[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301634
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 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 1200 UTC surface analysis and satellite imagery through
1630 UTC.

...SPECIAL FEATURES...

...Atlantic Gale Warning...

A cold front reaching from the eastern Azores to the central
Atlantic near 19N45W will stall and dissipate west of 30W through
the day today. A second, reinforcing cold front moving across the
north central Atlantic will move across the waters north of 25N
and east of 50W through tonight, accompanied by winds to minimal
gale force near 31N39W this afternoon. Very rough seas to 18 ft
will also accompany the front in NW swell, with swell to 8 ft
reaching south of 20N in the central Atlantic. Winds will
diminish through Fri as the front stalls along 27N. Seas to 12 ft
will linger through Fri north of 25N 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. Winds pulsing to minimal gale
force off Colombia are expected Thu night, with seas up to 11 ft.

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 on these events.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic from the coast of
Liberia near 05N09W to 06N17W. The ITCZ continues from 06N17W to
the equator at 44W near the coast of NE Brazil. A few showers and
thunderstorms are noted from the equator to 07N along the length
of the ITCZ.

...GULF OF MEXICO...

The gradient between a 1021 mb high pressure in the western
Atlantic and lower pressure over eastern Mexico is supporting
moderate SE to S flow across the majority of the Gulf. Seas are
predominately 3 to 5 ft across the basin.

For the forecast, 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 by Sat night/early Sun. Strong to
near gale force northerly winds will follow this front, with gale
conditions affecting the NW and SW basin on Sun and Sun night. 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 southern Caribbean.

A 1021 mb high pressure centered north of the area is supporting
fresh to strong trade winds across the central Caribbean. A recent
Altimeter pass indicated seas in the area are 7 to 9 ft. A
shearline is analyzed in the eastern Caribbean along 16N with
a fresh NE winds north of the feature and moderate NE winds to the
south. Seas in this area range from 4 to 6 ft. Elsewhere,
moderate E to SE winds and 3 to 5 ft seas are noted.

For the forecast, high pressure centered NE of the central
Bahamas is forecast to 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 tonight. On Mon, the tail of a cold front
will enter the far NW Caribbean supporting moderate to locally
fresh NE winds and building seas in the Yucatan channel.

...ATLANTIC OCEAN...

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

A 1021 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. Buoys are reporting moderate SW winds off
the northeast Florida coast, along with moderate E winds and 6 ft
seas south of 22N.

In the central Atlantic, a strong cold front has crossed 31N this
morning bringing a large area of increasing strong to near gale
force winds and 12-17 ft building seas from 29W to 51W and
north of 27N. 8 ft seas extend as far south as 17N in the central
Atlantic. Farther east, a weaker cold front extends from the
eastern Atlantic near 31N23W to 27N27W where it extends a stalled,
weakening boundary into the central Atlantic near 18N50W. A fresh
SW breeze extends 120 nm east of the boundary with isolated
thunderstorms north of 28N. The subtropical ridge extends SW from
high pressure over the Iberian Peninsula to 17N40W. Gentle to
moderate NE winds and 5 to 7 ft seas are observed south of the
ridge, increasing to moderate to fresh and 7 to 9 ft seas west of
35W and south of 14N.

For the forecast west of 65W, the high pressure centered NE of
the central Bahamas will remain nearly-stationary through Sun. The
high pressure will weaken and move east Sun evening ahead of a
strong cold front moving off the northeast Florida coast late Sun
night. Fresh to strong southerly winds are forecast to the N of
the Bahamas ahead of the front Sat night, increasing to near gale
force speeds Sun and continuing through Mon morning. Building seas
associated with the front will subside to the east of the Bahamas
by mid-week.

$$
FLYNN
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