[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191706
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Tue Sep 19 2023

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 1200 UTC surface analysis and satellite imagery through
1655 UTC.

...SPECIAL FEATURES...

Hurricane Nigel is near 30.5N 54.3W at 11 AM EDT, and is moving
north-northwest at 14 kt. Maximum sustained winds are 80 kt with
gusts to 100 kt, and the minimum central pressure is 975 mb. Seas
are peaking to near 34 ft near and just NE of the center. Satellite
imagery continue to depict a large eye surrounded by deep
convection, especially from 28N to 34N and between 51W and 58W.
The hurricane is forecast to turn northward late today, and then
accelerate rapidly northeastward through the rest of the week.
Nigel could strengthen some more through early Wednesday, but
weakening is likely on Thursday and Friday. Nigel is forecast to
become a strong post- tropical cyclone on Friday. Swells generated
by Nigel are expected to reach Bermuda later today. These swells
are likely to cause life- threatening surf and rip current
conditions. Please consult products from your local weather
office.

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 Nigel
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave has its axis along 24W, south of
19N, moving westward at 10-15 kt. Scattered moderate convection is
noted near the monsoon trough from 05N to 08N and between 20W and
27W.

A central Atlantic tropical wave has its axis along 45W, south of
14N, moving westward at 10-15 kt. Numerous moderate to isolated
strong convection is observed from 06N to 11N and between 41W and
48W.

...MONSOON TROUGH/ITCZ...

The monsoon trough reaches the Atlantic through the coast of
Senegal near 15N17W and continues southwestward to 09N30W and then
westward to 09N47W. The ITCZ extends from 09N47W to 07N58W. Other
than the convection described in the TROPICAL WAVES section
above, scattered moderate to isolated strong convection is present
from 03N to 14N and between 29W and 41W. Similar convection is
seen from 06N to 12N and between 48W and 54W.

...GULF OF MEXICO...

A stationary front remains draped across the Gulf of Mexico,
extending from SW Florida to near 25N95W. Scattered moderate to
isolated strong convection is noted within 120 nm of the frontal
boundary. Gentle to moderate easterly winds and seas of 2-4 ft are
evident north of the front. Light to gentle winds and seas of 1-3
ft are found south of the boundary. However, a recent
scatterometer satellite pass indicate that fresh to strong winds
are occurring with the strongest convection.

For the forecast, a stationary front extends from South Florida
across the central Gulf to near 25N95W. The front will slowly
dissipate through this evening. Then, a ridge will dominate the
basin producing gentle to moderate E to SE winds and slight seas,
pulsing to moderate to fresh offshore the W Yucatan in the
evenings. Building high pressure north of the area could bring
fresh winds and building seas over the NE Gulf by the end of the
week.

...CARIBBEAN SEA...

Divergent flow associated with an upper level trough located in
the NW Caribbean Sea and abundant tropical moisture continue to
support scattered showers and a few thunderstorms in the southern
Caribbean, especially south of 16N and west of 75W. No deep
convection is noted in the rest of the Caribbean.

A weak pressure gradient sustains mainly moderate to fresh
easterly trade winds in the central Caribbean. However, strong
winds are occurring just off the northern Colombian coast. Seas
in the central Caribbean are 4-6 ft. Elsewhere, light to gentle
winds and seas of 2-4 ft prevail.

For the forecast, long period north to northeast swell will impact the
Caribbean passages and Tropical N Atlantic through early Wed.
Moderate to fresh trades will prevail in the central Caribbean,
locally strong at times offshore northern Colombia and northwest
Venezuela, with moderate or weaker winds elsewhere through the
week.

...ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for details on Hurricane
Nigel.

A stationary front extends southwestward from 31N71W to SE
Florida, resulting showers and isolated thunderstorms to the
north of the boundary. Moderate or weaker winds and 2-4 ft seas
are found behind the frontal boundary. The remainder of the
Atlantic is dominated by a broad subtropical ridge positioned near
the Azores. The pressure gradient between the aforementioned 1025
mb high pressure system and lower pressures in the deep tropics
support fresh to strong easterly winds winds east of 45W and north
of 15W. Seas in these waters are 6-9 ft. Elsewhere, moderate or
weaker winds and moderate seas prevail.

For the forecast W of 55W, Hurricane Nigel is near 30.5N 54.3W at
11 AM EDT, and is moving north-northwest at 14 kt. Maximum
sustained winds are 80 kt with gusts to 100 kt, and the minimum
central pressure is 975 mb. Nigel will move N of area to near
32.3N 54.7W this evening. Strong winds and rough seas associated
with Nigel will continue to affect the forecast waters through
late Wed or Wed evening. A stationary front extending from near
31N71W to South Florida will change little through Thu. The
boundary should begin to slowly lift northward on Fri as low
pressure develops along it to the east of northern Florida. Winds
and seas will likely increase in that area by the end of the week
as a tight pressure gradient develops between the developing low
pressure off the Carolinas and high pressure inland over the U.S.
Gale- force northerly winds are expected off the southeastern U.S.
coast Fri through Sat.

$$
DELGADO
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