[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 252342
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 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 1800 UTC surface analysis and satellite imagery through
2230 UTC.

...TROPICAL WAVES...

An Atlantic tropical wave has an axis along 24W from 17N
southward, moving W at 10-15 kt. Scattered moderate convection is
noted south of the Cabo Verde Islands from 06N to 15N between 23W
and 26W. Fresh to strong trades are noted in earlier satellite-
derived data near the wave.

A Caribbean Sea tropical wave has an axis along 64W from 18N
southward and is moving W at 10 kt. No significant convection is
noted with this wave at this time.

A Caribbean tropical wave has an axis along 78W 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 The Gambia/Senegal
near 13N17W to 07N24W. The ITCZ extends from 07N26W to 06N42W to
the coast of Brazil near 04N51W. Scattered moderate convection is
within 250 nm of the monsoon trough. Scattered moderate convection
is also noted within 150 nm on either side of the ITCZ.

...GULF OF MEXICO...

An upper level trough across the central United States and a
developing low pressure off the Georgia coast are providing a
favorable upper level pattern for scattered moderate to isolated
strong convection to flare up in the SE Gulf of Mexico. Most of
the convection continues to be S of 25N and E of 85W, affecting
portions of the Florida Keys and Florida Straits. A surface
trough is analyzed in the central Bay of Campeche but not
producing any significant convection. Weak pressure gradient
results in moderate or weaker anticyclonic winds prevailing across
the basin. However, stronger winds are likely in the areas of
showers and thunderstorms. Seas of 2-4 ft are present N of 20N and
1-3 ft elsewhere.

For the forecast, a weak ridge along 25N will dominate the Gulf
waters through Tue and produce gentle to moderate winds. 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 ft in the wake of the front. Gale
force W winds are expected behind the front and N of 26N Thu
afternoon through early Fri afternoon before quickly diminishing
early Sat.

...CARIBBEAN SEA...

Aside from the storm activity associated with the tropical waves,
only a few showers and isolated thunderstorms are noted near the
coast of Panama and SE Costa Rica. A dry airmass dominates the
rest of the basin, providing fairly tranquil weather conditions. A
modest pressure gradient between the high pressure in the NW
Atlantic and lower pressures in South America result in fresh to
locally strong trades in the central and eastern Caribbean Sea,
with the strongest winds occurring within 100 nm of NW Colombia
and in the SE Caribbean based on earlier scatterometer satellite
data. Seas of 5-8 ft are found in the central, southwest and
eastern Caribbean Sea, with the highest seas occurring off the NW
Colombian coast. Moderate to locally fresh, especially in the Gulf
of Honduras, and seas of 2-5 ft are present elsewhere in the
basin.

For the forecast, a weak ridge persists across the W Atlc to the
east of 75W. The associated pres gradient across the Caribbean
will support fresh to locally strong trades across the eastern
Caribbean and tropical Atlc waters E 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...

An intensifying low pressure system off the U.S. East Coast and a
surface trough extending SW to southern Florida are producing a
large area of showers and thunderstorms, mainly W of 72W and N of
Cuba, impacting portions of the NW Bahamas. Earlier scatterometer
satellite data indicated that fresh to strong winds are occurring
W of 70W and N of 26N. Elsewhere in the basin, a weak surface
trough extends from 27N44W to 20N47W, but it is not producing any
deep convection. Another weak surface trough peeks into the
tropical Atlantic, entering the region near 31N50W to 29N54W. A
few showers are seen near and east of the trough axis, N of 29N
between 45W and 53W.

An expansive 1031 mb Azores ridge patrols the rest of the
tropical Atlantic, promoting fairly tranquil weather conditions.
The pressure gradient between the high pressure system and lower
pressures in South America result in fresh to strong trades from
05N to 19N and between 33W and the Lesser Antilles. Seas in this
region are in the 7-10 ft range, with the highest seas occurring a
couple of degrees east of the Windward Islands. Another area of
fresh to strong NE winds is found in the E Atlantic from 15N to
22N and E of 30W. Seas of 3-6 ft are prevalent W of 60N and 5-8 ft
are present elsewhere in the basin.

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 W of 65W, weak ridge extends from the central
Atlc westward to 75W. 1007 low pres offshore of S Carolina will
move NE through Tue and rapidly intensify. An associated frontal
trough 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
Tue, and bring more fresh to strong winds across the waters N of
27N. A 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.

$$
AReinhart
This weather bulletin was brought to you by:
www.nashvilleweather.net