[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201023
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Fri Oct 20 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
1000 UTC.

...SPECIAL FEATURES...

Tropical Storm Tammy is centered near 14.0N 58.3W at 20/0900 UTC
or 90 nm NE of Barbados, moving WNW at 7 kt. Estimated minimum
central pressure is 1000 mb. Maximum sustained wind speed is 50
kt with gusts to 60 kt. Peak seas are currently around 22 ft.
Tammy has numerous moderate to isolated strong convection
observed from 07N to 16N and between 55W and 59W. A gradual turn
to the northwest with a decrease in forward speed is forecast
later today. A more northward motion is forecast to begin Saturday
night or Sunday. On the forecast track, the center of Tammy will
move near or over the Leeward Islands this evening through
Saturday, and then move north of the Leeward Islands Sunday.
Gradual strengthening is expected to begin later today and
continue into this weekend. Tammy is forecast to be at or near
hurricane intensity when it moves near the Leeward Islands
Saturday. Heavy rains from Tammy will begin to affect the Leeward
and northern Windward Islands later this morning, spreading into
the British and U.S. Virgin Islands and Puerto Rico over the
weekend. This rainfall may produce isolated flash and urban
flooding, along with isolated mudslides in areas of higher
terrain. Swells generated by Tammy will continue to affect
portions of the Lesser Antilles during the next few days. These
swells are likely to cause life- threatening surf and rip current
conditions. Please consult products from your local weather
office. 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 Tammy
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough reaches the Atlantic through the coast of
Guinea-Bissau near 12N16W and continues to 14N27W and then to
00N42W. Scattered moderate convection is observed from 03N to 14N
and east of 37W.

...GULF OF MEXICO...

A weak surface trough extends from 28N92W to 19N94W and is void of
significant convection. The rest of the basin is under a weak
high pressure pattern and a dry airmass that suppresses the
development of showers and thunderstorms. Moderate or weaker winds
prevail across the Gulf, with seas of 3-4 ft are found in the SE
Gulf and 1-3 ft elsewhere.

For the forecast, high pressure from the northern Gulf coast into
South Carolina will shift SW through Sat, allowing a cold front
to sag into the NE Gulf. This front will weaken through the
eastern Gulf through the weekend, before moving E of the area.
Looking ahead, high pressure building in the wake of the front
will support moderate to fresh E winds Sun night through Tue.

...CARIBBEAN SEA...

Please see the Special Features section above for more details on
Tropical Storm Tammy located just east of the Lesser Antilles.

A surface trough extends from western Cuba to Belize and is
producing scattered moderate convection within 90 nm of its axis.
Meanwhile, the eastern Pacific monsoon trough enters the SW
Caribbean Sea near 11N83W and continues eastward to northern
Colombia near 11N75W. Scattered moderate to isolated strong
convection is evident on satellite imagery south of 13N. No deep
convection is present elsewhere in the Caribbean.

Moderate to locally fresh easterly trade winds and seas of 3 to 5
ft are found in the south-central Caribbean. Outside of the
influence of Tammy, moderate or weaker winds and 2 to 4 ft seas
are prevalent in the rest of the basin.

For the forecast, Tropical Storm Tammy is near 14.0N 58.3W at 5
AM EDT, and is moving west-northwest at 7 kt. Maximum sustained
winds are 50 kt with gusts to 60 kt, and the minimum central
pressure is 1000 mb. Tammy will move to 14.7N 59.4W this
afternoon, 15.9N 60.7W Sat morning, then strengthen to a hurricane
near 17.3N 61.8W Sat afternoon. Hurricane Tammy will be near
18.8N 62.6W Sun morning, 20.3N 63.2W Sun afternoon, and 21.7N
63.4W Mon morning. Tammy will change little in intensity as it
moves N of the Leeward Islands early Tue. Elsewhere, a trough will
persist over the northwest Caribbean into Sat. Looking ahead, a
weak cold front will move into the northwest Caribbean by Mon then
stall through Tue.

...ATLANTIC OCEAN...

Please see the Special Features section above for more details on
Tropical Storm Tammy located just east of the Lesser Antilles.

A surface trough enters the tropical Atlantic near 31N57W and
continues southwestward to 27N69W. Farther west, another surface
trough stretches from 31N75W to 23N75W. These two features
combined with divergent flow aloft is resulting in a broad area of
scattered moderate convection N of 25N and W of 60W.

The subtropical ridge centered near 32N36W is the main feature of
interest in the central and eastern Atlantic outside of the deep
tropics. The pressure gradient between this high pressure and
Tammy sustain fresh to locally strong E-SE winds from 20N to 27N
and between 53W and 67W. Seas in these waters are 6-10 ft. A cold
front extends from Morocco to 27N36W and is producing no
convection. N of the boundary, moderate to locally fresh N winds
and seas of 6 to 10 ft area present. Across the remainder of the
basin, winds are mainly moderate with seas of 4 to 7 ft.

For the forecast W of 55W, Tropical Storm Tammy is near 14.0N
58.3W at 5 AM EDT, and is moving west-northwest at 7 kt. Maximum
sustained winds are 50 kt with gusts to 60 kt, and the minimum
central pressure is 1000 mb. Tammy will move to 14.7N 59.4W this
afternoon, 15.9N 60.7W Sat morning, then strengthen to a hurricane
near 17.3N 61.8W Sat afternoon. Hurricane Tammy will be near
18.8N 62.6W Sun morning, 20.3N 63.2W Sun afternoon, and 21.7N
63.4W Mon morning. Tammy will change little in intensity as it
moves N of the Leeward Islands early Tue. Elsewhere, a surface
trough from 31N58W to eastern Cuba will weaken today before
dissipating. A cold front will move off the SE U.S. Friday night
then cross northern waters through the weekend. Fresh to locally
strong winds will develop on both sides of the front.

$$
KONARIK
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