[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261800
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Thu Oct 26 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
1900 UTC.

...SPECIAL FEATURES...

Storm Force Wind Warning: Post-Tropical Cyclone Tammy is centered
near 31.0N 59.0W at 26/1200 UTC or 305 nm ESE of Bermuda, and
drifting west-northwestward around 5 kt. Estimated minimum
central pressure is 978 mb. Storm to hurricane force winds and
seas of 28 to 31 ft are present from 30N to 32N between 59W and
62W. Gale to strong gale S to W to NW winds and 22 to 28 ft seas
are evident from 29N to 30N between 59W and 62W. Scattered
showers are noted near and southwest of the center north of 27N
between 58W and 68W. Tammy is expected to drift generally westward
and gradually weaken over the next couple of days.

Western Atlantic Very Rough Seas: Tight pressure gradient between
strong high pressure of 1027 mb over the U.S. Mid-Atlantic coast
and Post-Tropical Cyclone Tammy will continue to support a large
area of strong to near-gale force NE winds and large swell from
20N to 31N between the east coast of Florida and 65W, and also
from 20N to 29N between 50W and 65W through Friday. Seas in the
first area range from 9 to 18 ft, and are 9 to 22 ft in the second
area. Mariners should either avoid this region or use extreme
caution in this area, depending on your vessel type and cargo.
Hazardous surf and rip currents are also anticipated along the
coast of central Florida, the Bahamas, Greater Antilles and the
northern Leeward Islands.

Please read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at the website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the Offshore
Waters Forecast at
https://www.nhc.noaa.gov/marine/offshores.php for more details.

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic along the coast near the
Gambia/Guinea border, then continues southwestward to near
07.5N22W. An ITCZ continues west-northwestward from 07.5N22W
across 08N32W to 11N41W. Widely scattered moderate convection is
noted up to 80 nm along either side of the monsoon trough.
Scattered moderate convection is found up to 230 nm along either
side of the ITCZ.

The eastern end of the East Pacific monsoon trough is triggering
scattered showers and thunderstorms near Panama and northwestern
Colombia. Widely scattered showers and isolated thunderstorms are
found farther north across the southwestern Caribbean Basin.

...GULF OF MEXICO...

A surface trough is causing widely scattered showers and isolated
thunderstorms at the western Bay of Campeche. Otherwise, a broad
surface ridge extends southwestward from the Florida Big Bend area
to near Tampico, Mexico. Moderate to fresh ENE to E winds and seas
of 5 to 7 ft are noted for the eastern Gulf, including the Florida
Straits. Mainly moderate E to SE winds and seas at 4 to 6 ft
prevail for the rest of the Gulf.

For the forecast, the surface ridge will continue to support
moderate to fresh winds, locally strong in the eastern Gulf,
through the remainder of the week. Mainly gentle NE winds are
expected this weekend as the pressure gradient weakens and high
pressure settles over the region. The next cold front is forecast
to reach the northwestern Gulf on Mon. This front could bring
gale force winds.

...CARIBBEAN SEA...

Convergent easterly winds are taking advantage of divergent
upper- level winds south of an upper-level trough to produce
widely scattered to scattered moderate convection across the
central and eastern basin, including waters near the ABC Islands.
Refer to the Monsoon Trough/ITCZ section for additional convection
in the Caribbean Basin. Moderate to fresh with locally strong ENE
winds and seas of 5 to 7 ft are seen at the northwestern basin,
including the Gulf of Honduras. Moderate ENE to E winds and seas
of 4 to 6 ft exist at the north-central basin. Gentle to moderate
E to ESE winds and 2 to 4 ft seas prevail elsewhere in the
Caribbean Basin.

For the forecast, fresh to occasionally strong winds will prevail
in the northwestern and north-central Caribbean, including the
Windward Passage through the week. Gentle to moderate winds are
expected elsewhere.

...ATLANTIC OCEAN...

Please read the Special Features section at the beginning about
Storm to Hurricane Force winds associated with Post-Tropical
Cyclone Tammy southeast of Bermuda. In addition, near-gale winds
and very rough seas are persisting across the western Atlantic.

A cold front reaches southward from east of Tammy across 31N54W to
24N56W. Scattered moderate convection is occurring up to 80 nm
along either side of this feature. Farther south, convergent
southeasterly winds are generating scattered showers and isolated
thunderstorms near the Windward Islands. To the east, a surface
trough is causing similar conditions from 09N to 17N between 40W
and 51W. Refer to the Monsoon Trough/ITCZ section at the beginning
for additional convection in the Atlantic Basin.

Outside the areas mentioned in the Special Features section,
moderate to fresh SE winds and seas of 6 to 9 ft in moderate mixed
swells are seen north of 22N between 47W and 50W. To the east
north of 20N, gentle to moderate with locally fresh NNE to E
trades and 4 to 6 ft seas are evident between the northwest
Africa coast and 47W, including the Canary Islands. For the
tropical Atlantic from the Equator to 20N between 22W and the
Lesser Antilles, gentle to moderate with locally fresh NE to ESE
winds and seas at 4 to 6 ft exist, including the Cabo Verde
Islands. Light to gentle with locally moderate southeasterly and
monsoonal winds with 4 to 5 ft seas prevail for the remainder of
the Atlantic Basin.

For the forecast W of 55W, there is a possibility that Post-
Tropical Cyclone Tammy could regain tropical or subtropical
characteristics while it meanders over the northwestern Atlantic
through early next week. High winds and hazardous seas are still
present, and a Storm Warning is now in effect for portions of the
area southeast of Bermuda. Gales will continue into Fri. The
gradient between Tammy and high pressure near the Carolinas will
continue to support strong to near gale- fore NE winds and very
rough seas well west of Tammy across much of the area through the
week.

$$

Chan
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