Tropical Weather Discussion
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000
AXNT20 KNHC 152338
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sat Oct 16 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
2300 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: An elongated area of low pressure is located
near 27N56W or about 550 nm southeast of Bermuda. A surface
trough extends from 27N53W to the low to 21N70W. Recent
satellite derived wind data show gale force winds within about
60 nm just south of the low center. A large area of fresh to
locally strong winds is also noted over the central Atlantic E
of the trough axis, roughly N of 22N between 48W and 62W. The
associated shower and thunderstorm activity remains disorganized,
with clusters of moderate to isolated strong convection covering
the waters mainly N of 23N E of the trough to 41W. This system
is beginning to merge with a larger mid-latitude trough. Strong
upper-level winds are expected to prevent additional tropical
development of this system as it accelerates to the east-
northeast over the next several days. Seas of 8 to 13 are
expected within the area of gales. The low is forecast to move N
of the forecast region late tonight into Sat morning.

Gulf of Mexico Gale Warning: A cold front will enter the NW Gulf
tonight with fresh to strong northerly winds following it. The
front will reach south central Florida to western Bay of Campeche
Sun morning with moderate to fresh N to NE winds across most of
the Gulf. Gale-force N winds will briefly move across the Mexican
waters Sat afternoon through evening and are then expected to
develop off of Veracruz early Sun through afternoon. Seas are
forecast to build to 8-10 ft with the strongest winds.

Please read the latest High Seas Forecast issued by the National
Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details
on both warnings.

...TROPICAL WAVES...

The axis of a tropical wave is near 29W south of 18N, moving W
at 10 to 15 kt. Scattered moderate convection is noted from 00N
and 10N between 25W and 35W.

The axis of a tropical wave is near 44W south of 18N, moving W
at around 10 to 15 kt. Scattered moderate convection is seen
from 03N and 13N between 40W and 50W.

The axis of a tropical wave is near 65W south of 17N, moving W
at around 10 to 15 kt. No deep convection is observed near the
wave axis.

The axis of a tropical wave is near 78W south of 19N, moving W
at 10 to 15 kt. Scattered moderate convection is observed over
the central Caribbean on either side of the wave axis and mainly
N of 13N between 74W and 78W.

The axis of a tropical wave is near 89W south of 19N, moving W
at 10-15 kt. The wave extends southward into the E Pacific
region. Scattered showers are near the northern end of the wave
axis over the Yucatan peninsula.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 09N14W
to 05N20W. The ITCZ continues from 05N20W to 06N27W to 06N43W to
the coast of French Guiana at 05N53W. Aside from convection
noted in the tropical waves section above, scattered moderate
convection is noted from 00N to 11N between 20W and 53W.

GULF OF MEXICO...

A weak ridge dominates the Gulf waters anchored by a 1016 mb high
pressure located over eastern Georgia. A surface trough remains
over the NE Gulf coastline with scattered moderate convection.
Light to gentle winds prevails across the Gulf waters based on
scatterometer data. Seas are in the 3-4 ft range over the NW
Gulf, and 1-3 ft elsewhere.

For the forecast, a cold front will enter the NW Gulf tonight
with fresh to strong northerly winds and building seas following
it. Please, see the Special Features section for more details
about the Gale Warning in effect for the SW Gulf waters.

CARIBBEAN SEA...

A couple of tropical waves are moving westward across the Caribbean
Sea. Please, see the Tropical Waves section for details.

A weak pressure pattern prevails across the basin due to the
presence of lows/troughs N of the Caribbean Sea. Gentle to
moderate winds are noted over eastern Caribbean mainly south of
14N. Light to gentle winds prevail elsewhere. Seas are in the 3-4
ft range over the eastern Caribbean and 1-3 ft elsewhere.

For the forecast, an upper level trough extending from the Bahamas
to the NW Caribbean will support active weather across the central
Caribbean and extreme NE Caribbean this weekend. A weak pressure
gradient across the Caribbean basin will lead to tranquil marine
conditions. A cold front will enter the SW N Atlantic over the
weekend and move SE, and bring a return to moderate trade winds
to the Caribbean Mon night.

ATLANTIC OCEAN...

Please refer to the Special Features section above for details on
the Gale Warning over the Atlantic waters associated with a low
center.

Aside from Special Features low, a weakening stationary front
extends from 31N30W to 29N40W to 31N50W to a 1007 mb low pressure
located N of area near just W of Bermuda near 32N64W. Recent
scatterometer data indicate fresh to locally strong S to SW winds
south of the front between 45W and 50W. The remainder of the
Atlantic forecast waters is under the influence of a ridge with a
1022 mb high pressure located N of the Madeira Islands. A pair
of tropical waves are between the W coast of Africa and the
Lesser Antilles. Please, see the Tropical Waves section for
details.

The Cumbre Vieja volcano, on the island of La Palma in the
Canary Islands, has been erupting since 19 September 2021.
Low ash concentrations moving NW. 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, the gale low pres will accelerate NE
and exit the region late tonight into early Sat morning. Active
weather associated with this system will persist across the SE
waters through tonight. A cold front will move southeastward off
the SE U.S. coast and across Florida by the end of the weekend,
reaching from Bermuda to the Florida Keys by Mon morning. Expect
fresh to strong N to NE winds behind the front through Mon
morning.

$$
ERA


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