[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291659
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Wed Dec 29 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
1645 UTC.

...SPECIAL FEATURES...

...Atlantic Gale Warning...

A cold front reaching from the eastern Azores to the central
Atlantic near 20N45W will stall and dissipate west of 35W through
tonight. 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 31N35W 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 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.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends through west Africa to the coastal
boarder of Liberia near 06N11W. The ITCZ continues from 06N11W to
02N49W near the coast of NE Brazil. Scattered moderate convection
with embedded thunderstorms is noted from 02N to 06N 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 generating moderate to fresh
SE to S winds across the majority of the Gulf. Seas are
predominately 5 to 7 ft with up to 8 ft likely in the central
basin.

For the forecast, A ridge extending from the western Atlantic
into the Gulf will support moderate to fresh winds across the
central and western Gulf through Wed night. The ridge will shift
eastward, allowing for gentle to moderate winds and slight to
moderate seas across the entire basin Thu as a weak frontal
boundary stalls and dissipates along the Texas coast. Southeast to
south winds are expected to increase over the western Gulf by
late Fri as low pressure moves into the Central Plains. A strong
cold front associated with this low pressure may reach the Texas
coast late Sat night or early Sun before it quickly moves to the
eastern Gulf late Sun. Gale-force winds are possible behind the
front over the western Gulf from early Sun through Mon night, with
strong to near gale-force winds elsewhere across the area in the
wake of the front. Seas are expected to quickly build behind the
front as well.

...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 across the central Caribbean and Gulf
of Honduras, with 5 to 7 ft seas, possibly reaching 9 ft off
Colombia where a recent scatterometer satellite pass indicated
near gale force NE winds. Elsewhere, moderate E to SE winds and 3
to 5 ft seas are observed. No significant shower or thunderstorm
activity is evident at this time with waver vapor satellite
imagery confirming very dry air dominates the basin.

For the forecast, the high pressure will strengthen through Thu,
supporting moderate to fresh trade winds across the Caribbean
through Sun, except for the NW, south-central and portions of the
SW basin where locally strong winds are expected. Gale force
winds are expected off Colombia Thu 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 NE of the Bahamas near 27N67W dominates
the weather in the Western Atlantic generating light to gentle
anticyclonic flow and 3 to 5 ft seas west of 65W except for
moderate SW winds off northeast Florida and moderate E winds
extending 180nm north of the Greater Antilles. Farther east, a
cold front extends from 31N30W to 20N46W in the central Atlantic.
Scatterometer data confirms a fresh westerly breeze behind the
front with strong SW winds extending 300 nm ahead of the front
north of 24N. Scattered moderate convection is observed east of
the front within 120 nm. Near gale force winds expected in the
vicinity of thunderstorms. Significant wave heights of 12-15 ft
area noted from 26N to 31N between 30W and 55W 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 20N35W. Gentle to moderate NE winds and 5 to 7 ft
seas are observed south of the ridge.

For the forecast west of 65W, a shear line, remnants of a cold
front will move east of the southeast region today. High pressure
currently NE of the central Bahamas will strengthen through Sat.
The high pressure will weaken and move east Sun ahead of a strong
cold front moving off the northeast Florida coast late Sun night.

$$
FLYNN
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