[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162024
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Fri Dec 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 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
2010 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic from the border of Guinea-
Bissau and Guinea near 11N15W to 09N18W. The ITCZ continues from
09N18W to 04N30W to 05N45W. Scattered moderate and isolated strong
convection is noted from 05N to 07N between 16W and 19W, and from
02N to 06N between 31W and 36W.

GULF OF MEXICO...

Two surface troughs are analyzed over the Gulf of Mexico, one
from the Florida Panhandle at 30N85W to 28N87W and the other from
26N86W to 22N89W. No significant convection is associated with
these features as high pressure ridging dominates the Gulf of
Mexico. Moderate SE winds dominate the Gulf basin, locally fresh
in the NW Gulf and also the SE Gulf through the Straits of
Florida. Seas are in the 2 to 3 ft range over the NE Gulf with
3 to 5 ft seas elsewhere, except locally 6 ft in the NW Gulf and
through the Straits of Florida.

For the forecast, high pressure will prevail across the northern
forecast waters through Sat, supporting moderate to locally fresh
winds. A cold front is forecast to enter the basin Sat night into
early Sun. Fresh to strong winds and building seas will prevail
west of the front.

CARIBBEAN SEA...

An area of scattered moderate and isolated strong convection is
observed on satellite imagery from 09N to around 17N between 77W
and 85W, including over portions of eastern Honduras and Nicaragua
where heavy rainfall is likely falling. Some additional convection
is noted over portions of Jamaica as well as Belize and northern
Guatemala aided by afternoon heating. The pressure gradient
between high pressure centered over the western Atlantic and lower
pressure over Colombia is supporting fresh to strong trade winds
over the central Caribbean, including the Windward Passage.
Moderate to fresh winds prevail elsewhere. Seas are in the 8 to 10
ft over the central Caribbean, 6 to 8 ft over the eastern
Caribbean, and 4 to 6 ft over the western Caribbean.

For the forecast, strong high pressure will prevail over the
western Atlantic through the forecast period. This will support
fresh to strong trade-winds over the central Caribbean through the
weekend. Moderate to fresh trades are expected elsewhere.

ATLANTIC OCEAN...

A surface trough is analyzed from 31N33W to 25N39W, which lies to
the east of a cold front that extends from 31N36W to 23N55W to
25N62W, then continues as a stationary front to 31N68W. High
pressure of 1034 mb is building in the wake of the front centered
north of the area near 35N59W. Earlier satellite derived winds
reveal this area of high pressure is supporting fresh to strong
winds behind the front between 35W and 67W. Another surface
trough producing some cloudiness with possible embedded showers is
analyzed from 31N74W to 27N75W. Moderate to fresh winds are noted
south of 27N and west of 67W. Gales north of the area have
generated a large northerly swell which has propagated into the
northern waters. The swell is producing seas of 12 ft or greater
north of 24N and behind the front to around 65W, and are currently
peaking near 19 ft over the discussion waters along 31N between
40W and 46W. Seas of 7 to 8 ft are found between 50W and 74W in a
mix of northerly swell. Elsewhere, gentle to moderate trade winds
are east of 40W, with moderate to fresh winds elsewhere west of
45W. Seas south of 20N and east of 50W are mainly 5 to 7 ft, while
north of 20N and east of 50W and ahead of the front are 4 to 6
ft.

For the forecast, high pressure north of the area is supporting
moderate to fresh winds over the forecast waters. The area of high
pressure will build southward, bringing an increase in winds and
seas.

$$
Lewitsky
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