[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231803
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sat Oct 23 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 1200 UTC surface analysis and satellite imagery through
1630 UTC.

...TROPICAL WAVES...

An Atlantic tropical wave is near 51W from 16N southward to near
the French Guiana-Brazil border, and moving W at 15 to 20 kt.
Scattered showers and isolated thunderstorms are noted over NW
French Guiana and adjacent waters.

A Caribbean tropical wave is along 68W from 18N southward to W
Venezuela, and moving W near 20 kt. Subsidence and drier air aloft
is hindering any significant convection near this wave.

Another Caribbean tropical wave is near 76W from SE Cuba southward
across Jamaica to NW Colombia, and moving W at 15 to 20 kt.
Scattered showers and thunderstorms are occurring across W
Colombia, W Panama and nearby waters.

A third Caribbean tropical wave is along 84W from 21N southward
across Honduras, Nicaragua and Costa Rica to the Pacific Ocean;
and moving W near 15 kt. Scattered showers and isolated
thunderstorms are seen over the SW Caribbean Sea, including the
coast of Nicaragua and Costa Rica.

...MONSOON TROUGH/ITCZ...

A monsoon trough exits through the African coast near Guinea-
Bissau/Guinea border at 11N15W through a 1011 mb low near 10N16W
to well S of the Cabo Verde Islands at 07N22W. The ITCZ then
continues from 07N22W to 04N42W. Scattered to numerous moderate to
isolated strong convection is found near the monsoon trough from
04N to 08N between 14W to 29W. Scattered showers and isolated
thunderstorms are evident near the low from 09N to 14N between the
NW African coast and 19W. Based on the latest analysis, no
significant convection is present near the ITCZ.

...GULF OF MEXICO...

A surface trough and an embedded 1010 mb low pressure at the W
Bay of Campeche near 21N94W are generating scattered showers and
isolated thunderstorms over the N Bay of Campeche and near the N
Yucatan Peninsula. A modest stationary front curves southwestward
from N Florida across the N Gulf to near New Orleans. Scattered
showers are present just S of this boundary from the NW Gulf
east-southeastward through the central Gulf to central Florida.
Gentle to moderate winds and seas of 2 to 4 ft are found across
much of the Gulf, except locally fresh winds with seas up to 5 ft
near showers and thunderstorms.

For the forecast, the stationary front will linger across the
N central and NE Gulf today before dissipating tonight. Gentle to
moderate winds will prevail across the basin through the weekend
and become light to gentle by early next week.

...CARIBBEAN SEA...

Refer to the Tropical Waves section for details on convection
across the Caribbean Basin. Otherwise, the latest satellite
scatterometer and model data reveal moderate to fresh ENE to E
trades with seas of 6 to 8 ft across the central and E basin.
Moderate to gentle E to ESE trades and seas of 2 to 5 ft prevail
for the W basin.

For the forecast, high pressure N of the area will support fresh
to locally strong trades E of the Windward Islands and across the
E Caribbean through the early next week. Winds are also expected
to pulse fresh to strong in the Venezuela Basin tonight through
Mon evening. By Tue and Wed, gentle to moderate trade winds are
expect to prevail across the basin.

...ATLANTIC OCEAN...

A surface trough curves southwestward from SW of Bermuda at 28N71W
across the central Bahamas to N Cuba. Scattered showers and
thunderstorms are evident from the central Bahamas northeastward
to S and E of Bermuda. Farther E, a shear line stretches west-
southwestward from well SW of the Azores across 31N39W to SE of
Bermuda at 29N53W. Scattered showers and isolated thunderstorms
are noted N of 28N between 40W and 53W. Refer to the Tropical
Waves and Monsoon Trough/ITCZ sections above for additional
convection across the Atlantic Basin.

Gentle to moderate with locally fresh trades and seas of 5 to 8 ft
are present N of 16N between the NW African coast and 71W. W of
71W, gentle to moderate S to SW winds and seas at 2 to 4 ft are
seen from the Greater Antilles northward to 31N. Moderate to
fresh NE trades and seas of 8 to 10 ft are found from 05N to 16N
between 36W and the Lesser Antilles. Gentle to moderate with
locally fresh winds and seas at 5 to 7 ft prevail for the rest of
the basin.

The Cumbre Vieja volcano, on the island of La Palma in the Canary
Islands, has been erupting since 19 September 2021. Continues ash
emission is noted with small column height. Medium to high
volcanic ash concentration 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 W of 65W, a trough extending across the NW
Bahamas and off the southeast Florida coast will support
convection across the region today. Meanwhile, a stationary front
stretches across N Florida and adjacent Atlantic waters from
31N78W to 29N81W. This front will slowly meander southward toward
S Florida and the NW Bahamas today and stall by Sun. The front is
expected to dissipate by Mon morning. Moderate to locally fresh
winds will develop N of this boundary on Sun off the Florida
coast. Expect showers and thunderstorms along this boundary
through the weekend.

$$

Chan
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