[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040532
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Sat Dec 4 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 0000 UTC surface analysis and satellite imagery through
0510 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the southern coastal areas of
Guinea near 09N14W, to 08N17W. The ITCZ continues from 08N17W to
05N25W to the Equator along 34W. Precipitation: scattered strong
is within 60 nm to 120 nm to the north of the ITCZ between 21W and
30W. Scattered moderate to strong is from 05N to 07N between 26W
and 33W. Widely scattered moderate to isolated strong is from 06N
southward between 33W and 37W. Scattered strong is from 01S to 01N
between 46W and 51W, in the coastal plains and the coastal
waters of Brazil.

One surface trough is along 10N41W 04N40W. Precipitation: isolated
moderate to locally strong is from 10N southward between 37W and
42W. A second surface trough is along 07N48W 02N46W.
Precipitation: isolated moderate is within 60 nm on either side of
the second surface trough.

GULF OF MEXICO...

A surface trough is along 28N91W, 24N91W, 17N90W in the Yucatan
Peninsula. Precipitation: isolated moderate is within 150 nm on
either side of the surface trough from the southern coastal plains
of Louisiana to the Yucatan Peninsula. Fresh winds are within 90
nm of the coast of the Yucatan Peninsula. Moderate wind speeds or
less cover the rest of the Gulf of Mexico.

Surface anticyclonic wind flow covers the rest of the Gulf of
Mexico that is to the east of the surface trough. A 1024 mb high
pressure center is near 29N87W.

High pressure in the northern Gulf will shift slowly ESE across
the basin through Sun, supporting tranquil conditions for the next
few days. A weak cold front is expected to enter the NW Gulf,
briefly, late Mon then move northward out of the basin Tue. The
next front is expected to enter the NW Gulf Wed.

CARIBBEAN SEA...

The GFS model for 500 mb shows an inverted trough that extends
from Costa Rica to NE Nicaragua. Precipitation: widely scattered
moderate to isolated strong is in the coastal plains and in the
coastal waters western Panama to 210 nm to the NE of eastern
Honduras.

The monsoon trough passes through Colombia near 10N74W,
beyond western Panama/southern Costa Rica, and into the eastern
Pacific Ocean. Precipitation: scattered to numerous strong is
within 100 nm to the south of the monsoon trough, between Colombia
and 80W.

Isolated moderate rainshowers are associated with broken to
overcast low level clouds, that are moving with the low level wind
flow, in the remainder of the Caribbean Sea.

Near gale-force winds are within 120 nm of the coast of Colombia
between 73W and 76W. Strong winds are within 240 nm of the coast
of Colombia between 71W and 78W. Strong winds are moving through
the Windward Passage. Moderate to fresh winds cover the rest of
the area that is between 70W and 80W. Fresh winds are within 180
nm of the coast of the Yucatan Peninsula. Moderate winds cover
the remainder of the Caribbean Sea from 70W eastward. The sea
heights range from 7 feet to 8 feet within 210 nm of the coast of
Colombia. The sea heights range from 4 feet to 6 feet elsewhere.

Weak high pressure north of the area will maintain moderate to
fresh NE to E winds in the Caribbean Sea into next week, with
fresh winds pulsing to strong at night off Colombia and the Gulf
of Venezuela, and south of Hispaniola. NE winds also will pulse
to strong each night through the Windward Passage through Sat
night. Moderate NE to E swell in the Tropical N Atlantic Ocean is
expected to continue for the next several days. Active weather
will continue in the western Caribbean Sea through Sun.

ATLANTIC OCEAN...

A western Atlantic Ocean upper level trough is supporting a
surface trough, that is extending from a 1011 mb low pressure
center that is near 33N58W, through 31N59W, to 21N64W.
Precipitation: isolated moderate to locally strong is from 180 nm
to 360 nm to the east of the surface trough. Fresh to strong
southerly winds are within 360 nm to the east of the surface
trough. The sea heights range from 5 feet to 7 feet within 600 nm
to the east of the surface trough. The sea heights range from 3
feet to 5 feet, and gentle-to-moderate wind speeds or less, cover
the Atlantic Ocean from the surface trough westward.

Broad upper level cyclonic wind flow, and comparatively drier air
in subsidence that is apparent in water vapor imagery, cover the
Atlantic Ocean from 20N northward from 42W eastward.

A tight surface pressure gradient, to the south of the Azores high
pressure center, is supporting fresh to strong winds from 10N
northward from 40W eastward. The sea heights in the same area
range from 8 feet to 11 feet. Fresh wind speeds cover the waters
that are from 10N to 20N between 40W and 54W.

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/.

Weak high pressure across the northern Gulf of Mexico and eastern
U.S. will build slowly south and east into the area through early
next week, supporting generally tranquil conditions over the SW N
Atlantic for the next several days. Moderate NE to E swell over
the Atlantic waters E of 70W is expected for the next several
days. Moderate to fresh southerly winds are expected offshore of
the N Florida waters Wed.

$$
MT
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