[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260410
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Tue Oct 26 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 0000 UTC surface analysis and satellite imagery through
0300 UTC.

...TROPICAL WAVES...

An Atlantic tropical wave is along 25W from 17N southward, moving
W at 10-15 kt. Scattered moderate convection is evident south of
the Cabo Verde Islands from 10N to 15N between 23W and 26W.

Regional sounding and satellite-derived wind data no longer show
definitive evidence of a tropical wave previously analyzed over
the eastern Caribbean. Weak evidence of a mid level trough is
evident east of the Leeward Islands, but this is likely associated
with a sharp upper trough over the region. Regional radar shows a
few showers associated showers east of the Leewards. Dry northerly
air aloft is suppressing any showers elsewhere over the eastern
Caribbean.

A Caribbean tropical wave has an axis along 79W from 18N
southward and moving W at 10-15 kt. No significant convection is
noted with this wave at this time.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends off the coast of Guinea-Bissau near
11N16W to 07N25W. The ITCZ extends from 07N25W to 06N42W to the
coast of Brazil near 04N51W. In addition to the convection
described in the Tropical Wave section, scattered moderate
convection is within 120 nm either side of the ITCZ.

...GULF OF MEXICO...

Divergence aloft associated with an upper anticyclone is
supporting a cluster of showers and thunderstorms over the north
coast of the Yucatan Peninsula currently. Isolated showers and
thunderstorms are active over the Straits of Florida related to
the tail end of an upper trough moving off the east coast into
the Atlantic, along with a thunderstorm off northwest Cuba, but
most of the earlier activity in this area has dissipated. A
trough over the western Florida Panhandle is supporting moderate
NW winds and 3 to 4 ft seas over the Florida Big Bend offshore
waters. A weak pressure pattern is in place across the remainder
of the Gulf, supporting light breezes and 1 to 3 ft seas.

Fore the forecast, fresh to strong southerly winds will develop
across the NW Gulf Tue night into Wed ahead of a cold front
expected to push off the Texas coast on Wed. The front will move
across the Gulf region through Thu night. Fresh to strong winds
are expected ahead and behind the front, with building seas to
12-13 ft in the wake of the front. Frequent gusts to gale force
are expected over the north-central and NE Gulf Wed night through
Fri before quickly diminishing early Sat.

...CARIBBEAN SEA...

A sharp upper trough extends from the central Atlantic near 30N52W
through Puerto Rico to the north central Caribbean. A few showers
are noted in regional radar on the southeast side of this upper
trough, moving quickly westward in the trade wind flow and mostly
staying over the Atlantic, but impacting the Leeward Islands,
Virgin Islands and Puerto Rico. Fresh to strong trade winds are
active over northwest Venezuela, the ABC Islands, and off
northeast Colombia, supporting a few showers over the south
central Caribbean and 5 to 7 ft seas. Fresh E winds are noted
over the Bay Islands and the Gulf of Honduras, with 4 to 5 ft
seas, and in the southeast Caribbean south of 15N. Moderate trade
winds and 3 to 5 ft seas are noted elsewhere, except for light SE
winds and slight seas over the northwest Caribbean.

For the forecast, weak ridge across the western Atlantic will
support fresh to locally strong trades across the eastern
Caribbean and tropical Atlantic waters east of the Windward
Islands through tonight. Winds are also expected to pulse fresh to
strong in the south- central Caribbean, including the Gulf of
Venezuela tonight. A cold front will enter the NW Caribbean Thu
evening and reach from W central Cuba to the Gulf of Honduras by
midday Fri.

...ATLANTIC OCEAN...

Low pressure continues to deepen north of the area off the
Carolinas, with an attendant cold front moving eastward over the
waters north of 28N off northeast Florida. Scattered showers and
thunderstorms are active ahead of the front and northeast of the
northern Bahamas, near 28N77W. Another cluster of showers and
thunderstorms is active near 27N74W. A scatterometer satellite
pass from 02 UTC confirmed strong to near gale force SW winds
within 300 nm east of the front, north of 28N. Seas are 6 to 9 ft
in this area. Farther east, a weak ridge extends from 1027 mb high
pressure near the Azores Islands westward to almost the central
Bahamas, disrupted somewhat by a trough near 50W north of 20N,
and a cold front north of the area over the north central
Atlantic. This pattern is supporting moderate trade winds south of
15N, and light to gentle winds elsewhere. Seas are 6 to 8 ft over
the tropical Atlantic with a component of N swell, and 4 to 6 ft
elsewhere, except 5 to 7 ft east of 35W.

The Cumbre Vieja volcano, on the island of La Palma in the Canary
Islands, has been erupting since 19 September 2021. Ash cloud
slowly drifting SW. Higher concentration over volcano and western
vicinity. 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 low pressure off the Carolinas
will move northeast through today and rapidly intensify. An
associated cold front moving eastward across the northern forecast
waters will produce fresh to strong southerly winds and building
seas expected ahead of it. A cold front will move off NE Florida
coast early today, and bring more fresh to strong winds across
the waters north of 27N. The next cold front is expected to sweep
across the region Thu night through Fri night bringing another
round of fresh to strong winds north of the Bahamas.

$$
Christensen
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