[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181751
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Wed Oct 18 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
1745 UTC.

...SPECIAL FEATURES...

Central Tropical Atlantic (AL94) Storm Warning: A 1008 mb low
pressure system is located about 600 nm east of the Windward
Islands, near 12.4N48.6W. Numerous moderate to scattered strong
convection is evident on satellite imagery from 05N to 14N and
between 43.5W and 52W. Satellite-derived wind data indicated that
the system is already producing winds to tropical storm force.
Seas of 8-14 ft are found from 10N to 21N and between 44.5W and
54W. Continued development is anticipated, and a tropical storm is
expected to form later today or tonight while moving westward or
west-northwestward toward the Lesser Antilles. Regardless of
development, this system has the potential to bring gusty winds,
heavy rainfall, and flash flooding to portions of the Lesser
Antilles beginning on Friday. The chance of tropical cyclone
formation within the next 48 hours is high. Please refer to the
latest NHC Tropical Weather Outlook at www.hurricanes.gov for more
details. A gale warning is already in effect in association with
AL94. Additional information regarding the Gale and Storm Warnings
can be found in the latest HIGH SEAS FORECAST issued by the
National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml

...MONSOON TROUGH/ITCZ...

The monsoon trough reaches the Atlantic through the coast of
Guinea-Bissau near 11.5N16W and continues southwestward to 04N27W
to 03N38W. The ITCZ extends from 03N38W to 01N50W. Scattered
moderate to isolated strong convection is observed within 150 nm
N and within 390 nm S of both axes.

...GULF OF MEXICO...

A 1019 mb high pressure is centered along the southeast coast of
Louisiana. This high pressure is dominating the sensible weather
in the Gulf of Mexico. As dry continental airmass enveloping the
basin is suppressing the development of deep convection. However,
a weak surface trough in the Bay of Campeche allows for shallow
showers in the area. Light to gentle anticyclonic winds prevail
over the northern Gulf with 1 to 3 ft seas. Moderate NE winds are
over the southern Gulf with seas of 3 to 6 ft.

For the forecast, the aforementioned high pressure will continue
to dominate the Gulf waters through Thu night. Gentle to moderate
anticyclonic winds will prevail through Thu night. A frontal
system will bring fresh winds to the NE Gulf Fri and Fri night.
Benign conditions will then return over the weekend as high
pressure builds back in.

...CARIBBEAN SEA...

A stationary front extends from eastern Cuba to NE
Honduras. Scattered moderate to strong convection is along the front to
the east of 86.5W. Similar activity is noted within 150 nm of the
coast of Nicaragua, Costa Rica, and Panama. Fresh to strong NE
winds and seas of 5 to 8 ft are occurring over the western
Caribbean. Gentle to moderate winds prevail over most of the
basin, east of the stationary front, except for fresh trades in
the south- central Caribbean. Seas are 4 to 5 ft in the south-
central Caribbean, and 2 to 4 ft elsewhere east of the stationary
front.

For the forecast, the aforementioned stationary front should
remain in place through today before dissipating tonight. Fresh to
locally strong NE winds and seas of 6 to 8 ft will persist over
the northwest Caribbean through today as high pressure builds over
the area. Looking ahead, a broad area of low pressure located
about 850 miles east of the Windward Islands continue to show
signs of organization. It has a high chance of tropical cyclone
formation through 48 hours. Interests in the Lesser Antilles
should monitor the progress of this system, and watches may be
required for some of the islands later today.

...ATLANTIC OCEAN...

Please see the Special Features section above for more details on
Invest 94L located well east of the Lesser Antilles.

A stationary front remains draped across the western Atlantic from
31N62W to eastern Cuba. Scattered moderate to isolated strong
convection is noted along the front. The strongest convection is
depicted from 26N to 31N between 66W and 71.5W. It is in this area
where recent scatterometer data revealed that winds are out of
the north and near-gale. A surface trough extends from 31N68W to
29N74W. Another surface trough extends northeastward from the
Virgin Islands to 25N62W. Scattered moderate thunderstorms are
within 70 nm of the trough axis. Outside of convection, west of
65W, winds are gentle to moderate and seas are 3 to 6 ft.

An upper-level low east of the Lesser Antilles is producing
scattered to isolated strong convection from 17N to 22N between
52W and 58W. Recent scatterometer data revealed that winds are
strong to near-gale in association with the convection.

Farther east, broad ridging is leading to gentle winds from 25N
to 31N between 29W and 60W, anchored by a 1022 mb high pressure
centered near 27.5N46W. Seas are 5 to 7 ft across the area. To
the south of 25N and east of 62W, moderate to fresh winds and
seas of 6 to 8 ft cover much of the area, but these winds and seas
increase closer to AL94.

For the forecast W of 55W, the aforementioned stationary front
will remain in place before dissipating Thu. High pressure will
build over the area in the wake of the front. The next frontal
system will move offshore the southeastern United States Fri
night. Fresh to strong winds and rough seas are forecast north of
27N Fri night through Sat night with this system. Looking ahead, a
broad area of low pressure located about 850 miles east of the
Windward Islands continue to show signs of organization. It has a
high chance of tropical cyclone formation through 48 hours.
Interests in the Lesser Antilles should monitor the progress of
this system, and watches may be required for some of the islands
later today.

$$
KRV
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