[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 142317
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Dec 14 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 1800 UTC surface analysis and satellite imagery through
2315 UTC.

...SPECIAL FEATURES...

Central Atlantic Gale Warning: A large and powerful low pressure
system centered north of the area near will bring strong to near
gale force W winds tonight through Thu night to the waters east of
65W and north of 27N. Very large seas can be expected in this
area. By Thu night, the forecast calls for W to NW winds of 30-35
kt N of 30N between 47W and 54W with seas of 17-23 ft in NW swell.
Please read the latest High Seas Forecast issued by the National
Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Sierra Leone near
09N13W to 07N17W. The ITCZ continues from 07N17W to 04N30W to
01N50W. Scattered moderate convection is noted north of the ITCZ
from 04N to 07N between 24W and 45W.

GULF OF MEXICO...

As of 2100 UTC, a cold front in the NW Gulf of Mexico extends
from central Louisiana to near Tampico, Mexico. A squall line of
thunderstorms precedes the front in the northern Gulf waters and
severe weather is possible in the coastal waters of SE Louisiana,
Mississippi, Alabama, and the Florida panhandle tonight. Gusts
will likely exceed 35 kts in the strongest thunderstorms. Recent
observations indicate strong NW winds behind the front, where seas
have built to 8 ft. Ahead of the front, fresh southerly winds and
5-7 ft seas prevail.

For the forecast, the cold front will reach from Apalachicola, FL
to the central Bay of Campeche early Thu and from near Sarasota,
FL to the central Bay of Campeche Thu night before slowing down
and beginning to weaken. A line of strong to severe thunderstorms
just ahead of the front will race eastward across the north-
central and NE Gulf tonight through Thu. Strong to near gale force
NW to N winds, with occasional gusts to 35 kt are presently west
of the front. These winds will diminish to fresh overnight into
Thu for the central and eastern Gulf. Fresh to strong southerly
winds ahead of the front will diminish Thu as the front approaches
Fl. The front should become stationary Fri night from the Straits
of Florida to the south-central Gulf of Mexico before weakening
further. The front should remain in about the same position
through Sat as a surface trough forms over the SW Gulf. The
gradient between this surface trough and high pressure over the
southern U.S. is likely to induce a large area of fresh to strong
N to NE winds over the central Gulf this weekend. Presently, it
appears that the trough will transition to a warm front on Sun and
lift northward to the NW Gulf by late Mon.

CARIBBEAN SEA...

Satellite derived wind data provide observations of fresh to
strong trade winds over the south-central Caribbean, near the
coast of Colombia. Fresh to locally strong winds are occurring
just S of Haiti, and in the Gulf of Honduras with mainly fresh E
winds in the Windward passage and downwind to near 77W. Moderate
to locally fresh winds prevail elsewhere. Seas are 6-8 ft in the
south-central Caribbean and 3-6 ft elsewhere, except up to 6-7 ft
in the NE Caribbean passages due to NE swell from the Atlantic.

For the forecast, high pressure over the western Atlantic will
maintain fresh to strong trade winds across the central Caribbean
Sea through Fri, with moderate to fresh winds elsewhere. Large
long-period N to NE swell will continue to propagate through the
NE Caribbean passages and affect the Tropical N Atlantic waters
for much of the week. Another large set of N swell is forecast to
begin propagating through the Tropical N Atlantic waters starting
late Fri and continue through Mon night.

ATLANTIC OCEAN...

See the Special Features section above for details on a Gale
Warning in the central Atlantic.

A cold front enters the forecast area near 31N48W and continues
SW to the SE Bahamas. Scattered showers and thunderstorms are
along the frontal boundary E of 57W. Fresh to locally strong SW
winds are N of 29N E of the front to about 45W based on
scatterometer data. Mainly gentle to moderate winds prevail
elsewhere on either side of the front. Seas of 8-11 ft in N-NE
swell follow the front especially E of 60W. High pressure, near
30N31W dominates the eastern Atlantic. A dissipating frontal
boundary is producing strong to near gale force SW-W winds and
rough or very rough seas near the coast of Morocco. Seas of 8-12
ft in NW swell are noted between the Madeira and the Canary
Islands.

An area of showers and thunderstorms is observed E of a surface
trough that extends from 20N56W to 13N58W. The convective
activity covers the waters from 17N-24N between 48W-54W. A
diffluent pattern aloft is helping to induce this convection.

For the forecast west of 55W, the cold front will weaken as it
shifts eastward through Thu in response to high pressure that
builds in behind it. Large long-period N to NE swell will continue
to affect much of the area for the next couple of days. A large
and powerful low pressure system north of the area will bring
strong to near gale force W winds tonight through Thu night to
the waters east of 65W and north of 27N. Very large seas can be
expected in this area. Farther west, fresh to strong southerly
winds will develop offshore NE Florida beginning tonight as a
strong cold front approaches the southeastern U.S. coast. The
front is forecast to move off the coast Thu afternoon, reach from
near 31N74W to West Palm Beach, Fl early Fri, and from near 31N65W
to the Florida Keys early Sat. Scattered to numerous showers and
thunderstorms are likely to move offshore the Florida coast on
Thu. On Sun, a reinforcing cold front is expected to merge with
it. The merged front is expected to reach from near 31N62W to the
central Bahamas and western Cuba Sun night and from near 29N55W to
26N66W and stationary to the central Bahamas by late Mon. The
fresh to strong southerly winds will shift eastward across the
northern and central waters through Sat and exit the area late
Sat. Fresh NW to N winds will follow behind the merged front.

$$
Flynn
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