[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 282311
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Mon Nov 29 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
2300 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 08N13W
to 05N20W. The ITCZ continues from 05N20W to 01N50W. Scattered
moderate convection is noted from 03N to 13N between 21W and
40W.

GULF OF MEXICO...

A stationary front extends from the SE Gulf near 25N83W to a
1015 mb surface low centered off the Texas coast near 27N92W. A
cold front stretches from the low center to near 22N97W. Surface
observations along with a recent scatterometer satellite pass
indicate strong NE winds of 30 kt to the N of the low, with 20-25
kt NW winds in the wake of the front with 4 to 7 ft seas. Weak
high pressure dominates the pattern elsewhere across the basin,
supporting light to gentle winds and slight seas.

For the forecast, the low pressure will move across the central
Gulf through Mon then dissipate across the southeast Gulf along
with the front. A reinforcing cold front is expected to enter the
northeast Gulf early Mon and move across the eastern Gulf
through Tue night, allowing high pressure to build over the
northern Gulf through Thu.

CARIBBEAN SEA...

Weak high pressure located N of the Caribbean is supporting
fresh to locally strong trade winds near the coast of Colombia
and just S of Hispaniola, with 4 to 6 ft seas. Fresh northerly
winds are off the Atlantic coastline of Nicaragua. Light to
gentle winds persist elsewhere with 2 to 4 ft seas, except a
little higher near Atlantic passages where N swell persists.
Scattered showers and thunderstorms are noted north of Panama,
and also near the Nicaragua/Costa Rica border. A diffluent
pattern aloft is helping to induce this convective activity.
Elsewhere, shallow moisture embedded in the trade wind flow will
continue to move across the region producing isolated to
scattered passing showers. A surface trough crosses the US/UK
Virgin Islands and extends into the eastern Caribbean to near
13N66W. Some shower activity is noted near the northern end of
the trough axis affecting the Atlantic waters of Puerto Rico.

For the forecast, moderate to fresh NE to E winds will persist
over all but the NW Caribbean through Mon before a cold front
sinks slowly southward across the northwest Caribbean Mon night,
then stalls along 20N and dissipates Wed. High pressure north of
the front will induce strong trade winds across the south central
Caribbean Tue night through Fri night. Moderate N to NE swell
will continue across the Atlantic waters east of 70W and through
the NE Caribbean passages through Mon tonight.

ATLANTIC OCEAN...

A cold front enters the Atlantic forecast area near 31N65W and
continues SW to the NW Bahamas. Mainly light winds are noted
near the frontal boundary based on scatterometer data with the
exception of gentle to moderate NW winds just off NE Florida.
Weak high pressure of 1019 mb follows the front. Large northerly
swell has been moving across the Atlantic waters east of 60W over
the past couple of days, but this is starting to subside from
west to east. Another set of long period NE swell will propagate
across the waters E of the Bahamas tonight building seas to 4-7
ft, highest E f 70W.

For the forecast west of 65W, the reinforcing cold front is
moving southeastward across the waters off northeast Florida this
afternoon, and will reach from Bermuda to the Florida Keys by
Mon evening, then weaken and stall from 27N65W to central Cuba
Tue through Wed. Meanwhile, a mix of northerly swell will
continue to move through the waters east of the Bahamas into
early next week, then subside Mon night through Tue. High
pressure will settle across the northern waters along 30N Wed
through Thu.

Farther east, latest scatterometer pass captured the presence of
a 1015 mb low pressure centered near 28N54W. Fresh to strong
winds are within about 90 nm on the southern semicircle of the
low center. A surface trough extends from 29N54W to the low to
near 21N59W. The same scatterometer pass indicates the wind
shift related to this trough. Seas of 9-11 ft in NE swell are
noted per an altimeter pass on the E side of the low and trough.
Convection is displaced to the NE of the low center affecting
mainly the waters just N of area between 44W-52W. A strong ridge
dominates the eastern Atlantic anchored by 1037 mb high pressure
located just N of the Azores. Divergence aloft east of a
mid/upper trough along 40W is supporting some shower activity
north of 20N and E of 38W. Scatterometer data depicts fresh to
strong winds along the southern periphery of the above mentioned
high pressure, and northeast of line roughly from the Cabo Verde
Islands to 31N42W. Seas are 8 to 13 ft northeast of this line as
well. Gentle to moderate trade winds and 5 to 8 ft seas are noted
elsewhere.

The Cumbre Vieja volcano, on the island of La Palma in the Canary
Islands, has been erupting since 19 September 2021. Low to medium
ash concentration is noted in the vicinity of the volcano drifting
towards the SW. 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/.

$$
ERA
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