[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101746
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Wed Nov 10 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.

...SPECIAL FEATURES...

Showers and thunderstorms have decreased near the center of a
hurricane-force non-tropical low pressure system located a little
over 500 miles ENE of Bermuda. While a large area of shower
activity associated with a frontal boundary persists to the NE of
the low's center, the system has not yet acquired sufficient
characteristics to be classified as a subtropical cyclone.
However, some additional development is still possible during the
next day or two while upper-level winds become a little more
favorable, and a subtropical storm could form during this time.
This system has a medium chance of development in the next 48
hours. Additional information on this system can be found in the
Tropical Weather Outlook issued by the National Hurricane Center
at website - nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2 and in High
Seas Forecasts issued by the National Weather Service at website -
ocean.weather.gov/shtml/NFDHSFAT1.php

....MONSOON TROUGH/ITCZ...

A monsoon trough exits the coast near the Guinea-Bissau/Guinea
border at 11N15W to 08N18W. An ITCZ then continues from 08N18W to
07N36W to 06N54W, near the Suriname-French Guiana border.
Scattered moderate to isolated strong convection is occurring near
both the ITCZ and monsoon trough from 05N to 09N between 14W and
49W. Scattered moderate convection is seen farther W near the ITCZ
from 06N to 11N between 35W and 55W.

The E Pacific monsoon trough is triggering scattered heavy showers
and isolated thunderstorms over Costa Rica and Panama, and nearby
Caribbean waters.

...GULF OF MEXICO...

A surface ridge extends southwestward from a 1024 mb high over the
Georgia-Alabama border across the central Gulf to E Mexico. This
feature is promoting gentle to moderate E to SE winds and seas at
2 to 4 ft across the entire Gulf.

For the forecast, the ridge will sustain gentle to moderate E-SE
winds today. Southerly return flow increases slightly across the
NW Gulf tonight, then winds across the basin will diminish early
Thu. The next cold front will move into the N Gulf Thu into Thu
night, then stall Fri. Reinforcing high pressure will push the
front across the Gulf this weekend with fresh to strong northerly
winds behind it. The front will reach the SE part of the basin by
Sat night, moving well SE of the area by the end of the weekend.

...CARIBBEAN SEA...

A cold front extends southwestward across the W Atlantic to the
Windward Passage at 20N74W, then continues as a shearline to the
SW basin off the Honduras-Nicaragua coast. Scattered showers and
isolated thunderstorms are evident up to 80 nm on both sides of
the cold front/shearline. A surface trough near 18N86W is
triggering similar conditions across the NW basin, including the
Gulf of Honduras. Refer to the Monsoon Trough/ITCZ section for
additional convection in the basin. Latest satellite scatterometer
and wave model data showed moderate to fresh N to NE winds with
seas at 4 to 6 ft NW of the shearline across the NW basin. Gentle
to moderate NE to E trades and seas of 2 to 4 ft prevail for the
rest of the basin.

For the forecast, moderate to fresh trades will continue to
dominate the basin today, while the tail end of a cold
front/shearline slides east. As a high builds N of the Caribbean
Sea, expect fresh to locally strong trade winds across the S
central Caribbean, and in the Gulf of Venezuela beginning tonight.
These winds will likely persist through Fri. A new cold front is
forecast to move into the NW Caribbean by the end of the upcoming
weekend.

...ATLANTIC OCEAN...

A cold front curves southwestward from N central Atlantic across
31N53W through E Cuba/Windward Passage. Scattered showers and
isolated thunderstorms are present up to 80 nm SE, and 200 nm NW
of the front, including the central and SE Bahamas. An upper-level
low SW of the Canary Islands near 27N26W is producing scattered
showers N of 14N between the NW African coast and 24W, including
the Cabo Verde Islands. A surface trough is causing scattered
showers and isolated thunderstorms near NE Brazil and adjacent
Atlantic waters. Refer to the Monsoon Trough/ITCZ section for
additional convection in the basin. Moderate to fresh SE to W to
NW winds with seas at 11 to 13 ft are found near the cold front, N
of 27N between 50W and 64W. Gentle to moderate with locally fresh
N to NE winds and seas of 7 to 10 ft are found behind the front, N
of 21N between 63W and Georgia-Florida coast/Bahamas. A 1016 mb
high over the central Atlantic near 28N43W is providing light to
gentle winds and seas of 4 to 5 ft N of 20N between 25W and 50W.
Gentle to moderate NE winds and seas at 5 to 6 ft are noted near
the Canary Islands N of 23N between the NW African coast and 23W.
Gentle to moderate NE trades and seas of 4 to 5 ft exist from 07N
to 20N between 30W and the Lesser Antilles. Moderate to fresh NNE
to NE trades and seas at 5 to 7 ft are found N of 06N between the
Mauritania-Senegal coast and 30W. Light to gentle ESE to SE trades
and seas of 3 to 4 ft prevail for the remainder of the basin.

For the forecast west of 65W, the cold front will continue moving
SE through Thu, stalling and dissipating along 22N by Fri. Large
seas following the front will gradually subside through the end
of the week. The next cold front will move off NE Florida on Fri,
then stall. Reinforcing high pressure will push the front across
the region on Sat into Sun.

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 latest Volcanic Ash Advisory issued by
Meteo-France at website https://vaac.meteo.fr/volcanoes/la-palma/

$$

Chan
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