[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152343
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sat Dec 16 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
2300 UTC.

...SPECIAL FEATURES...

Gulf of Mexico, Florida and Western Atlantic Gale Warning and
Significant Swell event: Strong high pressure of 1035 mb across
the eastern United States, extending eastward toward Bermuda
combined with a stationary front that stretches from 24N70W
across the NW Bahamas and the Straits of Florida into the Gulf of
Mexico supports gale force winds on either side of southern
Florida, including the Straits of Florida. A buoy in the central
Gulf of Mexico recently reported 17 ft while an altimeter pass
showed seas to 14 ft between Key West and Havana, Cuba. Another
altimeter pass indicated seas to 16 ft between Great Abaco and
Eleuthera in the NW Bahamas. Seas 12 ft of greater are noted
across the Gulf waters roughly from 23N to 27N between 84W and
92W. Similar sea heights are seen from 23N to 28N E of the
Bahamas to about 70W. A rapid deepening low pressure system in
the Gulf of Mexico will produce additional gales in the NE Gulf
and E of Florida beginning Sat. The strong low pressure is
forecast to move NE Sat and inland across the Florida Big Bend
and N Florida Sat night into Sun. This system will bring very
rainfall, gale force winds, coastal flooding due to onshore flow
and some threat for severe weather from Florida to the Mid-
Atlantic states. Gales will diminish in the eastern Gulf of
Mexico by Sun morning while persist E of Florida and N of the NW
Bahamas to about 74W. In that area, the forecast calls for S
winds of 30 to 45 kt and seas of 15 to 20 ft. A cold front
associated with this low will exit the Gulf of Mexico by Sun
morning. Gales will continue in the western Atlantic into early
next week.

Please read the latest NWS High Seas Forecast issued by the
National Hurricane Center at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough remains across the Africa continent. An ITCZ
extends westward from the Liberia coast near 06N10W to 06N30W to
03N49W. Scattered moderate convection is evident from 03N to 10N
between 10W and 20W, and from 03N to 06N between 20W and 31W.

...GULF OF MEXICO...

The big weather maker for this weekend in the Gulf of Mexico and
Florida is a rapid deepening low pressure system forecast to
bring severe weather conditions to the region. Please read the
Special Features section for more details. Gales and hazardous
marine conditions are ongoing in the basin.

For the forecast, strong high pressure building across the
eastern United States will support strong winds over the northern
and eastern Gulf of Mexico into tonight, with easterly gales
offshore Florida. Low pressure will form in the SW Gulf tonight,
then move NE Sat and inland across the Florida Big Bend Sat
night. This will produce additional gales in the NE Gulf beginning
Sat. Thunderstorms in association with this low will provide
locally even higher winds and seas Sat and Sat night. A cold
front will trail from the low, exiting the Gulf Sun morning.
Strong north winds will spill into the western and northern Gulf
Sat into Sun behind the front. High pressure will then settle in
over the area through early next week allowing for marine conditions
to improve.

...CARIBBEAN SEA...

Strong high pressure over the eastern of the United States and
the western Atlantic is producing fresh to strong NE to E winds
in the lee of Cuba to about 19N, and also in the lee of Hispaniola
to about 14N. Seas are in the 8 to 9 ft range within these winds,
reaching 10 ft in the Yucatan Channel. Seas of 8 to 9 ft are also
N of Jamaica. Moderate to fresh trades are noted over the south-
central Caribbean, including the Gulf of Venezuela. Elsewhere,
gentle to moderate winds prevail. Seas are generally 4 to 7 ft
in the rest of the basin. Some shower activity is over the NW
Caribbean on the south side of a stationary front located over
the SE Gulf of Mexico. Patches of low level moisture embedded in
the trade wind flow are observed elsewhere producing isolated to
scattered passing showers.

For the forecast, strong high pressure N of the region across
the eastern U.S. will support fresh to strong trade winds across
most of the basin into tonight, before the high pressure shifts E
and weakens, causing winds to gradually diminish into Sat night.
A cold front will move through the Yucatan Channel and into the
NW Caribbean Sat night, then stretch from the Windward Passage to
Costa Rica Mon. Fresh to strong NW to N winds will follow this
front.

...ATLANTIC OCEAN...

A Gale Warning is in effect E of south Florida. Please, see the
Special Features section for more information.

A cold front enters the forecast area near 31N50W, then continues
SW to near 25N68W where it becomes stationary crossing the Nw
Bahamas and the Straits of Florida. Strong to gale-force NE winds
are N of the stationary front to about 29N. Seas are 12 to 16 ft
in association with these winds just E of the Bahamas. These
winds are advecting abundant tropical moisture over Florida
producing intermittent locally heavy showers. As the low pressure
forecast to develop over the Gulf of Mexico approaches Florida,
showers will become widespread across South Florida and periods
of heavy rain will be possible especially heading into Saturday
afternoon and Saturday night. A second cold front extends from
31N37W to 21N41W. This front is attached to an occluded low
located N of area. The low pressure has weakened enough to allow
winds in its vicinity to drop below gale force, but it is still
generating an area of 12 to 14 ft over the waters N of 26N
between 36W and 40W. Seas are forecast to subside below 12 ft by
Sat morning. At this time, seas of 12 to 17 ft in NW swell are
expected in the wake of the aforementioned cold front, covering
the waters E of 55W and N of a line from 31N43W to 27N55W. The
remainder of the Atlantic is under the influence of ridge.

For the forecast, the above mentioned cold front will sink southward
before becoming fully stationary along 23N by Sat. The pressure
gradient between the strong high pressure north of the area and
the front will result in near gale to gale force northeast to
east winds and high seas over the waters W of 70W and north of
24N through this evening. The front will then gradually dissipate
Sat night through Sun, in advance of the Gulf of Mexico low
pressure system that will move NE across Florida Sat night. This
low will move through the NW Atlantic waters Sun, when a large
area of southerly gales will exist SE of the low. Thunderstorms
in association with this low will provide locally even higher
winds and seas this weekend.

$$
GR
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