[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271738
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sat Nov 27 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
1700 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the Guinea and Sierra Leone
coastlines near 09N13W to 09N14W. The ITCZ continues from 09N14W
to 04N31W to 03N51W. Scattered moderate convection is noted from
01N to 08N between 20W and 42W.

GULF OF MEXICO...

A cold front from the Atlantic extends across the Florida Straits
to the southwest Gulf near 24N85W and continues as a stationary
front to near Veracruz, Mexico. Fresh to locally strong NW to N
winds and 5 to 8 ft seas are ongoing over the far western Gulf,
west of 95W and along the Mexican coast. Moderate N to NE winds
and 3 to 5 ft seas are noted north of the front, with light to
gentle N winds and slight seas south of the front. Clouds with
embedded showers are increasing over the northwestern Gulf, where
a surface trough is analyzed from 29N96W to 26N94W.

For the forecast, a low pressure will develop off northeast
Mexico tonight, lifting the western portion of the aforementioned
front northward. The low and front will move into the south-
central Gulf by Sun night, then dissipate along with the front
Mon, ahead of a stronger front moving into the northern Gulf Sun.
Looking ahead, the second front will move through the Florida
Straits late Mon and Tue, then stall over the Yucatan Channel Wed.

CARIBBEAN SEA...

A surface trough extends over the northeast Caribbean across the
Anegada Passage from 20N63W to 15N65W producing low clouds with
embedded showers. Scattered showers and isolated thunderstorms are
active off Panama south of 11N, otherwise, no significant
convection is noted elsewhere. Seas to 9 ft were observed over the
Atlantic waters east of the Leeward Islands by a recent altimeter
pass. This is due to continued northerly swell moving into the
region. Seas of 5 to 6 ft are across the Atlantic Passages in the
northeast Caribbean with 3 to 5 ft elsewhere, except in the Lee
of Cuba, far eastern Caribbean, and Atlantic Coast of Nicaragua
and Costa Rica, where 1 to 2 ft can be found.

For the forecast, moderate to fresh NE to E winds will persist
over mainly the central Caribbean into the middle of next week.
Moderate N swell will continue across the Atlantic waters east of
the Leeward Islands and into Atlantic passages in the northeast
Caribbean through late Sun. Looking ahead, a weak cold front will
move into the northwest Caribbean late Tue, then stall and
dissipate through Wed.

ATLANTIC OCEAN...

A cold front extends from 31N67W through the northern Bahamas
into the southeastern Gulf of Mexico. Moderate NW winds are
evident in recent scatterometer data behind the front mainly north
27N. Ahead of the front, scatterometer data also indicated mostly
fresh southerly winds north of 30N to near 60W. Buoy and
altimeter satellite data showed 7 to 9 ft seas north of 28N,
likely in a mix of NE and NW swell. Light to gentle winds and 5 to
7 ft seas in NE swell are noted elsewhere over open waters west
of 65W. Farther east, scatterometer data indicate the wind shift
associated with a weakening stationary front over the central
Atlantic that extends from 31N47W to 20N56W. Seas of 8 to 12 ft
seas in N swell are observed over much of the area north of 22N
between 35W and 60W, with gentle to moderate winds elsewhere.
Based on scatterometer data, a shearline is analyzed south of the
Canary Islands extending westward from the Western Sahara to near
25N30W. A strong high pressure follows this feature. Also, fresh
to strong NE winds and seas of 8 to 13 ft in N to NE swells are
noted behind the shearline.

The Cumbre Vieja volcano, on the island of La Palma in the Canary
Islands, has been erupting since 19 September 2021. Low to medium
ash concentration is possible near the volcano and is drifting
southwestward to the west of Hierro Island. Marine and aviation
interests should monitor this ongoing situation by reading the
Volcanic Ash Advisory issued by Meteo- France, at
http://vaac.meteo.fr/volcanoes/la- palma/.

For the forecast west of 65W, the cold front from 31N67W through
the NW Bahamas to the Florida Keys will reach from Bermuda to the
Florida Keys later today, then then stall and dissipate from
27N65W to northwest Cuba Sun night into early Mon. A second cold
front will move off NE Florida Sun, then reach from Bermuda to the
Florida Straits by late Mon into early Tue, then start to stall
from 27N65W to central Cuba Tue night into Wed. Meanwhile,
northerly swell will continue to move through the waters north
through northeast of the Virgin and Leeward Islands into early
next week, then subside.

$$
GR/HVN
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