[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 210917
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Wed Dec 21 2022

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
0850 UTC.

...SPECIAL FEATURES...

Gulf of Mexico Gale Warning: A 1016 mb low pressure area is
centered near 27.5N86W. A cold front extends from the low through
23.5N90W to 18N94W. A stationary front extends from the low to
across Central Florida. A tight pressure gradient extends north of
the low and stationary front. Frequent gusts to gale force are
still occurring in the coastal waters of Florida between 85W and
86.5W where seas are 7-10 ft. Frequent gusts to gale force are in
the process of diminishing.

SW N Atlantic Gale Warnings: A 1018 mb low pressure area is east
of Jacksonville, Florida near 30N80W which developed along a
persistent sharp trough. Sustained winds are currently 20-30 kt
north of 29N and west of 76W, with frequent gusts to 35 kt north
of 30.5N within 60 nm of shore. Sustained gale-force NE-E winds
will develop north of 30N and west of 77W shortly after sunrise as
the pressure gradient tightens with seas building to 8-12 ft. The
low is forecast to become elongated by the afternoon with gale-
force winds diminishing.

Meanwhile, a surface trough is analyzed from 27N76.5W to
23.5N80.5W. A shearline is analyzed east of the trough across the
Central Bahamas to 23N65W. Fresh to strong E-SE winds and 7-9 ft
seas are occurring north of the shearline to 27N. Low pressure is
forecast to develop along the trough near 30N79W later this
morning with winds from 26N-28N increasing to 25-35 kt with seas
building to 8-10 ft. The low is forecast to shift east through the
afternoon and evening while gradually becoming broad. Gales will
shift east with the low all the way to 68W late tonight before
diminishing by early Thu. Seas will peak at 10-12 ft in the gale-
force winds tonight.

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

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic through the coast of
Sierra Leone near 08.5N13W and continues to 06N20W. The ITCZ then
extends from 06N20W to 02N35W to near the coast of Brazil at 02N51W.
Showers with a few isolated thunderstorms are observed on
satellite imagery south of 07N between 10W and 52W.

GULF OF MEXICO...

Please read the Special Features section above for information
on a diminishing frequent gust Gale Warning in the Florida coastal
waters between 85W and 86.5W.

As mentioned above, a 1016 mb low pressure area is centered near
27.5N86W. A cold front extends from the low through 23.5N90W to
18N94W. A stationary front extends from the low to across Central
Florida. Fresh to strong N-NE winds and 7-10 ft seas are noted
elsewhere west of the cold front, dimishing to 15-20 kt in the
central portion. Fresh to strong NW-N winds are offshore Veracruz
to 94W with seas of 8-12 ft. Convection that was present in the
east-central and SE Gulf has mainly diminished over the past few
hours. Gentle to moderate mainly southerly winds are southeast of
the cold front, along with 2-5 ft seas.

For the forecast, the front will completely stall and become
diffuse while the low drifts S while dissipating through today.
Winds elsewhere west of the front will gradually diminish today.
A stronger cold front is expected to move off the Texas coast Thu
evening followed by near-gale to gale force NW winds and rough to
very rough seas across most of the basin through Fri, lingering
through Fri night off Veracruz where minimal storm-force winds
will be possible Fri afternoon. Occasional storm force gusts
cannot be ruled out elsewhere in the western and central Gulf late
Thu night through Fri. Conditions will slowly improve through the
upcoming weekend.


CARIBBEAN SEA...

High pressure over the eastern United States extends southward
into the Caribbean Sea, maintaining fairly tranquil weather
conditions, except for a few pockets of shallow moisture moving
through the NW Caribbean as well as the eastern Caribbean. The
pressure gradient between the ridge to the north and lower
pressures in northern South America sustain mainly fresh to strong
easterly trade winds in the central Caribbean south of 20N, with
the strongest winds occurring off NW Colombia and in the Gulf of
Venezuela. The seas in these waters are 5-8 ft. Moderate to
locally fresh easterly breezes and seas of 3-6 ft are present in
the eastern Caribbean. Elsewhere, light to locally moderate
easterly winds and slight seas prevail, locally fresh through the
Windward Passage.

For the forecast, surface ridging north of the region combined
with low pressure over Colombia will continue to support pulsing
fresh to strong NE to E tradewinds across the central and SW
Caribbean through the remainder of the week and upcoming weekend.
Moderate to fresh winds will prevail in the E Caribbean with
gentle to moderate winds in the W Caribbean. Moderate, long-
period N to NE swell will continue to move into the tropical
Atlantic waters for the next several days. A cold front will move
into the Yucatan Channel by late Fri and reach from central Cuba
to Belize by Sat night, dissipating from eastern Cuba to eastern
Honduras Sun. Fresh to locally strong winds and rough seas will
follow the front.

ATLANTIC OCEAN...

Please read the Special Features section for details on two Gale
Warning areas in the SW N Atlantic.

Elsewhere in the SW N Atlantic, a ridge extends from near the
Outer Banks of North Carolina through 31N70W to 27N60W with
moderate to locally fresh anticyclonic winds and 5-7 ft seas. A
stationary front extends from 31N46W to 26N55W to 23N65W. Moderate
to fresh winds are noted on either side of the front north of 30N
between 45W-55W. Seas of 8-12 ft in associated NW-N swell covers
the waters north of 28N between 35W-60W.

Southeast of the front, ridging dominates from near the Canary
Islands through 30N30W to 24N55W. Mainly gentle winds and 6-8 ft
seas in NE swell prevail within roughly 180 nm either side of the
ridge axis. Moderate to fresh trades prevail elsewhere south of
the ridge across the deep tropical Atlantic, with seas of 6-9 ft,
highest west of the Cabo Verde Islands.

For the forecast west of 55W, both lows referenced in the Special
Features section will dissipate by early Thu with gales
diminishing by then. Winds will become southerly Thu ahead of a
strong cold front expected to move off the northeast Florida coast
Fri, accompanied by strong to near-gale force NW winds and rough
seas. NW gales are possible to the east of northern Florida with
this front.

$$
Lewitsky
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