[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Mon Dec 20 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...

Gulf of Mexico Gale Warning: A strengthening low pressure is over
the W central Gulf near 23N93W. It will sustain near-gale to gale
force winds and seas at 11 to 14 ft off the Mexico coast, NE of
Tampico and S of Matamoros through this afternoon. As the low
tracks northeastward this evening and Tue morning, it will shift
near-gale winds and seas of 8 to 10 ft into the N central Gulf.
Please refer to the latest High Seas Forecast issued by the
National Hurricane Center, at the following website:
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details.

Atlantic Gale Warning: The aforementioned low pressure in the Gulf
of Mexico will move northeastward across northern Florida Tue,
and into the Atlantic Tue evening. This strengthening low will
cause gale force southerly winds from late Tue evening into Wed
morning, mainly N of 28N and W of 72W. Seas of 10 to 13 ft are
also likely in the area of gale force winds. As the low moves well
NE of the area and in the wake of the cold front, conditions will
slowly improve by Wed night. Please refer to the latest High Seas
Forecast issued by the National Hurricane Center, at the following
website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more
details.

Eastern Atlantic Gale Warning from 35W eastward: Gale-force winds
are forecast in the zone named IRVING, W of Madeira. An Azores
low pressure center and two frontal boundaries are to the north of
25N from 31W eastward. These conditions are expected to continue
until 21 December at 21 UTC. Please refer to the Meteo-France High
Seas Forecast on the following website,
http://www.gmdss.org/bulletins/METAREA2.HIGH_SEAS_WARNING.1956.19
1956225601.html, for more details.

...MONSOON TROUGH/ITCZ...

An ITCZ extends westward from SW of Liberia at 04N10W to 03N32W,
then continues west-northwestward from 04N36W to near the Guyana
coast. Scattered moderate to isolated strong convection is flaring
up near the first ITCZ from 02N to 07N between 15W and 32W.
Scattered showers are seen near the second ITCZ from 02N to 07N
between 35W and 43W, and from 06N to 12N between 46W and 58W.

The E Pacific monsoon trough is triggering scattered showers and
isolated thunderstorms near Panama and nearby Caribbean waters.

...GULF OF MEXICO...

Please see Special Features section above for details on near-gale
to gale conditions in the Gulf through Tue morning.

A stationary front extends eastward from a 1012 mb low over the W
central Gulf at 23N93W to NW of Cuba at 23N85W, then continues as
a weakening cold front through the Straits of Florida. Scattered
showers and thunderstorms are flaring up near the low and across
the N central Gulf. Another cold front curves southwestward from
this same low through the Bay of Campeche into S Mexico. Scattered
showers are found over the Bay of Campeche.

Outside the influence of the gale winds, fresh to strong ENE to SE
winds and seas of 7 to 9 ft are present over the N and central
Gulf. Similar conditions with NW winds are noted for the Bay of
Campeche. Moderate to locally fresh ENE to ESE winds and seas at 4
to 7 ft prevail for the rest of the Gulf.

For the forecast, the stationary/cold front that extends from
the low to the Straits of Florida is beginning to stall early
this morning, and should retreat northward as a warm front Tue.
Meanwhile the second cold front over the Bay of Campeche will
continues to move E through Tue as the low tracks NE toward N
Florida. Gales offshore Veracruz early this morning will
propagate NE through the day, to the N and W of the center of the
low, and into the N central Gulf of Mexico. The low and cold
front will move E and through the basin by later on Tue, with
strong winds and high seas impacting most of the basin, before
conditions improve Wed, as weak high pressure builds into the
area.

...CARIBBEAN SEA...

Refer to the Monsoon Trough/ITCZ section for weather in the
Carribbean Basin. Gentle to moderate easterly trade winds and
seas of 5 to 8 ft are evident across the central and E Caribbean
Sea. Mainly gentle easterly trades with seas at 3 to 5 ft prevail
for the NW Gulf.

For the forecast, as the Bermuda High remains weak and centered
well NE of the Caribbean, the trade winds will only reach
moderate to fresh over the S central Caribbean and gentle to
moderate elsewhere for the next several days. A cold front will
move through the Yucatan Channel Tue, then reach from E Cuba to
Nicaragua by Thu morning, before stalling. Fresh N winds can be
expected behind this front. Large N to NE swell will continue in
the tropical N Atlantic into Tue.

...ATLANTIC OCEAN...

Please see Special Features section above for gale and high sea
conditions that will develop offshore from N Florida on Tue and
ongoing in the far eastern Atlantic S of the Azores.

A cold front extends northeastward from the NW Bahamas to beyond
NE of Bermuda. Scattered showers and thunderstorms are occurring
near the front N of 27N between 65W and 79W. Strong mid to upper-
level winds are spreading lots of high clouds over the E tropical
Atlantic, including the Cabo Verde Islands. The southwestern end
of a second weakening cold front is generating scattered showers
and thunderstorms near the Canary Islands.

A large dome of 1020 mb high centered near 27N47W is dominating
the central Atlantic Basin with light to gentle winds and seas of
4 to 6 ft N of 22N between 40W and 65W. Farther E, Gentle to
moderate with locally fresh SW to WNW winds and seas of 9 to 12 ft
are found N of 25N between the NW African coast and 34W. Mostly
moderate to fresh NE to ENE trades and seas of 8 to 10 ft are seen
from 02N to 20N between the central African coast the Lesser
Antilles. Gentle to moderate SE to SW winds and seas of 5 to 7 ft
prevail for the remainder of the basin.

For the forecast W of 65W, the cold front from west of Bermuda
through the NW Bahamas to the Florida Straits will track east
today, with little additional southward progress. Strong E winds
will occur N of 29N in association with it today. Low pressure
developing in the Gulf of Mexico and moving northeastward to
offshore NE Florida and Georgia today into Tue will cause the W
portions of the front to retreat northward as a warm front. Near
the low, strong to gale force winds are expected over N waters Tue
into Wed night. Building high pressure behind the low should lead
toward tranquil conditions on Thu and Fri.

$$

Chan
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