[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271003
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through
1000 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
today through Thu night. 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 late Wed night through Fri. Seas will build as high as 14 ft
in the wake of the front over the northern Gulf. A band of showers
and thunderstorms will be associated with the front.

...TROPICAL WAVES...

An Atlantic tropical wave is along 30W/31W from 18N southward,
moving W at 10-15 kt. Scattered moderate to isolated strong
convection is noted where the wave meets the ITCZ.

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 due to the presence of a ridge across
the Greater Antilles. 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 14N17W
to 11N28W. The ITCZ extends from 07N35W to the coast of French
Guiana. In addition to the convection described in the Tropical
Waves section, scattered moderate to isolated strong convection is
occurring from 04N to 09N between 17W and 41W.

GULF OF MEXICO...

A stationary front extends from west central Florida near Ft. Myers
to SE Louisiana. A few showers are near the frontal boundary. The
front is forecast to lift northward while dissipating. Light to gentle
winds are noted over the eastern Gulf. Southerly return flow is on
the increase over the western Gulf ahead of a cold front forecast
to enter the Gulf region later this morning. Recent scatterometer
data provided observations of mainly fresh SE-S winds N of 21N
and W of 96W. Seas are in the 3-5 ft range in association with
these winds. Seas of 1-3 ft prevail elsewhere across the Gulf
waters.

For the forecast, a cold front is expected to push off the Texas
coast later this morning. The front will move across the Gulf
region through Thu night. Frequent gusts to gale force and building
seas will accompany the front. Please, see the Special Features
section for more details.

CARIBBEAN SEA...

The Atlantic ridge extends across the Greater Antilles, with a
weak 1014 mb high pressure located over the Cayman Islands. 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 scatterometer data show fresh to strong winds
over the south-central Caribbean, particularly from 11N-13N
between 68W-75W, including the Gulf of Venezuela. Moderate to
fresh E winds are over the Gulf of Honduras. 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, then stall on Sun from eastern Cuba to near
Cabo Gracias a Dios, Nicaragua while dissipating.

ATLANTIC OCEAN...

A recent scatterometer pass showed fresh to strong W to NW winds
ahead and behind a cold front that extends from 31N70W to south-
central Florida. This front follows a frontal trough that stretches
from near Bermuda to the SE Bahamas. Scattered showers, with
embedded thunderstorms are noted ahead of the trough axis while a
narrow band of mainly low clouds and possible showers is associated
with the front. The remainder of the Atlantic forecast waters is
under the influence of a ridge anchored by a 1022 mb located near
the Azores. Seas are 6 to 9 ft in the area of fresh to strong
winds north of 29N between 60W and 78W, and 4 to 6 ft elsewhere
over open waters. A belt of moderate to fresh winds are noted
south of the ridge, except for fresh to locally strong NE winds
near the coasts of Morocco and Mauritania.

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. Medium to high concentration of volcanic ash
in the vicinity of the volcano. 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
31N70W to south-central Florida will reach from 31N67W to the
Straits of Florida today, and from 31N65W to the central Bahamas
by tonight. 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.

$$
GR
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