[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172130
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 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 1800 UTC surface analysis and satellite imagery through
1915 UTC.

...SPECIAL FEATURES...

Central Tropical Atlantic (AL94) Gale Warning: Satellite images
indicate that a broad area of low pressure located about 1100
nautical miles east of the Windward Islands has become better
defined since this morning, and the associated showers and
thunderstorms are also showing signs of organization. Current
associated winds are 20-30 kt with seas of 8-11 ft. Numerous
moderate isolated strong convection is noted from 04N to 16N
between 37W and 49W, and from 17N to 19N between 45W and 49W.
Environmental conditions are expected to remain conducive for
gradual development, and a tropical depression will likely form
during the next day or two while the system moves westward to
west-northwestward across the central and western tropical
Atlantic. Interests in the Lesser Antilles should monitor the
progress of this system. Additional information, including gale
warnings, can be found in High Seas Forecasts issued by the
National Weather Service. Regardless of development, this system
has the potential to bring gusty winds, heavy rainfall and
flooding to portions of the Lesser Antilles beginning Friday.
This disturbance has a high chance of tropical cyclone formation
through the next 48 hours. Please refer to the latest NHC Tropical
Weather Outlook at www.hurricanes.gov for more details.
Additional information, regarding the Gale Warning, can be found
in High Seas Forecasts issued by the National Weather Service.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic through the coast at the
border of Mauritania and Senegal near 16N16W to 05N31W to low
pressure (AL94) near 11.5N43.5W to 10N51W. Other than the
convection associated with AL94 described in the Special Features
section above, scattered moderate isolated strong convection is
noted from 03N to 09N between 16W and 20W, and from 00N to 07N
between 25W and 37W.

...GULF OF MEXICO...

The Gulf of Mexico remains under the influence of a 1021 mb high
pressure system extending from the U.S. Great Plains southward to
Heroica Veracruz, Mexico, allowing for a dry continental airmass
to dominate the basin. Mainly moderate N-NE winds dominate the
basin, locally fresh offshore Veracruz, Mexico. Seas are around
5-8 ft in old northerly swell S of 24N, and 2-5 ft N of 24N.

For the forecast, high pressure will continue to dominate the
Gulf waters the remainder of the work-week. As the high pressure
moves toward the SE of the United States, winds will veer to NE
and E over the E and central Gulf, and to the SE and S over the
western Gulf. Under this pattern, expect mainly gentle to moderate
winds and slight to moderate seas. A frontal system will bring
moderate to fresh westerly winds for the NE Gulf on Fri.

...CARIBBEAN SEA...

A stationary front extends from eastern Cuba to the Gulf of
Honduras. Satellite imagery continues to depicts scattered
showers and thunderstorms near the frontal boundary within about
60 nm either side of the front, as well as off the coast of
Nicaragua, and between Jamaica and eastern Cuba. Scattered showers
and thunderstorms are also seen from 10N to 18N between 75W and
80W in association to deep layer trough.

To the northwest of the stationary front, moderate to locally fresh
north winds are occurring, along with seas 5-7 ft, locally 8 ft
near the Yucatan Channel. Moderate to locally fresh easterly
trade winds are evident in the south-central Caribbean along with
3-5 ft seas, with similar winds nearshore Nicaragua due to a
locally tight pressure gradient somewhat associated with the
stationary front. Seas are 1-3 ft elsewhere SE of the stationary
front. Light to gentle winds prevail across the remainder of the
waters.

For the forecast, the front should remain in place through Wed
before dissipating Wed night. Fresh NE winds and moderate seas
will persist over the northwest Caribbean through Wed as high
pressure builds over the area. Looking ahead, a broad area of low
pressure (AL94) located about 1100 nautical miles east of the
Windward Islands has become better defined since this morning, and
the associated showers and thunderstorms are also showing signs
of organization. Now, it has a high chance of tropical cyclone
formation trough 48 hours. Interests in the Lesser Antilles should
monitor the progress of this system.

...ATLANTIC OCEAN...

Please see the SPECIAL FEATURES section above for more details on
Invest 94L.

A stationary front extends from 31N64W to across the SE Bahamas to
eastern Cuba. A clusters of scattered thunderstorms are noted
along and within 150 nm SE of the front. Moderate to fresh winds
and seas 6-9 ft are occurring from 27N to 31N between 55W and
75W. Winds are mainly gentle farther south, to the north of
eastern Cuba, Hispaniola and Puerto Rico.

Farther east, an 1011 mb low associated with the remnants of Sean
and is located near 19.5N59W along a NE to SW surface trough from
25N56W to 16N60W. Associated scattered showers and isolated
thunderstorms are noted from 19N to 25N within 180 nm W of the
trough where winds are moderate to fresh with seas of 5-7 ft. A
surface ridge extends from 30N25W to 1019 mb high pressure near
27N42W to 24N69W. Light to gentle winds and 5-7 ft seas are near
the ridge axis. In the far NE part of the area, north of 29N and
east of 27W, large swell of 7-10 ft is subsiding, due to a
departing storm system far to the north. Gentle to moderate winds
and 4-7 ft seas prevail across the remainder of the open waters.

For the forecast W of 55W, the front will remain in place before
dissipating Wed night or Thu. Expect fresh winds over waters north
of 25N through this morning, on both sides of the front. Winds
and seas will diminish tonight as high pressure builds over the
area in the wake of the front. Looking ahead, 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. A broad area of
low pressure (AL94) located about 1100 miles east of the Windward
Islands has become better defined since this morning, and the
associated showers and thunderstorms are also showing signs of
organization. Now, it has a high chance of tropical cyclone
formation trough 48 hours. Interests in the Lesser Antilles should
monitor the progress of this system.

$$
Lewitsky
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