[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230535
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Thu Sep 23 2021

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0525 UTC.

...SPECIAL FEATURES...

Peter is no longer a tropical depression. At 23/0300 UTC, the
remnants of Peter were centered near 22.1N 67.0W or about 225 nm
NNW of San Juan Puerto Rico moving NNW at 4 kt. Estimated minimum
central pressure is 1008 mb. Maximum sustained wind speed is 25 kt
with gusts to 35 kt. Strong wind shear continues to displace the
convection to the east of the center. Peak seas are currently near
8 ft and similar seas are expected over the next few days near
the track of the remnant low. The remnants are expected to move
generally northward over the next couple of days. Gradual
weakening is forecast over the next couple of days. Please, read
the read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website-
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Peter
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Tropical Depression Rose was centered near 24.6N 40.9W at 23/0300
UTC or about 1080 nm WNW of the Cabo Verde Islands moving WNW at
9 kt. Estimated minimum central pressure is 1010 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Rose is a swirl
of low- level clouds, with the only significant convection
occurring about 120 nm southeast of the center. Peak seas are
currently near 11 ft and are forecast to decrease below 8 ft by
Friday morning. The depression is moving toward the west-
northwest. but a northwestward motion is expected tonight, with a
turn toward the north forecast by Thursday night. A motion toward
the northeast is expected on Friday. Gradual weakening is forecast
during the next couple of days, and Rose is expected to
degenerate to a remnant low pressure area by early Thursday.
Please, read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website-
https:/www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Rose
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Tropical Depression Eighteen was centered near 10.2N 35.0W at
23/0300 UTC or about 1700 nm ESE of the N Leeward Islands moving
W at 13 kt. Estimated minimum central pressure is 1008 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Numerous
moderate to isolated strong convection is occurring 200 nm of the
center, mainly in the northern semicircle. Peak seas are currently
near 12 ft and are forecast to increase to near 16 ft by Friday
morning. The depression is moving toward the west and this general
motion is expected to continue through early Friday. A slower
motion toward the west- northwest is expected later on Friday and
continuing into the weekend. The depression could intensify to a
tropical storm on Thursday and to a hurricane over the weekend.
Please, read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website-
https:/www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest T.D.
Eighteen NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

A gale-force, non-tropical low pressure system, the remnants of
Odette, is located more than 520 nm WNW of the westernmost
Azores. Showers and thunderstorms have increased a little near the
low, and it could become a subtropical or tropical cyclone while it
moves generally southward over marginally warmer waters during the
next couple of days. Strong upper-level winds are expected to
develop over the system this weekend, which should limit its
development. Additional information on this system, including gale
warnings, can be found in the latest High Seas Forecast issued by
the Ocean Prediction Center at website-
https://ocean.weather.gov/mobile/mobile_product.php?=idNFDHSFA1.
This system has a medium chance of subtropical or tropical cyclone
formation through 48 hours. Please, see the latest Tropical
Weather Outlook at www.hurricanes.gov for more details.

...TROPICAL WAVES...

At this moment, no tropical waves are in the analysis/surface
map between W Africa and the Lesser Antilles, and across the
Caribbean Sea.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the Mauritania-Senegal border
near 16N16W and then continues SW and W to 08N30W. The ITCZ
extends from 05N40W to 05N52W in the coast of French Guiana.
Scattered moderate convection is noted well south of the monsoon
trough from 04N to 11N and between 27W to the coast of Africa. No
significant convection is noted in association with the ITCZ.

GULF OF MEXICO...

An early season cold front is moving across the Gulf region and
extends from the Florida panhandle near Apalachicola to near
Tuxpan, Mexico. Fresh to strong northerly winds are observed behind
the frontal boundary in a recent scatterometer satellite data and
buoy and ships reports, affecting most of the N Gulf. Fresh to
strong northerly winds are also occurring in the SW Gulf,
especially within 100 nm of the coast of Veracruz. Scattered
showers with embedded thunderstorms are noted within 150 nm of the
coast of Tamaulipas from 21N to 25N. The southerly flow will
persist today across South Florida and the SE Gulf as the frontal
boundary slows down, keeping the region unstable with a high
chance of showers and thunderstorms developing again later today,
especially in the afternoon and evening hours. Seas behind the
cold front are 4-7 ft and 2-4 ft ahead of the cold front.

For the forecast, the cold front will continue to move
southeastward through Thu, stall from roughly Fort Myers, Florida
to the coast of Veracruz, Mexico near 18N95W Fri, then dissipate
Sat. Fresh to strong winds will follow the front over the
northwest and north- central Gulf into tonight. Fresh to strong
winds will funnel along the coast of Veracruz Thu, with seas
building to 9 ft. Looking ahead, winds and seas will diminish
across basin from Sat and into early next week as high pressure
builds over the northern Gulf.

CARIBBEAN SEA...

Please read the Special Features section above for details on
the Remnants of Peter located NNW of San Juan Puerto Rico.

The thunderstorm activity that developed in the afternoon and
evening hours across the islands in the W Caribbean has generally
dissipated. Overall, no deep convection is noted across the
basin. However, showers and thunderstorms continue to affect parts
of Costa Rica, Panama and N Colombia, with most of convection on
their Pacific coasts. The weak pressure gradient due to the
remnants of Peter just north of basin and typical lower pressures
over South America results in gentle to moderate trades across the
region as observed in a recent scatterometer satellite pass. Seas
in the E Caribbean are 2-4 ft, and 1-2 ft elsewhere.

For the forecast, Tropical Depression Eighteen is well to the
east over the Tropical Atlantic near 10.2N 35.0W 1008 mb at 0300
UTC moving W at 13 kt. Maximum sustained winds 30 kt gusts 40 kt.
Eighteen will continue to intensify as it moves across the
Atlantic, becoming a hurricane near 12.5N 46.0W by Sat morning
and, reaching 55W east of the Leeward Islands by Mon. Meanwhile,
moderate trade winds will persist over much of the Caribbean into
early next week, becoming fresh over the south-central Caribbean
Sun and Mon.

ATLANTIC OCEAN...

Please read the Special Features section above for details on
the Remnants of Peter, and Tropical Depressions Rose and
Eighteen.

The Cumbre Vieja volcano on the island of La Palma in the Canary
Islands has been erupting since 19/1410 UTC. The volcano is still
emitting ashes, mainly around the volcano drifting SSW below
10,000 ft, and NE above 10,000 ft. Marine and aviation interests
should monitor this on-going situation by reading Volcanic Ash
Advisory issued by Meteo-France at http://vaac.meteo.fr/volcanoes
/la-palma/. The next advisory will be issue no later than 23/0900
UTC.

A stationary front extends from 31N44W to 27N60W to 31N78W to the
coast of South Carolina. An upper level low near Bermuda is
interacting with the frontal boundary and the tropical moisture
being propelled northward by the remnants of Peter, resulting in
scattered showers and a few thunderstorms from 24N to 31N and
between 55W and 68W. The E Atlantic remains under the influence of
a strong 1033 mb ridge positioned N of the Azores. Satellite-derived
wind data indicate fresh NE winds off the coast of Mauritania and
the surrounding waters of the Cabo Verde Islands, mainly from 16N
to 21N and E of 27W. This is associated with an outbreak of dry
Saharan air. Gentle to moderate anticyclonic winds prevail in the
rest of the basin. Seas of 3-6 ft are prevalent W of 60W and 4-7
ft E of 60W.

For the forecast west of 65W, the remnant low of Peter is near
22.1N 67.0W 1008 mb at 0300 UTC moving NNW at 4 kt. Maximum
sustained winds are 25 kt with gusts to 35 kt. This low will
continue to weaken as it drifts northeast of the region through
Sat cold front will move off the northeast Florida coast tonight,
continue to the southeast Thu, stall from 31N77W to near Fort
Pierce, Florida by late Thu, then dissipate through early Sun just
before a second weak front possibly moves into the region early
next week. Farther east, Tropical Depression Eighteen is over the
Tropical Atlantic near 10.2N 35.0W 1008 mb at 0300 UTC moving W at
13 kt. Maximum sustained winds 30 kt gusts 40 kt. Eighteen will
continue to intensify as it moves across the Atlantic, becoming a
hurricane near 12.5N 46.0W by Sat morning and, reaching 55W east
of the Leeward Islands by Mon.

$$
DELGADO
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