[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162120
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Mar 17 2021

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2100 UTC.

...SPECIAL FEATURES...

Caribbean Sea Gale Warning: The pressure gradient from 1025 mb
high pressure well north of the area combined with 1008 mb low
pressure over northern Colombia will support gale-force winds
within 90 nm north-northwest of the Caribbean coast of Colombia
late tonight through early Wed. Seas are expected to build 8 to
12 ft, peaking around sunrise Wed. Another round of gale-force
winds is forecast for the same area Wed night, with similar
conditions possible again Thu night. Fresh to near gale-force
winds will persist elsewhere and otherwise in the south-central
Caribbean through the upcoming weekend.

Gulf of Mexico Gale Warning: A cold front is forecast to enter
the northwest Gulf of Mexico on Wed. Minimal gale-force winds
will occur across the Veracruz region in the wake of the front by
Thu. The gale-force winds will end by Wed night and the cold
front will exit the southeast Gulf on Fri. Seas will peak around
8-10 ft in and near the area of gale-force winds late Thu
afternoon and early Thu evening before subsiding as the winds
diminish.

Please read the latest NWS High Seas Forecast from the
National Hurricane Center at the website:
www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details on both
Gale Warnings.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea near 10N15W
to 03N24W. The ITCZ continues from 03N24W to 00N39W. Scattered
moderate and isolated strong convection is noted from 00N-06N
between 20W-29W. Scattered moderate convection is noted from
02N-07N between 07W-13W offshore of Sierra Leone and Liberia.

GULF OF MEXICO...

See the Special Features section above for more information on
the Gale Warning over the southwest Gulf of Mexico.

Weak surface ridging prevails across the Gulf of Mexico anchored
by 1025 mb high pressure in the Atlantic Ocean west-northwest of
Bermuda. Mainly moderate to locally fresh return SE-S flow was
noted by earlier scatterometer data. Available surface
observations indicate seas of mainly 3-5 ft across the basin,
locally to 6 ft in the central Gulf. Some isolated showers and
thunderstorms were noted in the northern Gulf in modest and moist
southwesterly flow aloft.

Fresh to locally strong southerly winds will develop over the
western and central Gulf by tonight into Wed ahead of the next
cold front forecast to reach the northwest Gulf of Wed. This
front will exit the southeast Gulf on Fri. Later in the weekend,
fresh to strong winds and building seas are expected in the NE
Gulf as a strong high pressure settles over the Carolinas.

CARIBBEAN SEA...

See the Special Features section above for more information on
the Gale Warning over the south-central Caribbean Sea.

Otherwise, the pressure gradient due to 1025 mb high pressure
well north of the area west-northwest of Bermuda and 1008 mb low
pressure over northern Colombia is supporting fresh to strong
winds south of Hispaniola, and across the approach and through
the Windward Passage. Mainly moderate to fresh trades prevail
elsewhere per earlier scatterometer data. Seas of 4-7 ft prevail
outside of the south-central Caribbean Sea, except 3-6 ft in the
northwest Caribbean. Scattered showers are occurring in the
eastern Caribbean Sea near the Leeward Antilles, as well as in
the southwest Caribbean and in the northwest Caribbean across
Nicaragua and Honduras and adjacent waters.

Fresh to strong winds are forecast to persist in the Windward
Passage tonight and south of Hispaniola tonight through Thu
night. Fresh to strong E-SE winds are expected in the Gulf of
Honduras tonight through Wed night. Mainly moderate to fresh
trades will dominate the remainder of the basin. A decaying cold
front is forecast to enter the far northwest Caribbean Fri night
with little fanfare.

ATLANTIC OCEAN...

An elongated cold front stretches from deep low pressure well
north of the area in the east-central Atlantic through 32N42W to
22N55W to 22N69W, with the tail of the front curving and
extending northwest as a dissipating stationary front to just
northeast of the central Bahamas near 26N76W. A pre-frontal
trough is noted within 120-240 nm southeast-south of the front.
Scattered showers are noted ahead of both features. Earlier gale-
force winds that were occurring north of 28N and west of the cold
front to 60W have diminished to fresh to strong, however very
large seas in fresh northerly swell continue to propagate through
the central Atlantic waters, up to around 25 ft near 31N55W per
earlier altimeter data. The outer edge of this large swell is
impacting the waters west of 65W where seas of 8-12 ft are found
north of the front between 65W-73W, with seas of 4-7 ft elsewhere
west of 65W and east of the Bahamas.

High pressure of 1025 mb is located west-northwest of Bermuda
near 33N70W. Mainly gentle winds are found north of the decaying
frontal boundary and west of 65W, except moderate to locally
fresh within about 120 nm north-northeast of the boundary.
Meanwhile a tight pressure gradient is noted offshore of the
Carolinas with 1017 mb low pressure noted near Cape Lookout,
North Carolina. This low is along a stationary front which
reaches southwest-west across Georgia and an area of fresh to
strong winds is north of 30N between 75W-80W.

The weakening frontal boundary will continue to wash out west of
65W tonight into early Wed. The large and long period northerly
swell behind the front, and associated with the deep low
pressure system well north of the area, will reach the Atlantic
passages east of La Mona passage by early Wed morning. The next
cold front is expected to push off the Florida coast on Thu
night. Fresh to strong southerly winds are expected ahead of this
front through Fri. By the weekend, strong winds and building
seas are expected to impact the coast of Florida as a strong high
pressure settles over the Carolinas.

$$
Lewitsky
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