[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181045
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through
1030 UTC.

...SPECIAL FEATURES...

Central Tropical Atlantic (AL94) Storm Warning: A 1008 mb low
pressure system is located several hundred miles east of the
Lesser Antilles, near 12N46W. Numerous moderate to scattered
strong convection is evident on satellite imagery from 05N to 14N
and between 43W and 51W. Strong to near gale-force winds are
occurring in all quadrants except the SW quadrant. Seas of 8-12 ft
are found from 09N to 21N and between 42W and 52W. ASCAT and
altimeter passes from Tue evening measured winds to 32 kt and seas
to 11 ft, but these satellite passes may not have captured the
peak conditions. Environmental conditions are expected to remain
conducive for gradual development, and a tropical depression or
storm is likely to form during the next day or so while the
system moves westward to west-northwestward across the central and
western tropical Atlantic. Regardless of development, this system
has the potential to bring gusty winds, heavy rainfall, and
flooding to portions of the Lesser Antilles beginning 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. TAFB is forecasting this
system to develop gale force winds later this morning, and storm
force winds by late Thu night or early Fri morning. Seas near the
center will build to near 20 ft by early Fri morning. Additional
information regarding the Storm Warning 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 12N16W and continues southwestward to 05N24W to
04N38W. The ITCZ extends from 04N38W to 08N45W. Scattered
moderate to isolated strong convection is observed within 180 nm N
and within 300 nm S of both axes.

...GULF OF MEXICO...

1020 mb high pressure is centered along the southeast coast of
Louisiana. The high pressure dominates the Gulf of Mexico. A 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, high pressure will continue to dominate the
Gulf waters through Thu night. Gentle to moderate anti-cyclonic
winds will prevail through Thu night. A frontal system will bring
fresh winds to the NE Gulf Fri through Fri night. Benign
conditions will then return over the weekend as high pressure
builds back in.

...CARIBBEAN SEA...

A stationary front stretches from eastern Cuba near 20N77W to
16.5N82.5W to 16N88W at southern Belize. Scattered moderate to
strong convection is along the front to the east of 86W. Similar
activity is noted within 90 nm of the coast of Nicaragua and Costa
Rica. Isolated tstorms are also seen from 09N to 16N between 76W
and 81.5W. Fresh to strong NE winds and seas of 7 to 8 ft are
occurring over the NW Caribbean, to the NW of the stationary
front.

An upper-level low is over the E Caribbean. A surface trough is
just N of the northernmost Leeward Islands, over the Atlantic.
Isolated showers and tstorms are near the northern Leeward and
Virgin Islands. 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 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.
Scattered thunderstorms are expected through today near and just
to the southeast of the frontal boundary. Looking ahead, Invest
AL94 could affect the Leeward Islands Fri into Sat. See the
Special Features section above for more info.

...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
31N63W to eastern Cuba near 21N76W. Scattered moderate
thunderstorms are noted along and within 60 nm NW of the front. A
surface trough extends from 31N69W to 28N77W. Another surface
trough extends northeastward from the northernmost Leeward Islands
from 18N62W to 26N60W. Scattered moderate thunderstorms are within
120 nm of the trough axis. Over the western Atlantic, to the west
of 63W, winds are gentle to moderate and seas are 4 to 6 ft.

Farther east, broad ridging is leading to gentle winds from 26N to
31N between 30W and 60W, anchored by a 1023 mb high pressure
centered near 27.5N44W. Seas are 5 to 6 ft across the area. To the
south of 25N and east of 62W, 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 stationary front extending from
31N63W to eastern Cuba 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

$$
Hagen
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