[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170949
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough remains mainly inland over Africa, reaching the
Atlantic through the coast of Guinea near 12N16W to 08N18W. The
ITCZ extends from 08N18W to 08N30W, then resumes west of a
surface trough from 05N37W to 04N45W. The surface trough extends
from 10N31W to 04N35W. Scattered moderate convection is noted
within 120 nm on all sides of these features.

GULF OF MEXICO...

High pressure has moved well east of the area into the Atlantic
and southerly return flow is setting up in advance of the next
cold front. No precipitation is present. Winds are fresh in the SE
Gulf and along the Texas coast, moderate elsewhere, except gentle
in the Bay of Campeche. Seas are 4 to 6 ft in the SE Gulf,
including the Florida Straits, 3 to 5 ft in the NW Gulf, and 1 to
3 ft elsewhere.

For the forecast, fresh E winds in the SE Gulf will gradually
diminish tonight as a cold front moves into the NW Gulf Thu. This
front will move SE of the basin Fri night. 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 surface trough extends from central Cuba to near Swan Island
near 18N84W. Another surface trough is noted just offshore Belize
and Yucatan coast. These boundaries combined with deep tropical
moisture and upper-level energy are producing numerous moderate to
isolated strong convection N of 13N, W of 79W. The rest of the
Caribbean is dry, except for scattered moderate convection noted
just off the coasts of Nicaragua, Costa Rica, and northern Panama,
in association with localized land breezes as well as the eastern
extension of the Pacific monsoon trough along 10N.

High pressure N of the Greater Antilles and lower pressure across
South America is translate to a tight pressure gradient over the
basin, and thus fresh winds encompass most of the basin. Strong to
near gale force winds are occurring offshore Colombia and adjacent
portions of the south central Caribbean, including offshore of
southern Hispaniola. Seas of 8 to 10 ft are occurring in this area
of higher winds, with 5 to 7 ft seas across the rest of the basin,
except 3 to 6 ft in the NW.

For the forecast, the surface troughs in the NW basin will
diminish by tonight. High pressure will strengthen and build
south through the basin, keeping the pressure gradient tight and
the area of strong winds to expand further, to include passages
off the Greater Antilles into Thu. A cold front is forecast to
approach the Yucatan Channel by Fri night.

ATLANTIC OCEAN...

A cold front enters the tropical Atlantic near 31N55W and extends
to 25N67W, where it transitions to a surface trough that continues
across the central Bahamas and into central Cuba. No significant
convection is occurring along this boundary. Fresh to locally
strong winds are occurring within about 200 nm N of the boundary,
especially just E of the central and NW Bahamas. A weak surface
trough extends from 29N58W to 23N60W and no deep convection is
present near the trough axis.

Farther east, a 1013 mb low pressure is near 28N33W. A weakening
surface trough associated with the low pressure extends from
29N29W to 24N30W to 20N41W. Scattered moderate convection is
noted N of 25N and between 25W and 31W. Fresh to locally strong
mainly easterly winds are noted N of the low between 26W and 40W.
Another surface trough extends from 15N46W to 09N49W, with
scattered moderate convection noted within 150 nm of the trough
axis.

Aside from the winds near the cold front and low pressure, to the
W of 40W, mainly moderate winds prevail. Gentle winds are occurring
E of 40W, except fresh winds offshore Western Sahara. Seas across
the basin are broadly 5 to 9 ft, highest S of 15N, near the low
pressure, and behind the cold front N of 29N.

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 aforementioned cold front will continue to
move E, and the trough will dissipate today as high pressure
builds over the western Atlantic. This will lead to increasing E
winds and building seas S of about 28N tonight through Thu night.
Looking ahead, a cold front will move offshore NE Florida by 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.

$$
KONARIK
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