[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Oct 11 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 2315 UTC surface analysis and satellite imagery through
1800 UTC.

...SPECIAL FEATURES...

Northern Gulf of Mexico and Western Atlantic Ocean Gale Warning:
Low pressure of 999 mb is centered over the NW Gulf near 28N93W.
A trough extends from the low south-southwestward to 24N94W and
to near 19N96W. A warm front extends from the low eastward to
29N87W and to inland central Florida crossing the coast near
Tampa. ASCAT data from this afternoon highlighted gale-force
northeast 30-40 kt winds along and within 30 nm north of the warm
front and north to northeast gale-force winds of 30-35 kt are
west-northwest of the low to near 94W. Strong to near gale force
northeast winds are elsewhere north of the warm front. The ASCAT
data also showed strong to near gale-force south to southwest
winds south of the warm front to near 24N, and fresh to strong
south to southwest winds from 22N to 24N between the trough and
87W. Seas are 8-11 ft west of the low and trough and 8-9 ft north
of the warm front. The ASCAT data showed fresh to strong
southwest to west winds west of the trough to 95W and south to
near 23N. Buoy 42002 at 26N93.5W is currently reporting seas to
10.5 ft. Satellite imagery shows numerous moderate to strong
convection along and south of the warm front to near 23N. This
activity is producing frequent lightning and strong wind gusts.

The aforementioned low pressure and front are forecast to move
northeast to east across the north-central and NE Gulf this
evening, then inland across northern Florida tonight. Scattered
to numerous strong thunderstorms and strong to gale- force winds
will accompany this low pressure system and frontal boundary
across the northern Gulf through tonight. Seas are expected to be
at 11 or 12 ft this evening. The low pressure is expected to
track eastward across northern Florida tonight, and continue
eastward and emerge over the western Atlantic, bringing strong to
near gale-force winds east of northern and central Florida
tonight into Thu, then shift to east of 75W Thu night, and across
the northeast waters Fri through early Sat. Gale-force winds are
forecast to affect the northern offshore waters north of 30N
through Thu night and north of 27N Fri through Fri evening. Heavy
showers and rough seas are expected with this frontal system.

Please read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at the website -
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for details.

Tropical Storm Sean is centered near 11.6N 35.3W at 11/2100 UTC
or 710 nm WSW of the Cabo Verde Islands, moving WNW at 11 kt.
Estimated minimum central pressure is 1006 mb. The maximum
sustained wind speed is 35 kt with gusts to 45 kt. Peak seas
are presently to 14 ft. Latest satellite imagery shows that Sean
is not well organized. Its center is observed to be on the west
side of a broken band that consists of numerous moderate to
isolated convection roughly from 11N to 12N between 33W-35W. Sean
is forecast to assume a west- northwestward to northwestward
motion is forecast during the next few days. Little change in
strength is forecast during the next 72 hours.

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

...TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis along 20W from
03N to 17N, moving westward 10 kt. A 1010 mb low is located on
the wave near 09N. Scattered moderate convection is within 60 nm
of 12N22W. This convection has changed little in organization
this afternoon, but environmental conditions appear conducive for
some slow development over the next few days. This system should
move generally westward across the eastern and central tropical
Atlantic through early next week.

The earlier tropical wave that had moved inland Central America
is now over the eastern Pacific. Please see the East Pacific
Tropical Weather Discussion (MIATWDEP) for details on this wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis passes through the coastal plains border
areas of Senegal and The Gambia southwestward to the Invest-
AL94 1010 mb low pressure center and continues to 10N28W where
it pauses east of Tropical Storm Sean. It resumes southwest of
Sean near 09N40W to 09N46W, where latest scatterometer data
indicates that it transitions to the ITCZ to 10N57W. Scattered
moderate convection is within 60 nm south of the trough between
17W-19W.

...GULF OF MEXICO...

Please read the Special Features section for details about the
ongoing gale event related to low pressure of 999 mb presently
over the NW Gulf.

A warm front extends from the western Atlantic to across central
Florida to near Tampa, and continues westward to a 999 mb low
over the NW Gulf near 28N93W. A trough extends from the low
south-southwestward to 24N94W and to near 19N96W. Broad low
pressure associated with the 999 mb low is over the western and
central sections of the Gulf. A weak pressure gradient is over
the eastern Gulf. Outside those conditions as described above
under the Special Features section, moderate to fresh southerly
winds are south of 22N east of the trough to near 87W, and gentle
to moderate west to northwest winds are west of the trough from
22N to 23N, and light to gentle northwest winds are south of 22N.
Mostly moderate to fresh southeast to south winds are over the
eastern Gulf south of 28N, and fresh east winds are north of 28N,
except for fresh to strong east winds between 85W-90W. Seas are
4-5 ft over the eastern Gulf south of 28N and 5-7 ft north of
28N.

For the forecast, the low pressure and front will move northeast
to east reaching the NE Gulf this evening and inland north
Florida tonight. High pressure across the Atlantic will build
modestly westward into the eastern Gulf Fri through early Sat,
before the next cold front moves into the NW Gulf Sat morning and
across the entire basin by Sun evening.

...CARIBBEAN SEA...

A rather weak pressure pattern remains over the basin. Moderate
to fresh east-southeast winds are over most of the basin, except
for lighter winds of gentle to moderate speeds over the
northeast and northwest parts and light to gentle in the
southwestern part of the basin. Generally moderate seas are
east of 80W, and slight seas are west of 80W.

Subsidence taking place over the vast majority of the basin
is inhibiting deep convective activity from developing. Isolated
showers and thunderstorms are noted west of 81W and in the
southwest part of the sea.

For the forecast, moderate to fresh trade winds across the
eastern and central Caribbean will diminish to gentle to moderate
Fri morning and prevail through Mon night. Fresh to strong
southeast to south in the Gulf of Honduras and NW Caribbean will
continue through Fri night.

...ATLANTIC OCEAN...

Please,read the Special Features section for details about
Tropical Storm Sean and on upcoming western Atlantic gale event.
Please read the Tropical Waves section for details about the
Invest-AL94 low and associated tropical wave.

A cold front extends from near 31N49W to 29N62W, where it
transitions to stationary front to 29N73W, and continues as a
warm front to inland central Florida near Melbourne. Broken to
overcast multilayer clouds with pockets of scattered showers and
thunderstorms moving eastward are seen north of 24N and west of
45W. Weak high pressure is present over the remainder of the
area. A weak surface trough extends from near 31N30W to 27N40W.
Numerous moderate to strong convection is east of the trough to
near 25N and north of 26N. This activity is quickly shifting
eastward.

Mostly moderate to some fresh winds are from 26N northward
between 45W-60W. Moderate or lighter winds are over the
rest of basin. Mostly moderate to some rough seas are north
of 26N between 30W-40W. Mostly moderate to slight seas are in
the remainder of the Atlantic Ocean.

For the forecast W of 55W, aside from the forecast concerning
the upcoming western Atlantic gale-force event as described
above under Special Features, high pressure will briefly build
over the western Atlantic in the wake of the gale event low
pressure system, but then a cold front is expected to reach the
waters off northeastern Florida Sat and Sat night, followed by
moderate to fresh west winds and seas of 3-5 ft.

$$
Aguirre
This weather bulletin was brought to you by:
www.nashvilleweather.net