[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162223
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Nov 17 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
2200 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough remains mainly inland over Africa extending
just offshore of the border of Guinea and Sierra Leone near 08N14W.
The ITCZ extends from 08N14W to 07N29W, then resumes west of a
surface trough from 05N33W to 04N43W. The surface trough extends
from 11N31W to 03N31W. Scattered moderate and isolated strong
convection is noted from 08N to 13N between 23W and 28W. Isolated
convection is noted west of the trough to 35W.

GULF OF MEXICO...

A 1025 mb high pressure positioned inland near Savannah, Georgia
maintains fairly tranquil weather conditions across the Gulf of
Mexico. Fresh winds are occurring in the SE Gulf waters, including
the Straits of Florida, where seas are 4 to 6 ft. Moderate
southerly winds are offshore the Texas and northern Mexico coast,
with 2 to 4 ft seas in the area. Gentle winds prevail elsewhere
with 1 to 3 ft seas.

For the forecast, the high pressure area will move east into the
western Atlantic and strengthen tonight into Wed. Fresh to locally
strong east winds will develop over the southeastern Gulf and
Straits of Florida tonight through Wed night. The next cold front
will enter the Gulf region on Thu, and move SE of the area late on
Fri. Fresh to strong northerly winds and building seas will
follow the front. Scattered showers and isolated thunderstorms are
expected ahead of this front.

CARIBBEAN SEA...

A stationary front extends from Central Cuba near 22N80W to
21N82W. A surface trough continues from 21N82W to 16N85W in the
vicinity of the Gulf of Honduras. Another surface trough is
located just to the south, offshore of Honduras and Nicaragua,
from 17N81W to 11N83W. The monsoon trough extends from the eastern
Pacific Ocean across Costa Rica to just north of Panama along
10N. Total precipitable water imagery shows a significant amount
of moisture in the western Caribbean. Scattered moderate and
isolated strong convection is noted over water from 09N to 22N
between 79W and 88W. Moderate to fresh easterly trade winds cover
most of the Caribbean Sea, except fresh to strong in the south-
central Caribbean. Seas are mainly 4 to 7 ft across the basin,
except locally to 8 ft offshore Colombia and eastern Panama.

For the forecast, the stationary front will dissipate tonight.
Strengthening high pressure over the western Atlantic combined
with Colombian low pressure will bring increasing trade winds
over the east and central Caribbean, including the Atlantic
passages tonight through Thu. A cold front is forecast to approach
the Yucatan Channel on Fri.

ATLANTIC OCEAN...

A cold front stretches from 31N60W to 25N72W, then transitions to
a stationary front and continues into central Cuba near 22N80W.
Scattered moderate convection is noted within 120 nm ahead of the
front, N of 30N. Moderate NE winds are occurring to the north and
west of the front, with fresh winds over the Bahamas and the
Straits of Florida. A weakening surface trough extends from 28N58W
to 22N60W with no significant associated convection. An upper-
level low is producing scattered showers and thunderstorms from
10N to 17N between 44W and 47W. The activity in this area are also
being enhanced by a surface trough that extends from 16N44W to
11N47W.

Farther east, a 1012 mb low pressure is near 29N32W. An
associated weakening occluded and cold front stretches ahead of
this low from 31N28W to 27N26W to 22N31W, with a surface trough
then continuing to 20N42W. Scattered moderate convection is noted
north of 28N between 26W and 31W. Strong winds and seas of 9 to
11 ft are likely occurring within 150 nm NW of the low pressure
center. Moderate to fresh trade winds and seas of 7-9 ft prevail
over the tropical Atlantic from 10N to 22N between 27W-61W. Mainly
gentle to moderate winds and 4 to 7 ft seas prevail elsewhere.

The Cumbre Vieja volcano, on the island of La Palma in the
Canary Islands, has been erupting since 19 September 2021.
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, the cold front will continue to move east,
leaving a stationary boundary near 22N through Wed as strong high
pressure builds over the western Atlantic. The pressure gradient
between the high pressure and the stationary front will lead to
increasing east winds and building seas south of about 28N from
Wed through late Thu. Looking ahead, a cold front will move
offshore NE Florida Fri, then stall from Bermuda to central Cuba
over the weekend. This front will be followed by fresh to strong
northeast to east winds and building seas north and northeast of
the Bahamas.

$$
Lewitsky
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