[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281746
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sun Nov 28 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
1700 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coastline of Guinea near
10N14W to 05N19W. The intertropical convergence zone continues
from 05N19W to 03N35W to 01N50W. Scattered moderate convection is
noted from 03N to 07N between 25W and 31W.

GULF OF MEXICO...

A stationary front extends from the SE Gulf near 24N84W to a 1015
mb surface low centered off the Texas coast near 27N94W. A cold
front stretches from the low center to near Tampico, Mexico.
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. Abundant
cloudiness with embedded showers is noted over the northern Gulf
and also W of the cold front. A surface trough is analyzed just W
of the Yucatan peninsula extends from 22N91W to 18N92W.

For the forecast, the low pressure will move into the southeast
Gulf through tonight then dissipate along with the front, ahead of
another cold front expected to enter the northeast Gulf this evening.
The second front will move across the eastern Gulf through Tue night,
allowing high pressure to build over the northern Gulf through Thu.
Fresh to strong winds and building seas to 8-9 ft are expected in
association with the low.

CARIBBEAN SEA...

Weak high pressure located N of the Caribbean Sea 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 12N66W. 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. Moderate N to NE swell
will continue across the Atlantic waters east of 70W and through
the NE Caribbean passages through late tonight into Mon. Looking
ahead, a weak cold front will move into the northwest Caribbean
Mon night, then stall and dissipate Tue night through Wed. High
pressure north of the front will induce strong trade winds across
the south central Caribbean Tue night through Thu night.

ATLANTIC OCEAN...

A cold front enters the Atlantic forecast area near 31N65W and
continues SW to the NW Bahamas. Mainly light winds are seen 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 later today into tonight building seas
to 4-7 ft, highest E f 70W.

For the forecast west of 65W, a reinforcing cold front will move
off northeast Florida late today, reach from Bermuda to southeast
Florida by late Mon, then start to 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.

Farther east, a recent scatterometer pass captured the presence of
a 1015 mb low pressure centered near 27N54W. Fresh to strong
winds are within about 90 nm on the southern semicircle of the low
center. A surface trough extends from the low to near 30N52W. The
same scatterometer pass indicates the wind shift related to this
trough. Another trough stretches southward from the low center to
near 22N53W. Seas of 9-11 ft in NE swell are noted per an altimeter
pass on the E side of the low and troughs. Convection is displaced
to the NE of the low center affecting mainly the waters just N of
area between 48W-53W. A strong ridge dominates the eastern
Atlantic anchored by 1038 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 27N between 35W and 40W.
A surface trough is embedded within this area along 39W/40W N of
22N. Scatterometer data show 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/.

$$
GR
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