appears to become less hostile.
Moderate wind shear, upper-level diffluence, increasing mid-level
humidities around the storm, and very warm SSTs should allow
Philippe to gradually strengthen through the weekend. Beyond that
time, the intensity forecast becomes more dependent on the future
track. If Philippe tracks along the western side of the guidance, it
will likely weaken due to stronger wind shear. Whereas, if the
system tracks east of the NHC track, it could strengthen more than
predicted due to more favorable environmental factors. The NHC
intensity forecast is a little higher than the previous cycle in the
short term, but is still on the low end of the guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 29/2100Z 18.0N 55.9W 45 KT 50 MPH
12H 30/0600Z 17.6N 56.2W 45 KT 50 MPH
24H 30/1800Z 17.3N 56.5W 50 KT 60 MPH
36H 01/0600Z 17.2N 57.0W 55 KT 65 MPH
48H 01/1800Z 17.6N 57.4W 60 KT 70 MPH
60H 02/0600Z 18.3N 58.0W 60 KT 70 MPH
72H 02/1800Z 19.5N 58.3W 60 KT 70 MPH
96H 03/1800Z 22.9N 58.7W 60 KT 70 MPH
120H 04/1800Z 26.9N 57.7W 60 KT 70 MPH

$$
Forecaster Cangialosi

[cycloneye]

Tropical Storm Philippe Discussion Number 27
NWS National Hurricane Center Miami FL AL172023
1100 PM AST Fri Sep 29 2023

Deep convection continues to pulse over the southeastern portion of
Philippe's circulation this evening. The center is located near
the northwestern edge of the deep convection due to moderate
westerly shear. The intensity is held at 45 kt, and is based on
the earlier reconnaissance aircraft data and a T3.0 (45 kt)
subjective Dvorak classification from TAFB. Another Air Force
Reserve reconnaissance mission is scheduled overnight, and this
mission should provide a full assessment of Philippe's structure
and intensity.

The earlier aircraft center fixes and more recent satellite
position estimates indicate that Philippe is moving slowly
southwestward. This motion is being influenced by Philippe's
interaction with Tropical Storm Rina located to Philippe's
east-northeast. As the two tropical cyclone's continue to
interact, Philippe is expected to move slowly west-southwestward
to westward during the next 24 to 36 hours. After that time, the
distance between the tropical cyclones should increase, and
Philippe is forecast to turn northwestward when a mid-level ridge
builds over the central Atlantic. After 72 hours, Philippe is
expected to turn northward between the aforementioned ridge and a
mid- to upper-level trough over the southwestern Atlantic.
Although the models are in general agreement on this scenario,
there is significant spread on the longitude of the northward turn,
and on how fast Philippe moves later in the period. The updated
NHC track forecast is near the various consensus aids, and very
close to the previous advisory.

The moderate shear that has been affecting Philippe the past few
days could lessen during the next day or two. This should allow
for some gradual strengthening over the weekend. After that time,
there is a bifurcation in the intensity guidance with the
GFS-based SHIPS model, the HMON, the HWRF, and even the GFS showing
a more favorable upper-air environment and more significant
deepening with a track farther east. Meanwhile, the ECMWF-based
SHIPS guidance, and the HAFS-A and HAFS-B which show a more westward
track keeps stronger southwesterly vertical wind shear over the
storm and therefore less strengthening. The NHC intensity foreast
is near the middle of these two scenarios, but is a bit more
conservative than the lastest intensity consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0300Z 17.6N 55.8W 45 KT 50 MPH
12H 30/1200Z 17.3N 56.0W 45 KT 50 MPH
24H 01/0000Z 17.2N 56.4W 50 KT 60 MPH
36H 01/1200Z 17.3N 56.9W 55 KT 65 MPH
48H 02/0000Z 17.8N 57.5W 60 KT 70 MPH
60H 02/1200Z 18.7N 58.2W 60 KT 70 MPH
72H 03/0000Z 20.2N 58.7W 60 KT 70 MPH
96H 04/0000Z 23.4N 58.9W 60 KT 70 MPH
120H 05/0000Z 27.3N 57.5W 60 KT 70 MPH

$$
Forecaster Brown

[cycloneye]

Tropical Storm Philippe Discussion Number 28
NWS National Hurricane Center Miami FL AL172023
500 AM AST Sat Sep 30 2023

An Air Force Reserve Hurricane Hunter crew investigated Philippe a
few hours ago and found that the minimum pressure had fallen to 999
mb, however the maximum winds do not appear to have increased. The
maximum flight-level wind was 46 kt at 700 mb, and SFMR readings
outside of deep convection were as high as 45 kt (SFMR measurements
higher than 50 kt appeared questionable due to coincident heavy
rain). The low-level center remains located on the northwestern
edge of the deep convection due to continued shear.

The reconnaissance fixes showed that Philippe has been moving toward
the south-southwest (200 degrees) at about 4 kt. The storm has
moved a little farther south than expected, possibly due to a more
pronounced binary interaction with Tropical Storm Rina about 450 n
mi to its east-northeast. As the interaction continues, Philippe is
forecast to move slowly toward the west and then northwest during
the next few days. However, there is still quite a bit of model
spread in how far west Philippe will get before it turns, and the
ECMWF and HAFS-B models in particularly bring the storm very close
to the northern Leeward Islands in about 48 hours. The NHC track
forecast has been shifted west of the previous prediction and lies
just to the west of the TVCA consensus aid. It is noteworthy that
several models and ensemble members still lie west of the new
forecast, and it's possible that additional adjustments may be
required in future forecast cycles. All models show Philippe
accelerating toward the north and north-northeast by days 4 and 5,
steered by the flow between a mid-level high over the central
Atlantic and a deep-layer trough over the western Atlantic.

The intensity forecast remains tricky and is complicated by
competing positive and negative environmental factors. On one hand,
moderate-to-strong northwesterly shear is likely to continue at
least for the next 48 hours. However, the magnitude of the shear
will depend on Philippe's exact location, and it could also be
offset by a more diffluent upper-level environment. Since the storm
has already been overachieving in the sheared environment, the NHC
intensity forecast shows gradual strengthening during the next few
days, and is near or just below the IVCN and HCCA consensus aids
through 60 hours. The atmosphere could become more favorable for
strengthening after that time, and the NHC forecast now shows
Philippe reaching hurricane intensity while it recurves toward the
subtropical Atlantic. It's worth noting that this new forecast is
still on the conservative side, and that many of the intensity
models and consensus aids are at least 20 kt higher on days 4 and 5.
Only the ECMWF and its SHIPS and LGEM derivatives remain on the
weaker end of the scale and don't bring Philippe to hurricane
strength.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0900Z 17.1N 55.9W 45 KT 50 MPH
12H 30/1800Z 16.9N 56.2W 50 KT 60 MPH
24H 01/0600Z 16.9N 56.7W 50 KT 60 MPH
36H 01/1800Z 17.3N 57.5W 55 KT 65 MPH
48H 02/0600Z 18.0N 58.3W 60 KT 70 MPH
60H 02/1800Z 19.2N 59.0W 65 KT 75 MPH
72H 03/0600Z 20.7N 59.5W 65 KT 75 MPH
96H 04/0600Z 24.1N 59.3W 65 KT 75 MPH
120H 05/0600Z 28.1N 56.6W 65 KT 75 MPH

$$
Forecaster Berg

[cycloneye]

Tropical Storm Philippe Discussion Number 29
NWS National Hurricane Center Miami FL AL172023
1100 AM AST Sat Sep 30 2023

The satellite presentation of Philippe has not changed much this
morning. The partially exposed low-level circulation lies on the
western edge of a deep convective mass, as northwesterly shear
continues to affect the storm's stucture. Recent UW-CIMSS objective
estimates and subjective Dvorak classifications from TAFB and SAB
have generally held steady, and so the initial intensity remains at
45 kt for this advisory. The Air Force Reserve Hurricane Hunters
are scheduled to investigate the system later today.

The estimated initial motion of Philippe is southwestward (210/4
kt). Philippe is not expected to move much during the next 12-24 h,
although there is uncertainty even in the near term related to the
extent of the interaction between Philippe and Tropical Storm Rina
to its northeast. Most of the models show a slow and generally
westward motion during the next day or so, which is reflected in
the NHC forecast. Then, model spread increases regarding the timing
of Philippe's turn toward the northwest and north early next week.
Stronger model solutions (GFS, HAFS-A) depict an earlier turn along
the eastern side of the guidance envelope, while weaker models
(ECMWF, UKMET) show the storm making it west of 60W before turning.
Given the greater-than-normal model spread, the NHC forecast remains
near the TVCA and HCCA aids for this portion of the forecast, with
a slight westward adjustment from the previous prediction. By days
4-5, Philippe is forecast to move faster toward the north and
northeast between a mid-level ridge over the central Atlantic and a
deep-layer trough over the western Atlantic.

Given the sheared structure of Philippe, only minor intensity
fluctuations are expected during the next 12-24 h. Thereafter, the
shear is generally forecast to decrease on Monday and Tuesday,
although the magnitude remains at least somewhat dependent on how
far west Philippe tracks. Based on our latest track forecast, it is
assumed that the shear will relax enough to be conducive for some
strengthening over the 29-29.5C SSTs, and this prediction shows
Philippe becoming a hurricane by 60 h. Overall, the environment
appears reasonably favorable for continued strengthening through
days 4-5 as the cyclone moves into the subtropical Atlantic. The
updated intensity forecast has been raised during this period to
show additional strengthening, although it still lies below the
IVCN and HCCA aids, so further adjustments could be necessary.


FORECAST POSITIONS AND MAX WINDS

INIT 30/1500Z 16.9N 56.3W 45 KT 50 MPH
12H 01/0000Z 16.8N 56.6W 50 KT 60 MPH
24H 01/1200Z 17.0N 57.2W 50 KT 60 MPH
36H 02/0000Z 17.6N 58.0W 55 KT 65 MPH
48H 02/1200Z 18.5N 58.9W 60 KT 70 MPH
60H 03/0000Z 19.7N 59.6W 65 KT 75 MPH
72H 03/1200Z 21.0N 59.9W 70 KT 80 MPH
96H 04/1200Z 24.9N 59.3W 75 KT 85 MPH
120H 05/1200Z 28.5N 57.0W 75 KT 85 MPH

$$
Forecaster Reinhart

[cycloneye]

Tropical Storm Philippe Discussion Number 30
NWS National Hurricane Center Miami FL AL172023
500 PM AST Sat Sep 30 2023

Philippe remains a sheared tropical cyclone. Its low-level center
has become increasingly separated from the deep convection today.
Visible satellite images and and fixes from the Air Force Hurricane
Hunters indicate the center is farther south and slightly east of
our previous estimates. In terms of Philippe's current intensity,
there were mixed signals in the aircraft data. The peak 850-mb
flight-level winds were only 49 kt, and a center dropsonde indicated
no change of the minimum pressure (999 mb) since the previous
flight. On the other hand, the SFMR retrievals showed winds of 45-50
kt outside of convection that were visually supported by the flight
crew, but a coincident dropsonde reported much lower near-surface
wind speeds. Given the conflicting data and less impressive
satellite presentation, the initial intensity is held at 45 kt.

The tropical storm has continued to move southwestward today, with
an initial motion of 215/4 kt. In the near term, the models suggest
Philippe will not move very much and could drift erratically through
early Sunday while Tropical Storm Rina passes to its north. Then,
there is general agreement that the storm will turn toward the
west-northwest and northwest around the western extent of a low- to
mid-level ridge over the central Atlantic. While there is still a
large spread in the track guidance during the 24-72 h time frame, it
is noteworthy that the 12z ECMWF has trended eastward this cycle and
shows Philippe passing farther east of the northern Leeward Islands.
The latest NHC track forecast is slightly farther south and west
early in the forecast due to the center relocation. However, the
updated prediction ends up near or slightly east of the previous
forecast at 36-72 h, in best agreement with the TVCA simple
consensus. By days 4-5, Philippe is forecast to accelerate northward
and northeastward between a central Atlantic ridge and a deep-layer
trough over the western Atlantic.

Only modest strengthening is forecast during the next 24-36 h while
Philippe contends with moderate to strong northwesterly shear. The
upper-level winds are forecast to become more conducive for
intensification in a couple of days or so, which should allow the
cyclone to become more vertically aligned and establish an inner
core. Thus, more strengthening is forecast at days 2-4 while
Philippe moves over the very warm SSTs of the central Atlantic,
which is supported by almost all of the intensity guidance. The NHC
forecast calls for Philippe to become a hurricane by 60 h with
continued strengthening thereafter. The peak intensity was raised to
bring the NHC forecast slightly closer to the latest HCCA and IVCN
aids at days 4-5, but it is noted that the regional hurricane models
are even stronger than the current NHC forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 30/2100Z 16.3N 56.5W 45 KT 50 MPH
12H 01/0600Z 16.2N 56.7W 50 KT 60 MPH
24H 01/1800Z 16.6N 57.4W 55 KT 65 MPH
36H 02/0600Z 17.4N 58.1W 55 KT 65 MPH
48H 02/1800Z 18.5N 58.9W 60 KT 70 MPH
60H 03/0600Z 19.9N 59.5W 65 KT 75 MPH
72H 03/1800Z 21.6N 59.7W 70 KT 80 MPH
96H 04/1800Z 25.7N 59.0W 80 KT 90 MPH
120H 05/1800Z 29.5N 56.0W 80 KT 90 MPH

$$
Forecaster Reinhart

[cycloneye]

Tropical Storm Philippe Discussion Number 31
NWS National Hurricane Center Miami FL AL172023
1100 PM AST Sat Sep 30 2023

Philippe's convective cloud pattern remains rather ragged-looking,
but there are very cold cloud tops of -80 deg C or colder over the
southeastern part of the circulation. The center of circulation is
estimated to be near the northwestern edge of the main area of deep
convection. There is little evidence of banding features at this
time. The current intensity estimate is kept at 45 kt in agreement
with the latest Dvorak classification from TAFB although objective
satellite estimates are somewhat lower. A recent scatterometer
pass showed slightly higher winds over the southeastern quadrant
but these are believed to be rain-inflated. Another Hurricane
Hunter aircraft is scheduled to investigate Philippe tomorrow
morning to check on the intensity of the storm.

The motion is somewhat uncertain since the center is not easy to
locate in nighttime satellite imagery. However it appears that
Philippe is moving more to the right and the initial motion
estimate is now 230/4 kt. Steering currents are expected to remain
ill-defined for the next day or two, but a weak mid-level high to
the northeast of the system should cause Philippe to turn
northwestward on Sunday. In about 3 days, a turn to the north is
expected as the cyclone moves along the western side of the high.
Late in the forecast period, the system should turn toward the
north-northeast on the southeast side of a mid-tropospheric trough
over the western Atlantic. The latest track guidance for the next
48 hours or so, in particular the new GFS, has shifted westward
from the previous cycle. This has resulted in a westward shift of
the model consensus and necessitated a westward shift in the NHC
track as well, which is now closer to the northern Leeward Islands.
It should be noted that the model guidance continues to show very
little outward extent of tropical-storm-force winds over the
western semicircle of Philippe through 48 hours, and this forecast
still does not necessitate the issuance of tropical storm watches
for those islands. However, interests there should continue to
monitor the progress of Philippe.

Based on the global model forecasts, the system is likely to
continue experiencing significant vertical wind shear for the next
day or two. Therefore only a slow increase in intensity is
forecast during the next couple of days. Later in the forecast
period, vertical shear is expected to lessen somewhat which should
allow the system to strengthen into a hurricane, as suggested by
the regional hurricane model, HAFS-A. However, the official
intensity forecast is now above most of the model guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0300Z 16.1N 57.0W 45 KT 50 MPH
12H 01/1200Z 16.5N 57.7W 45 KT 50 MPH
24H 02/0000Z 17.1N 58.6W 50 KT 60 MPH
36H 02/1200Z 17.8N 59.4W 55 KT 65 MPH
48H 03/0000Z 18.6N 60.3W 60 KT 70 MPH
60H 03/1200Z 19.6N 61.0W 60 KT 70 MPH
72H 04/0000Z 21.1N 61.2W 65 KT 75 MPH
96H 05/0000Z 24.8N 61.1W 75 KT 85 MPH
120H 06/0000Z 28.5N 59.2W 80 KT 90 MPH

$$
Forecaster Pasch

[cycloneye]

Tropical Storm Philippe Discussion Number 32
NWS National Hurricane Center Miami FL AL172023
500 AM AST Sun Oct 01 2023

The center of Philippe has become exposed to the northwest of the
large convective mass seen infrared satellite imagery. A very
timely AMSR2 microwave overpass helped to pinpoint the center
location around 0600 UTC, and since that time the center has become
more apparent in the geostationary satellite imagery. Philippe is
still producing a large area of convection with clouds tops colder
than -80 deg C to the southeast of its center. The latest Dvorak
satellite estimates range from 45 kt from SAB to 55 kt from TAFB.
The initial intensity is held at 45 kt in agreement with the
earlier scatterometer data. An Air Force Reserve Hurricane Hunter
aircraft is scheduled to investigate Philippe again this morning.

Philippe is moving a little faster toward the west overnight. A
weak mid-level ridge to the northeast of the cyclone should begin
to steer Philippe west-northwestward to northwestward by later
today, and that motion is expected to continue into Monday. The
track guidance has once more shifted westward during the first
couple of days, which has again necessitated a westward shift in
the NHC track forecast during that time. The new track forecast is
a little closer to the northern Leeward Islands. It should be
noted that the model guidance continues to show very little outward
extent of tropical-storm-force winds over the western semicircle of
Philippe through 48 hours, however given the typical track forecast
uncertainty tropical storm watches or warnings could be required
for a portion of the northern Leeward Islands later today. After
48 hours, Philippe is expected to turn northward as it moves around
the western side of the ridge. Later in the forecast period, a
mid-tropospheric trough over the western Atlantic should cause
Philippe to turn north-northeastward.

The global models and the SHIPS intensity guidance indicate that
the west-northwesterly vertical shear over Philippe will remain
strong during the next couple of days. Therefore, little change in
strength is expected during that time. Later in the forecast
period, the vertical shear could lessen somewhat allowing Philippe
to strengthen. The intensity models are generally lower this
cycle, and the NHC forecast has been adjusted downward but it
remains at the upper end of guidance.

KEY MESSAGES:

1. Philippe is forecast to pass near or just northeast of the
northern Leeward Islands Monday and Monday night. Interests
there should continue to monitor the progress of this system as
tropical storm watches or warnings could be required for a portion
of that area later today.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0900Z 16.4N 58.2W 45 KT 50 MPH
12H 01/1800Z 16.9N 58.9W 45 KT 50 MPH
24H 02/0600Z 17.6N 59.8W 45 KT 50 MPH
36H 02/1800Z 18.4N 60.8W 45 KT 50 MPH
48H 03/0600Z 19.2N 61.3W 50 KT 60 MPH
60H 03/1800Z 20.4N 61.8W 50 KT 60 MPH
72H 04/0600Z 21.9N 62.0W 55 KT 65 MPH
96H 05/0600Z 25.5N 61.6W 65 KT 75 MPH
120H 06/0600Z 28.9N 59.8W 70 KT 80 MPH

$$
Forecaster Brown

[cycloneye]

Tropical Storm Philippe Discussion Number 33
NWS National Hurricane Center Miami FL AL172023
1100 AM AST Sun Oct 01 2023

Philippe is not a well organized tropical cyclone at this time,
with any of the associated deep convection about a degree southeast
of the center due to persistent northwesterly shear. Satellite
intensity estimates are about the same as before, so the initial
wind speed is held 45 kt on this advisory. A scatterometer pass
just received also supports that value.

The storm appears to be moving westward this morning, judging from
fixes on the visible imagery. Weak mid-level ridging is forecast to
build east of the tropical cyclone soon, which probably will steer
Philippe toward the west-northwest or northwest later today, and
eventually northward as it moves into the subtropics. The
short-term forecast steering is extremely challenging due to the
changing depth of associated deep convection, the cyclone vortex
strength, and the related steering flow. Regardless, it is clear
that the risk to the northern Leeward Islands has increased, and the
new forecast is adjusted west of the previous one, which
necessitated the tropical storm watches. Further westward shifts
and other watches/warnings are possible later today since Philippe
has not been a well-behaved system in such a complex steering flow.

Strong shear should continue near Philippe for the next day or so,
leading to little overall change in strength during that time. A
gradual lessening of the shear is anticipated by Tuesday, but model
guidance is in poor agreement on whether the shear will be low
enough for significant strengthening, like many of the regional
hurricane models suggest, or if Philippe stays sheared like the
ECMWF solution. For now, the forecast takes the middle of the road
in the guidance, leading to little change from the last NHC
prediction.


KEY MESSAGES:

1. Tropical storm conditions are possible across portions of the
northern Leeward Islands Monday and Monday night while Philippe
passes near or just northeast of the area, and a Tropical Storm
Watch has been issued for Antigua and Barbuda. Interests elsewhere
in the northern Leeward Islands should continue to monitor this
system as additional watches or warnings could be required later
today or tonight.

2. Heavy rainfall from Philippe could produce isolated to scattered
flash flooding, particularly across Barbuda and Antigua, through
Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT 01/1500Z 16.1N 58.7W 45 KT 50 MPH
12H 02/0000Z 16.5N 59.5W 45 KT 50 MPH
24H 02/1200Z 17.1N 60.5W 45 KT 50 MPH
36H 03/0000Z 17.9N 61.3W 50 KT 60 MPH
48H 03/1200Z 19.0N 62.1W 50 KT 60 MPH
60H 04/0000Z 20.3N 62.3W 50 KT 60 MPH
72H 04/1200Z 22.0N 62.3W 55 KT 65 MPH
96H 05/1200Z 25.8N 61.8W 65 KT 75 MPH
120H 06/1200Z 29.5N 59.0W 75 KT 85 MPH

$$
Forecaster Blake

[cycloneye]

BULLETIN
Tropical Storm Philippe Intermediate Advisory Number 33A
NWS National Hurricane Center Miami FL AL172023
200 PM AST Sun Oct 01 2023

...PHILIPPE MOVING ERRATICALLY WEST-NORTHWESTWARD...
...HEAVY RAIN AND FLASH FLOOD THREAT STARTING OVERNIGHT FOR THE
LEEWARD ISLANDS...


SUMMARY OF 200 PM AST...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...16.2N 58.8W
ABOUT 170 MI...275 KM E OF GUADELOUPE
ABOUT 220 MI...355 KM ESE OF BARBUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES

[cycloneye]

BULLETIN
Tropical Storm Philippe Advisory Number 34
NWS National Hurricane Center Miami FL AL172023
500 PM AST Sun Oct 01 2023

...HEAVY RAIN AND FLASH FLOOD THREAT BEGINNING OVERNIGHT FOR THE
LEEWARD ISLANDS DUE TO PHILIPPE...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...16.4N 59.0W
ABOUT 160 MI...255 KM E OF GUADELOUPE
ABOUT 205 MI...325 KM ESE OF BARBUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Antigua, Barbuda

Interests elsewhere in the northern Leeward Islands should monitor
the progress of this system. Additional tropical storm watches
could be required tonight or on Monday.





Tropical Storm Philippe Discussion Number 34
NWS National Hurricane Center Miami FL AL172023
500 PM AST Sun Oct 01 2023

The structure of Philippe has not changed much since this morning. A
large area of deep convection remains in the southeastern quadrant
of the cyclone, with a small burst near the center. The initial
wind speed is held at 45 kt, per the latest satellite
classifications, and an Air Force Reserve Hurricane Hunter aircraft
is scheduled to be inside the storm tonight.

The southward progress of Philippe has thankfully stopped today,
and recent fixes show it moving between west-northwest and
northwest at about 6 kt. A building ridge well to the northeast
should steer the storm generally northwestward tonight and Monday,
with a turn to the north forecast on Tuesday while the system moves
around the western periphery of the ridge. Eventually a faster
north-northeastward motion is anticipated at long range as the storm
enters the mid-latitudes. While the track forecast has been
adjusted a bit to the east, this should not be interpreted as the
end of any threat to the Leeward Islands with still some models
near those islands. Notably, a very strong rain band on the
southern side of Philippe will be very close to moving over the
northern Leeward Islands, and it could turn out that rainfall and
flooding would be the main hazard of the storm.

There's been no change to the intensity forecast reasoning from the
last cycle, with strong shear near Philippe expected to limit
intensification during the next couple of days. There remains a
decent chance that the shear could relax by the middle of the week,
allowing Philippe to become a hurricane after it recurves into the
subtropical central Atlantic. Guidance has been inconsistent at
long range with the storm, so the best course of action seems to
be to hold the forecast steady to see if any notable trends emerge.


KEY MESSAGES:

1. Tropical storm conditions are possible across portions of the
northern Leeward Islands Monday and Monday night while Philippe
passes near or just northeast of the area, and a Tropical Storm
Watch is in effect for Antigua and Barbuda. Interests elsewhere
in the northern Leeward Islands should continue to monitor this
system as additional watches or warnings could be required later
today or tonight.

2. Heavy rainfall from Philippe could produce isolated to scattered
flash flooding, particularly across Barbuda and Antigua, through
Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT 01/2100Z 16.4N 59.0W 45 KT 50 MPH
12H 02/0600Z 17.0N 59.9W 45 KT 50 MPH
24H 02/1800Z 17.7N 60.8W 45 KT 50 MPH
36H 03/0600Z 18.7N 61.6W 50 KT 60 MPH
48H 03/1800Z 19.9N 62.0W 50 KT 60 MPH
60H 04/0600Z 21.4N 62.2W 50 KT 60 MPH
72H 04/1800Z 23.1N 62.2W 55 KT 65 MPH
96H 05/1800Z 26.9N 61.1W 65 KT 75 MPH
120H 06/1800Z 30.0N 58.0W 75 KT 85 MPH

$$
Forecaster Blake

[cycloneye]

[Div][
BULLETIN
Tropical Storm Philippe Intermediate Advisory Number 34A
NWS National Hurricane Center Miami FL AL172023
800 PM AST Sun Oct 01 2023

...PHILIPPE MOVING SLOWLY...
...HEAVY RAIN AND FLASH FLOOD THREAT BEGINNING OVERNIGHT FOR THE
LEEWARD ISLANDS...


SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...16.6N 59.0W
ABOUT 160 MI...260 KM E OF GUADELOUPE
ABOUT 195 MI...320 KM ESE OF BARBUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Antigua, Barbuda/Div]

[cycloneye]

BULLETIN
Tropical Storm Philippe Advisory Number 35
NWS National Hurricane Center Miami FL AL172023
1100 PM AST Sun Oct 01 2023

...SLOW-MOVING PHILIPPE EXPECTED TO BRING HEAVY RAINS AND FLOODING
TO PORTIONS OF THE LEEWARD ISLANDS LATER TONIGHT AND MONDAY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...16.6N 59.1W
ABOUT 155 MI...245 KM E OF GUADELOUPE
ABOUT 190 MI...310 KM ESE OF BARBUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Antigua, Barbuda

Interests elsewhere in the northern Leeward Islands should monitor
the progress of this system. Additional tropical storm watches
could be required tonight or on Monday.


Tropical Storm Philippe Discussion Number 35
NWS National Hurricane Center Miami FL AL172023
1100 PM AST Sun Oct 01 2023

Philippe's cloud pattern has not become significantly better
organized since earlier today. The system is still producing very
deep convection with cloud tops to -80 deg C or colder mainly over
the southeastern quadrant of the circulation. There are no obvious
curved convective banding features at this time. Some new
thunderstorms have developed near and over the center and this was
noted by the Air Force Hurricane Hunters who have been investigating
the storm this evening. Observations from the aircraft indicate
little change in strength, with peak SFMR-observed surface winds
near 45 kt.

The tropical cyclone has moved rather slowly over the past several
hours and the initial motion estimate is west-northwestward, or
300/4 kt. Philippe should turn northwestward to northward along
the western periphery of a mid-level high pressure area for the
next few days. Then, the system should turn north-northeastward
and move through a weakness in the ridge. The track guidance
through 48 hours has shifted eastward on this cycle. In an attempt
to maintain continuity from the previous forecasts, the NHC track
is not shifted eastward as much as shown by the model consensus,
and the change through 24 hours is fairly slight. Late in the
forecast period, there is uncertainty as to how soon the cyclone
will move into the higher-latitude westerlies. The new GFS model
run suggests that the system may turn eastward and stay in the
subtropics through 5 days. If this turns out to be true, then
Philippe could have a prolonged existence.

The environment for Philippe in the short term does not appear
conducive for significant strengthening, with fairly strong
westerly vertical wind shear likely to continue to affect the
system through Monday. When the system moves farther north over
the Atlantic, it may encounter a region of reduced shear as
indicated by some of the dynamical guidance. The official forecast
still shows the system becoming a hurricane in the 3- to 5-day time
frame and this is also supported by the IVCN model intensity
guidance.


KEY MESSAGES:

1. Tropical storm conditions are possible across portions of the
northern Leeward Islands Monday and Monday night while Philippe
passes near or just northeast of the area, and a Tropical Storm
Watch is in effect for Antigua and Barbuda. Interests elsewhere
in the northern Leeward Islands should continue to monitor this
system as additional watches or warnings could be required later
tonight or Monday.

2. Heavy rainfall from Philippe could produce isolated to scattered
flash flooding, particularly across Barbuda and Antigua, through
Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0300Z 16.6N 59.1W 45 KT 50 MPH
12H 02/1200Z 17.0N 59.8W 45 KT 50 MPH
24H 03/0000Z 17.8N 60.7W 45 KT 50 MPH
36H 03/1200Z 19.0N 61.3W 50 KT 60 MPH
48H 04/0000Z 20.3N 61.7W 50 KT 60 MPH
60H 04/1200Z 22.0N 61.8W 50 KT 60 MPH
72H 05/0000Z 23.8N 61.7W 55 KT 65 MPH
96H 06/0000Z 27.5N 60.2W 65 KT 75 MPH
120H 07/0000Z 30.1N 57.6W 75 KT 85 MPH

$$
Forecaster Pasch

[cycloneye]

Tropical Storm Philippe Discussion Number 36
NWS National Hurricane Center Miami FL AL172023
500 AM AST Mon Oct 02 2023

The overall structure of Philippe has changed very little during the
past day or so. Deep convection remains confined to the
southeastern portion of the circulation due to moderate to strong
northwesterly vertical wind shear. There is no significant banding
features, but the cloud tops within the main convective mass are
quite cold. Radar imagery from Barbados shows very heavy rainfall
is occurring just east of the Lesser Antilles. The initial
intensity is held at 45 kt in deference to the earlier aircraft
data, and the latest subjective Dvorak intensity estimates which are
unchanged from before. The next Air Force Reserve reconnaissance
aircraft mission is scheduled to investigate Philippe later this
morning.

Center fixes during the past 6-12 hours indicate that Philippe has
turned northwestward (315 degrees) and is moving a little faster,
around 6 kt. Philippe is forecast to move around the southwestern
portion of a mid-level ridge over the subtropical Atlantic during
the next couple of days. After that time, Philippe should turn
northward between the aforementioned ridge and a mid- to upper-level
trough over the southwestern Atlantic. Around day 5, there is
increasing uncertainty as to whether Philippe will turn
east-northeastward or continue on a more northerly trajectory ahead
of a large trough moving into the eastern United States. Little
change was made to the previous forecast through 72 hours, but after
that time the track was adjusted northwestward closer to the GFS
ensemble mean. The new track is not as far west as the latest ECMWF
or the multi-model consensus aids.

Strong westerly vertical wind shear is expected to prevent
significant strengthening for about another 12-24 hours. After that
time, Philippe is expected to encounter a more favorable upper-level
wind pattern as it moves northward over the Atlantic. This should
allow for steady strengthening, and much of the guidance predicts
that Philippe will become a hurricane in 3 to 4 days. The NHC
intensity forecast follows suit, and is a blend of the HFIP
corrected consensus model and the multi-model (ICVN) intensity aid.


KEY MESSAGES:

1. Tropical storm conditions are possible across portions of the
northern Leeward Islands through tonight while Philippe passes near
or just northeast of the area, and a Tropical Storm Watch is in
effect for Antigua and Barbuda. Interests elsewhere in the northern
Leeward Islands should continue to monitor this system.

2. Heavy rainfall from Philippe could produce isolated to scattered
flash flooding, particularly across Barbuda and Antigua, through
Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0900Z 17.1N 60.0W 45 KT 50 MPH
12H 02/1800Z 17.7N 60.7W 45 KT 50 MPH
24H 03/0600Z 18.6N 61.4W 45 KT 50 MPH
36H 03/1800Z 19.8N 61.8W 50 KT 60 MPH
48H 04/0600Z 21.2N 62.2W 50 KT 60 MPH
60H 04/1800Z 22.7N 62.3W 55 KT 65 MPH
72H 05/0600Z 24.6N 62.2W 60 KT 70 MPH
96H 06/0600Z 28.3N 60.8W 70 KT 80 MPH
120H 07/0600Z 31.7N 58.9W 75 KT 85 MPH

$$
Forecaster Brown

[cycloneye]

BULLETIN
Tropical Storm Philippe Intermediate Advisory Number 36A
NWS National Hurricane Center Miami FL AL172023
800 AM AST Mon Oct 02 2023

...PHILIPPE COULD BRING HEAVY RAINS AND FLOODING TO PORTIONS OF
THE LEEWARD ISLANDS LATER TODAY...


SUMMARY OF 800 AM AST...1200 UTC...INFORMATION
----------------------------------------------
LOCATION...17.0N 60.5W
ABOUT 95 MI...155 KM ESE OF BARBUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES

[cycloneye]

Tropical Storm Philippe Advisory Number 37
NWS National Hurricane Center Miami FL AL172023
1100 AM AST Mon Oct 02 2023

...TROPICAL STORM WARNING ISSUED FOR BARBUDA...
...PHILIPPE COULD BRING HEAVY RAINS AND FLOODING TO PORTIONS OF
THE LEEWARD ISLANDS LATER TODAY...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...17.1N 60.7W
ABOUT 80 MI...130 KM ESE OF BARBUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The government of Antigua has issued a Tropical Storm Warning for
Barbuda.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Barbuda

A Tropical Storm Watch is in effect for...
* Antigua

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case within 12
hours.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, in this case within 12 hours.

Interests elsewhere in the northern Leeward Islands should monitor
the progress of this system.



Tropical Storm Philippe Discussion Number 37
NWS National Hurricane Center Miami FL AL172023
1100 AM AST Mon Oct 02 2023

The center of Philippe has become exposed this morning with
convection and heavy rainfall displaced to the south and southeast
of the center as high northwesterly vertical wind shear persists.
The initial intensity is held steady at 45 kt for this advisory,
consistent with SFMR data from the Air Force Reserve reconnaissance
aircraft mission showing a large area of 40-45 surface winds.

Center fixes and 1-min visible imagery during the morning indicate
that Philippe is moving erratically to the west-northwest (300
degrees) at 6 kt. The short-term part of track forecast is adjusted
westward to match recent satellite trends, which necessitates the
Tropical Storm Warning for Barbuda. After passing close to that
island, Philippe is forecast to move northwest to north-northwest
around the southwestern portion of a mid-level ridge over the
subtropical Atlantic during the next couple of days. Around
mid-week, Philippe should turn northward between the aforementioned
ridge and a mid- to upper-level trough over the southwestern
Atlantic. Beyond 96 hours, track uncertainty increases as to
whether the ridge or trough will dominate, which is also partially
connected to how strong Philippe becomes. Stronger solutions take
the system on a more east-northeastward track at longer range while
weaker solutions take the system more northward. Overall, the track
forecast for this advisory was adjusted farther west than the
previous advisory, after considering the latest ECMWF and ensemble
aids.

Strong northwesterly vertical wind shear is expected to prevent
significant strengthening in the short term. In a couple of days,
Philippe is expected to encounter a more favorable upper-level wind
pattern as it moves northward over the Atlantic. This could allow
for steady strengthening, and much of the guidance predicts that
Philippe will become a hurricane in 3 to 4 days. The intensity
forecast is consistent with the consensus aids, although the
uncertainty is pretty high at long range given how Philippe has so
far refused to intensify for days now.


KEY MESSAGES:

1. Tropical storm conditions are expected across Barbuda and
possible across Antigua beginning this evening while Philippe passes
near or just northeast of the area. Interests elsewhere in the
northern Leeward Islands should continue to monitor this system.

2. Heavy rainfall from Philippe could produce isolated to scattered
flash flooding over the northern Leeward Islands, particularly
across Barbuda and Antigua, through Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT 02/1500Z 17.1N 60.7W 45 KT 50 MPH
12H 03/0000Z 17.8N 61.5W 45 KT 50 MPH
24H 03/1200Z 18.9N 62.0W 50 KT 60 MPH
36H 04/0000Z 20.2N 62.4W 50 KT 60 MPH
48H 04/1200Z 21.8N 62.7W 50 KT 60 MPH
60H 05/0000Z 23.5N 62.8W 55 KT 65 MPH
72H 05/1200Z 25.3N 62.9W 60 KT 70 MPH
96H 06/1200Z 29.2N 61.5W 70 KT 80 MPH
120H 07/1200Z 32.5N 59.5W 75 KT 85 MPH

$$
Forecaster Blake/Stevenson