[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 232225
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Nov 24 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
2000 UTC.

...SPECIAL FEATURES...

Atlantic Ocean Gale Warning: A strong cold front from 31N67W to
across the central Bahamas to central Cuba has strong to gale-
force NW-N winds north of 30N between 66W and 77W with peak seas
of 12 to 14 ft. These conditions will persist this evening as the
front continues east-southeast, with gale-force winds diminishing
late tonight into early Wed. Please see the latest NWS High Seas
Forecast issued by the National Hurricane Center at
website://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more
information.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the western coast of Africa
extending offshore from the Guinea and Guinea-Bissau border near
11N15W to 10N17W. The ITCZ extends from 10N17W to 06N30W to
08N48W. Scattered moderate and isolated strong convection is
noted from 06N to 08N between 15W and 18W, and from 05N to 07N
between 31W and 35W. Scattered moderate convection is noted from
10N to 12N between 20W and 25W, and from 03N to 08N between 35W
and 44W.

GULF OF MEXICO...

A cold front extends from south of the Yucatan Channel in the NW
Caribbean Sea to across the northern Yucatan Peninsula just north
of 20N to the SW Gulf of Mexico near 22N96W. A residual trough is
noted along and just offshore of the coast of NE Mexico from near
the Texas border to just east of Tampico. No significant
precipitation is noted along this boundary, however isolated to
scattered showers are possible. Fresh to strong winds that were
occurring in the central and eastern Gulf have diminished to
moderate to fresh in the past few hours. Fresh to strong NW-N
winds are funneling offshore of Veracruz. Otherwise, gentle to
moderate winds prevail. Remnant 6 to 10 ft seas are in the Gulf
east of 89W with mainly 4 to 7 ft seas elsewhere, except 2 to 4 ft
west of the Yucatan Peninsula to 94W.

For the forecast, the cold front will move completely south of
the region by this evening. Fresh winds in the southern Gulf will
gradually diminish as high pressure builds in behind the front.
The high will quickly move east allowing for fresh southerly winds
to develop in the NW Gulf by Wed night, along with fresh E winds
in the Straits of Florida and adjacent SE Gulf. The next cold
front will move off the Texas coast Thu, then reach a Tampa Bay to
Veracruz, Mexico, line Fri. Fresh to strong winds are expected
behind the front over the far western Gulf Thu night into Fri
night, with near gale force winds possible in the nearshore waters
between Tampico and Brownsville. Winds will diminish Sat.

CARIBBEAN SEA...

A cold front extends from eastern Cuba near 21N77W to south of the
Cayman Islands to near the Gulf of Honduras. A pre-frontal trough
extends from near the eastern tip of Cuba to just north of
Jamaica. Scattered showers and isolated thunderstorms are noted in
the vicinity of the front. A secondary cold front is not far
behind, extending from central Cuba to near Cozumel, Mexico.
Earlier scatterometer data showed fresh to strong N-NE winds
between the fronts, with 5 to 7 ft seas, locally higher near the
Yucatan Channel. Another surface trough is noted in the western
Caribbean from 17N76W to 12N79W. Isolated showers and
thunderstorms are in the vicinity of the trough axis. The monsoon
trough extends from the eastern Pacific Ocean to across Costa Rica
and Panama across the SW Caribbean along 10N. Scattered moderate
and isolated strong convection extends across this area from south
of 13N between NW Colombia and Costa Rica. Mainly gentle to
locally moderate winds and seas of 2 to 4 ft prevail across the
basin ahead of the leading cold front.

For the forecast, the two cold fronts will combine tonight, then
reach from Haiti to Nicaragua Wed. The merged cold front will then
become stationary Thu from the Mona Passage to S of Jamaica,
where it will gradually dissipate through the end of the week.
Fresh NE winds will occur behind the front, with some locally
strong winds possible south of Hispaniola. Showers and
thunderstorms will also increase over Hispaniola and Puerto Rico
late this week, bringing a potential for heavy rain. Moderate
northerly swell will affect the NE Caribbean passages and the
Tropical N Atlantic waters Thu into the weekend.

The heavy rainfall following the front will affect Hispaniola and
Puerto Rico beginning on Thu and will persist as the front stalls
through the latter part of the week. Eastern portions of Puerto
Rico have the highest risk for moderate to heavy rainfall amounts.

ATLANTIC OCEAN...

Please see the Special Features section above for more details on
the gale-force wind event over portions of the SW N Atlantic,
north of 30N between Bermuda and 77W.

A cold front extends from near Bermuda to 31N65W to across the
southeast Bahamas to eastern Cuba near 21N76W. A secondary cold
front extends from 31N67W to across the central Bahamas to central
Cuba near 22.5N79.5W. A pre-frontal trough east of the first
front extends from 27N65W to across the Turks and Caicos Islands
to near the eastern tip of Cuba. Numerous showers and scattered
thunderstorms are noted north of 22N within 210 nm east of 70W and
east of the leading cold front. Fresh to strong NW-N winds are
occurring north of 26N and west of the secondary front where seas
are also 8 ft or greater. Seas are the highest, 12 to 16 ft, north
of 29N between 73W and 80W. Fresh to strong S-SW winds are
occurring north of 26N within 300 nm ahead of the leading front.
Seas are 7 to 11 ft across this same area. Moderate to fresh winds
cover the remainder of the area north of 22N and west of 55W, with
gentle to moderate winds south of 22N and west of 55W. Seas are 5
to 8 ft south of 26N.

Farther east, a surface trough extends from 31N35W to 24N48W. A
dissipating cold front extends from 31N23W to 26N28W where it
continues as a trough to 20N40W. These surface features reside
within a broad area of upper-level cyclonic flow, with a large
upper-level low centered north of the area. Two pockets of
scattered moderate convection are noted, one from 20N to 26N
between 22W and 30W, and the other from 25N to 31N between 30W and
42W. Seas are 6 to 10 ft north of 23N between 35W and 55W in
northerly swell. High pressure of 1018 mb is noted near the
Canary Islands with a ridge axis extending from southwest of the
dissipating front and trough. Mainly gentle to moderate winds and
seas of 5 to 7 ft in mixed swell dominate the open waters of the
tropical Atlantic, except light near the ridge axis.

The Cumbre Vieja volcano on the island of La Palma in the Canary
Islands has been erupting since 19 September 2021. 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, the two fronts will merge tonight and reach
from 23N65W to Haiti Wed, then stall along 20N through the end of
the week. North of 27N, strong S winds can be expected ahead of
the front with strong NW winds behind it. North of 29N, to the
southeast of Bermuda, NW gales will persist into this evening. In
the wake of the front, high pressure will build in off the coast
of Georgia and northern Florida on Thu. The next cold front is
likely to bring fresh to strong winds Fri into Sat to waters north
of 29N.

$$
Lewitsky
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