[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 300438
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Thu Dec 30 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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0430 UTC.

...SPECIAL FEATURES...

...Atlantic Gale Warning...

A cold front reaching from the eastern Azores to the central
Atlantic near 20N47W will stall and dissipate west of 35W through
early Thu morning. A second, reinforcing cold front moving
across the north central Atlantic will move across the waters
north of 25N and east of 50W through Thu night, accompanied by
winds to minimal gale force near 31N39W Thu afternoon. Very rough
seas to 18 ft will also accompany the front in NW swell, with
swell to 8 ft reaching as far south as 22N east of 55W through Thu
night. Winds will diminish through Fri as the front stalls along
27N. Seas to 12 ft will linger through Fri north of 22N between
35W and 55W.

...Caribbean Gale Warning...

High pressure centered northeast of the Bahamas will build
through Fri, supporting fresh to strong trade winds across the
central Caribbean Sea through Sun, with winds pulsing to minimal
gale force off Colombia Thu night, with seas to 14 ft. Gale force
winds are expected to pulse once again on Fri night.

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

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic from the coast of
Sierra-Leone near 08N13W to 07N16W. The ITCZ continues from
07N16W to 03N30W to 01N47W near the coast of NE Brazil. Scattered
moderate convection is noted from 01N to 05N along the length of
the ITCZ.

...GULF OF MEXICO...

The gradient between high pressure in the western Atlantic and
lower pressure over eastern Mexico is supporting moderate to
locally fresh SE to S winds across the majority of the Gulf.
Seas are predominately 5 to 7 ft across the basin, with the
exception of 2-4 ft seas in the SE Gulf.

For the forecast, the surface high pressure centered NE of the
central Bahamas will remain nearly stationary through Sun and
support moderate to locally fresh return flow across the central
and western basin, increasing to fresh to strong Fri night as the
pressure gradient increases ahead of a strong cold front forecast
to come off the coast of Texas Sat evening. Strong to near gale
force northerly winds will follow this front, with gale conditions
affecting the NW and SW basin on Sun/Mon. The front is forecast
to move east of the gulf Mon morning. Winds and seas associated
with the front will gradually subside through Mon night.

...CARIBBEAN SEA...

Please see the Special Features section for details about the
gale warning in effect for the Caribbean.

A 1022 mb high pressure centered north of the area is supporting
fresh to strong trade winds with seas of 5 to 8 ft across the
central Caribbean. Fresh NE to E winds are noted across the
eastern part of the basin, including the Anegada passage where a
shear line is analyzed. Seas in this area range from 4 to 6 ft.
Elsewhere, moderate E to SE winds and 3 to 5 ft seas are
observed. Water vapor satellite imagery reveals a very dry
airmass stretching across the basin, thus, no significant shower
or thunderstorm activity is evident at this time.

For the forecast, the high pressure centered NE of the central
Bahamas will remain nearly-stationary through Sun, supporting
moderate to fresh trade winds across the Caribbean, except for
locally strong winds in the Gulf of Honduras, central Caribbean
and portions of the SW basin. Gale force winds are expected off
Colombia Thu night and Fri night.

...ATLANTIC OCEAN...

Please see the Special Features section for details about the
gale warning in effect for the Atlantic.

A 1022 mb high pressure located northeast of the central Bahamas
near 26N67W dominates the weather over the western Atlantic.
This is generating mostly light to gentle anticyclonic flow and
3 to 5 ft seas west of 65W. Moderate SW winds are observed off
the northeast Florida coast in a recent scatterometer pass,
along with moderate E winds south of 22N.

Farther east, a surface trough is analyzed from 31N43W to 28N46W
along with a cold front that extends from 31N26W to 20N47W in
the central and eastern Atlantic. A scatterometer pass this
evening reveals strong winds within 140 nm of either side of the
trough axis. Satellite derived winds also observe fresh westerly
winds behind the cold front with strong SW winds extending 300 nm
ahead of the front north of 24N. Scattered moderate convection is
observed within 300 nm east of the front north of 24N. Significant
wave heights of 12-14 ft area noted from 26N to 31N between 30W
and 50W with 8 ft seas extending as far south as 17N in the
central Atlantic. The subtropical ridge extends from high pressure
over the Iberian Peninsula to 28N20W. Gentle to moderate NE winds
and 5 to 7 ft seas are observed south of the ridge.

For the forecast west of 65W, the high pressure centered NE of
the central Bahamas will remain nearly-stationary through early
Sun. The high pressure will weaken and move east Sun ahead of a
strong cold front moving off the northeast Florida coast late Sun
night. Strong to near gale force winds and building seas
associated with the front will affect the offshore waters N of 26N
Sun and Mon.

$$

Nepaul
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