[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162318
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sun Dec 17 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...

Gale Warning for Gulf of Mexico, Florida Offshore and Western
Atlantic: A stationary front extends westward from 24N58W to
25N80W, then continues as a warm front to a deepening 1008 mb low
at the central Gulf of Mexico near 26N89W. To the north, there
are two strong high pressures, a 1031 mb high over the U.S. Mid-
Atlantic States offshore waters and the 1029 mb Bermuda High.
Tight gradient between these features will maintain near-gale to
gale ENE to E winds along with 10 to 14 ft seas across the
central and eastern-central Gulf of Mexico, southeast Florida
offshore waters this evening. As the low at the central Gulf of
Mexico tracks northeastward toward the Florida Big Bend area and
deepens further tonight, these winds and seas will shift into the
northeastern Gulf of Mexico, and the offshore waters of
central/northeast Florida and northwest Bahamas. This low is
expected to cross northern Florida and southern Georgia early
Sunday morning and exit into the western Atlantic on by Sunday
afternoon. This will cause gale southerly winds and very rough
seas of 16 to 23 ft to shift northward and eastward into the
western Atlantic waters N of 26N and W of 75W. On the other hand,
this will allow winds and seas across the eastern Gulf of Mexico
and southeast Florida offshore waters to gradually subside.

Residual Large ENE Swell Event E of the Bahamas:
Decaying ENE swell will remain large enough to sustain 12 to 13 ft
seas from 22N to 27N between 69W and the Bahamas through this
evening. Afterward, the ENE swell will subside further and allow
seas to drop below 12 ft tonight. By Sunday afternoon, seas will
rise again as winds increase to between near-gale and gale-force
in respond to a deepening low pressure moving across norther
Florida and southern Georgia.

Gale Warning at the Central Atlantic:
A 1017 mb low pressure currently located near 29N52W will drift
southeastward today. Latest satellite scatterometer data continue
to show near-gale to gale-force NE winds just north and northeast
of the low from 28N to 31N between 49W and 51W. Earlier satellite
altimetery data also reveal seas of 12 to 15 ft in this area. As
the low shifts farther southeast this afternoon, the associated
pressure gradient will gradually weaken and winds are expected to
fall below gale-force by late afternoon. However, a broad area of
12 to 16 ft seas reinforce by increasing large NE swell will sink
southward and dominate the waters north of 25N between 49W and 58W
through tonight.

Please read the latest NWS High Seas and Offshore Waters
Forecasts issued by the National Hurricane Center at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and
https://www.nhc.noaa.gov/marine/offshores.php for more details of
these events.

...MONSOON TROUGH/ITCZ...

The monsoon trough remains over the Africa continent. The ITCZ
extends westward from just west of Sierra Leone at 07N14W to
07N47W. Scattered moderate convection is evident up to 100 nm
along either side of the ITCZ E of 24W.

...GULF OF MEXICO...

Please read the Special Features section above for details on the
Gale Warning in effect for the E Gulf waters.

Besides the deepening low and stationary front mentioned above, a
surface trough runs northward from the Yucatan Peninsula through
the low to the central Louisiana coast. Scattered showers and
thunderstorms prevail across the eastern half of the basin. To the
NW, a cold front is analyzed from 30N93W to 24N98W.

Outside the Gale Warning area, fresh to strong ENE to ESE winds
and seas of 8 to 12 ft dominate the north-central and eastern
Gulf, including the Florida Straits. Fresh to strong northerly
winds and 8 to 12 ft seas are present across the western Gulf,
including the western Bay of Campeche. Moderate to fresh NNE to SE
to SW winds with 7 to 11 ft seas in large NE swell prevail for
the rest of the Gulf.

For the forecast, the 1008 mb low pressure currently near 26N89W
will continue to strengthen as it moves ENE this evening and into
Florida near the Big Bend overnight. This will produce additional
gales in the NE Gulf tonight. Thunderstorms in association with
this low will provide locally higher winds and seas into Sun
morning over the eastern Gulf of Mexico. NW gales will present
behind the low Sun in the NE Gulf of Mexico. A cold front will
trail from the low, moving SE of the Gulf morning. Strong north
winds will continue behind this front in the northern and western
Gulf into Sun. High pressure will then settle in over the area
through early next week allowing for marine conditions to improve.

...CARIBBEAN SEA...

A surface trough runs southeastward from the Yucatan Channel to
the Gulf of Honduras. Convergent southeasterly winds east of the
trough axis are triggering scattered showers and thunderstorms
near western Cuba and the Cayman Islands. Otherwise, a 1029 mb
Bermuda High continues to channel trade winds across much of the
basin. Fresh with strong easterly winds and seas of 5 to 7 ft are
present SW of Hispaniola. Moderate to fresh E to ESE winds and 4
to 6 ft seas exist at the lee of Cuba and N of Colombia. Light to
gentle winds and 4 to 6 ft seas in moderate easterly swell are
evident at the Gulf of Honduras and southwestern basin. Moderate E
to SE winds and seas at 4 to 5 ft prevail elsewhere in the
Caribbean Sea.

For the forecast, strong high pressure N of the region across the
middle Atlantic states will support fresh to to locally strong
trade winds across the north-central basin tonight, before the
high pressure shifts E and weakens, causing winds to gradually
diminish Sun. A cold front will move through the Yucatan Channel
and into the NW Caribbean Sun, stretch from eastern Cuba to Costa
Rica Mon morning, then stall and weaken from central Hispaniola to
Panama by Wed. Fresh to strong NW to N winds will follow this
front, becoming N to NE on Wed.

...ATLANTIC OCEAN...

Please read the Special Features section about a ongoing Gale
Warning and significant swell event.

A cold front curves southwestward from a 1018 low near 29N49W to
well north of Puerto Rico at 24N59W, then continues westward as a
stationary front across the central Bahamas to beyond the Great
Bahama Bank. Scattered showers are noted W of 73W. To the E, a
surface trough extends from a 1014 mb low near 31N36W to 23N47W
with scattered showers.

Outside the Gale Warning and significant swell areas, fresh to
strong NE to E winds and seas of 8 to 11 ft are evident N of 18N
between 60W and the Florida east coast. Near the Canary and Cabo
Verde Islands, moderate to fresh NE to ENE trades and 4 to 7 ft
seas in moderate northerly swell are noted north of 06N between
the Africa coast and 30W. For the central Atlantic, light to
gentle winds and seas at 5 to 7 ft in moderate mixed swell are
found from 20N to 27N between 30W and 50W. For the tropical
Atlantic, gentle to moderate ENE to E winds and 5 to 7 ft seas
dominate from 05N to 20N between 30W and the Lesser Antilles.
Light to gentle southerly winds and 5 to 7 ft in mixed swell
prevail for the remainder of the Atlantic Basin.

For the forecast, the frontal boundary will weaken tonight and
dissipate by Sun. Strong to gale-force winds are noted N of this
boundary from 24N to 28N W of 75W, including the NW Bahamas and
offshore Florida. These winds will continue until the front
dissipates. A strengthening low pressure in the Gulf of Mexico
will move NE and into Florida tonight, then cross the far NW
waters Sun and move N of the area Sun night. Gales ahead of the
low will develop offshore Florida later tonight and Sun, then
spread E and NE with time, ahead of a cold front that will trail
this low. Behind the front, NW gales will also develop N of 28N by
Sun night. In the vicinity of the low and along the cold front
tonight through Sun night, strong thunderstorms will likely
produce locally much higher winds and seas. The cold front will
reach 30N75W to Central Cuba by Sun evening, then extend from
31N68W to Haiti by Mon night. The front will then stall into the
middle of next week.

$$
ERA
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