[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sun Oct 22 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
1800 UTC.

...SPECIAL FEATURES...

Hurricane Tammy is centered near 19.1N 63.0W at 22/1500 UTC or
50 nm N of Anguilla, moving NW at 8 kt. Estimated minimum central
pressure is 992 mb. Maximum sustained wind speed is 70 kt with
gusts to 85 kt. Hurricane-force winds extend outward up to 20 nm
from the center and tropical-storm-force winds extend outward up
to 120 nm. Seas of 12 ft or greater extend out up to 180 nm,
especially N of the center where peak seas are near 25 ft.
Tammy is moving toward the northwest and this general motion is
expected today. A turn toward the north is expected tonight,
followed by a north-northeast or northeast motion on Tuesday.
Little change in strength is forecast during the next few days.
Numerous moderate to strong convection is noted within 60 nm of
center. Tammy is slowly pulling away from the northern Leeward
Islands. However, there is still a trailing area of showers and
thunderstorms that will likely cause heavy rain across portions of
the Windward and Leeward Islands throughout the day. These rains
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 National
Hurricane Center at web-site
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest
Hurricane Tammy Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

Southwestern Caribbean Sea (AL95): Showers and thunderstorms
have changed little in organization since this morning in
association with a low pressure system located over the
southwestern Caribbean Sea.  However, environmental conditions
are favorable for development, and a tropical depression could
form before the system moves inland over Nicaragua by early
Tuesday.  Regardless of development, this system could produce
heavy rains over portions of Central America during the next
couple of days. The latest Tropical Weather Outlook gives this
system a medium chance of tropical cyclone development through
48 hours, and also through 7 days. Refer to the latest NHC
Tropical Weather Outlook at www.hurricanes.gov for more details.

Gale Warning E of 35W: A 998 mb low pressure located over the
eastern Atlantic near 36N09W continues to support gale force
winds over the marine zones called Madeira and Agadir in the
Meteo-France High Seas Forecast area.

For more details, refer to the Meteo-France High Seas Forecast
listed on their website https://wwmiws.wmo.int

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal plains of southern
Senegal near 12.5N17W, and continues SW to near 11N25W. The ITCZ
extends from 11N22W to 08N35W to 11N49W. Scattered moderate to
isolated strong convection is from 06N to 10N between 25W and 35W.
Similar convective activity is noted from 09N to 11N between 48W
and 61W. The latter is just behind a surface trough that extends
from 15N50W to 07N54W.

...GULF OF MEXICO...

High pressure of 1017 mb centered over the NE Gulf near 28N85W
dominates most of the basin producing mainly light to gentle
anticyclonic flow and seas of 1 to 2 ft, with the exception of
gentle to moderate southerly return flow and seas of 2 to 4 ft W
of 94W. Narrow lines of low-level clouds are moving N over the
western Gulf under the influence of the southerly flow.

For the forecast, a cold front will skirt the far NE Gulf tonight.
High pressure will build toward the region from the north in the
wake of the front, leading to increasing E winds. Fresh to locally
strong winds and building seas are expected Mon into Thu.

...CARIBBEAN SEA...

Please read the SPECIAL FEATURES section for details about Hurricane
Tammy and Invest AL95.

A surface trough extends from the Cayman Islands to a 1008 mb low
pressure centered near 11N81.5W. Numerous showers, with embedded
thunderstorms are W of the through, more concentrated over the
Cayman Islands. An outer rain band of Hurricane Tammy continues
to impact the Lesser Antilles and the eastern Caribbean E of 65W.
Outside of Tammy, gentle to moderate N to NE winds are W of the
above mentioned trough, with light to gentle winds in the central
and eastern Caribbean. Seas are generally 3 to 5 ft over the
eastern Caribbean, and 2 to 4 ft elsewhere.

For the forecast, Hurricane Tammy will continue to move away from
the NE Caribbean. It will reach 20.1N 63.6W this evening, 21.4N
63.9W Mon morning, 22.3N 63.5W Mon evening, 23.0N 62.9W Tue
morning, 23.6N 62.0W Tue evening, and 24.5N 61.0W Wed morning.
Tammy will change little in intensity as it moves to near 27.5N
60.5W early Thu. A weak cold front will move into the northwest
Caribbean later today, then stall from eastern Cuba to near
Cozumel Island, Mexico Tue.

...ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for details about
Hurricane Tammy as well as gale conditions in the far eastern
Atlantic.

A cold front extends from 31N62W across the central Bahamas to
the coast of central Cuba near 22N78W. A band of showers with
isolated thunderstorms is related to the front. Gentle to moderate
winds follow the front with seas of 6 to 8 ft based on a recent
altimeter pass.

In the tropical Atlantic, a surface trough extends 15N50W to
07N54W. An area of fresh winds persists near the northern end of
the trough, particularly from 14N to 18N between 45W and 51W based
on scatterometer data. Seas of 7 to 9 ft are noted within these
winds. In the east Atlantic, a cold front extends from the coast
of Western Sahara near 23N16W to 22N30W to 28N43W. A band of
mainly low clouds and possible showers is associated with the
front. Moderate northerly winds are observed in the wake of the
front, increasing to fresh to strong between the Canary and the
Madeira Islands. Seas behind the front increase rapidly due to
swell generated from storm conditions to the north. Seas greater
than 12 ft are currently reaching the Canary Islands. Seas of 8
to 12 ft dominate most of the waters N of 23N and E of 34W.

For the forecast, Hurricane Tammy will move to 20.1N 63.6W this
evening, 21.4N 63.9W Mon morning, 22.3N 63.5W Mon evening, 23.0N
62.9W Tue morning, 23.6N 62.0W Tue evening, and 24.5N 61.0W Wed
morning. Tammy will change little in intensity as it moves to near
27.5N 60.5W early Thu. The aforementioned cold front will slide
east and gradually dissipate into tonight. A second cold front
will move off Florida tonight, then move eastward across the
northern portions of the waters early this week. Looking ahead,
high pressure building in the wake of the front combined with the
impacts of Hurricane Tammy will bring an increase in winds and
seas across the forecast area Mon night through Thu.

$$
GR
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