Tropical Weather Discussion
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000
AXNT20 KNHC 270508
TWDAT

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

...SPECIAL FEATURES...

Gulf of Mexico Gale Warning: Strong to near gale force winds will
follow a cold front expected to move through the Gulf of Mexico
Wed through Thu. Water temperatures are still relatively warm
over the Gulf of Mexico. The cooler air following the front will
move over the warmer waters and allow gale force winds in the
lower levels of the atmosphere to mix to the surface over the
north- central and northeast Gulf. Therefore a gale warning for
frequent gusts to gale force has been issued for these area valid
from Wed night through Fri. Seas will build as high as 14 ft in
the wake of the front over the northern Gulf. A squall line
containing strong to severe thunderstorms with very strong wind
gusts is expected to accompany the cold front as it moves from
west to east Wed afternoon through Thu morning. The strongest
thunderstorms should occur over the northwest and north-central
Gulf with the line, Wed afternoon through Wed night.

...TROPICAL WAVES...

An Atlantic tropical wave is along 28W from 18N southward, moving
W at 10-15 kt. Scattered moderate to isolated strong convection
is evident from 05N to 07N between 25W and 30W.

A recent ship observation showing NE winds between Colombia and Jamaica
indicated there may be a surface trough along 74W/75W, but extending
no farther north than 15N/16N into the ridge axis farther north.
A deep layer trough moving through the Bahamas toward the Windward
Passage is providing support for the surface trough. A few showers
and thunderstorms are active along this feature off the coast of
Colombia near Barranquilla and Cartagena. This feature will move
little over the next couple of days, and gradually become absorbed
into a broader area of low pressure centered over the southwest
Caribbean.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends off the coast of Senegal near 13N17W
to 11N28W. The ITCZ extends from 07N30W to 07N40W to 04N50W. In
addition to the convection described in the Tropical Waves
section, scattered moderate to isolated strong convection is
occurring on either side of the ITCZ, from 06N to 08N between 30W
and 40W.

GULF OF MEXICO...

A cold front extends from west central Florida near Sarasota to
28N87W, where it becomes stationary to southwest Louisiana. Light
to gentle breezes follow the front, and it may be starting to
weaken and stall over the eastern Gulf. Gentle to moderate SE
winds and 3 to 5 ft seas are noted off Texas and northern Tamaulipas,
with light to gentle SE winds and 1 to 3 ft elsewhere. A few
showers are noted north of the front over the northeast Gulf, but
no significant shower or thunderstorm activity is noted elsewhere.

For the forecast, fresh to strong southerly winds will develop
across the NW Gulf tonight into Wed ahead of the cold front
expected to push off the Texas coast on Wed morning. 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 12-14 ft in the wake of the front by Thu.
Frequent gusts to gale force are forecast over the north-central
and NE Gulf Wed night through Fri before quickly diminishing early
Sat.

CARIBBEAN SEA...

The Atlantic ridge extends from northeast of the region across
Hispaniola and Cuba. A 1014 mb high was analyzed off southwest
Haiti along the ridge axis. The ridge was displaced southward
ahead of a deep layer trough and associated cold front currently
north of the region moving through the Bahamas. Recent
observations and data from a scatterometer satellite pass from
0140 UTC showed moderate to fresh winds trade winds south of 15N,
with fresh to strong E winds over the Gulf of Venezuela. The same
pass along with observations from Roatan indicated fresh winds
off Honduras through the Bay Islands. Gentle to moderate E to SE
winds are noted elsewhere. Seas are 4 to 6 ft in most areas.

For the forecast, the position of the surface ridge will continue
to support moderate to fresh trades across the south-central
Caribbean, including the Gulf of Venezuela through early Thu.
Gentle to moderate SE to S winds will prevail over the NW
Caribbean through Thu night ahead of a cold front forecast to
reach western Cuba and the NW Caribbean. The front will extend
from western Cuba to the Gulf of Honduras by midday Fri, and from
central Cuba to NE Honduras on Sat.

ATLANTIC OCEAN...

A recent scatterometer satellite pass showed fresh to strong W to
NW winds following a cold front reaching from 31N73W to central
Florida. This front follows another boundary reaching from near
Bermuda to the northern Bahamas. Divergence aloft ahead of deep
layer trough supporting both these features is responsible for
clusters of moderate to strong convection east of the fronts from
25N to 27N between 62W and 65W, and north of 30N between 65W and
67W. Elsewhere, a surface ridge extends from 1026 mb high pressure
near the Azores southwestward to Hispaniola. Seas are 6 to 9 ft
in the area of fresh to strong winds north of 26N between 50W and
75W, and 4 to 6 ft elsewhere over open waters. Moderate trades are
noted south of the ridge, except for moderate to fresh NE winds
off northwest Africa, and light to gentle breezes elsewhere.

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 cold front extending from
31N73W to central Florida will reach from 31N67W to the Straits of
Florida on Wed, and from 31N65W to the central Bahamas by Wed
night. The front will dissipate over the SE waters on Thu. The
next cold front is expected to sweep across the region Thu night
through Fri night, then stall from 31N68W to eastern Cuba during
the upcoming weekend. Fresh to strong winds and building seas are
expected on either side of these fronts.

$$
Christensen


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