[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190507
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Fri Nov 19 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
0455 UTC.

...SPECIAL FEATURES...

Gulf of Mexico Gale Warning: A cold front extends from SE
Louisiana to Tamaulipas, Mexico. Gale-force NW-N winds are
forecast to develop offshore of Veracruz this afternoon as strong
high pressure strengthens behind the front. Peak seas of around
12 ft are expected with the gale-force winds. Winds in the region are
forecast to diminish to below gale-force late tonight as the high
pressure shifts eastward allowing the pressure gradient to
slacken. The cold front will reach the SE Gulf this weekend,
becoming stationary from near Naples, Florida to the Bay of
Campeche. Please see the latest NWS High Seas Forecast issued by
the National Hurricane Center at
website://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more
information.

...MONSOON TROUGH/ITCZ...

The monsoon trough remains mostly confined to the African
continent. It reaches the Atlantic through the coast of Guinea-
Bissau near 12N16W and extends to 08N17W. The ITCZ then continues
from 08N17W to 05N25W to 07N36W. A surface trough is just west of
the ITCZ along a position from near 09N39W to 03N44W. The ITCZ
resumes near 06N45W to 04N51W. Scattered moderate to isolated
strong convection is found from 03N to 16N and E of 46W.

GULF OF MEXICO...

Please see the Special Features section above for details on a
Gale Warning that is in effect for waters near Veracruz, Mexico.

A cold front continues to move across the NW Gulf of Mexico,
extending from SE Louisiana to Tamaulipas. Scattered moderate
convection is noted in the W Gulf, mainly from 22N to 27N and W of
95W. Recent scatterometer satellite data and surface observations
show strong to near-gale force NE winds behind the frontal
boundary. The strongest winds are occurring within 100 nm of the
Texas and SW Louisiana coasts. Seas of 6-9 ft are also found in
the described area, with the highest seas occurring off Tampico.

Plenty of tropical moisture ahead of the front and divergence
aloft result in a large area of cloudiness and widespread shallow
showers affecting most of the Gulf, especially E of 90W.
Satellite-derived wind data depict fresh to strong NE winds N of
21N and the cold front and W of 87W. Moderate or weaker winds
prevail elsewhere. Seas of 3-6 ft are found in the SE Gulf and
Bay of Campeche, while seas of 1-3 ft are prevalent in the NE
Gulf.

For the forecast, the aforementioned front will continue to move
across the northern and western Gulf through Fri, then stall from
near Naples, Florida, to the Bay of Campeche this weekend, before
dissipating. Strong winds, with frequent gusts to gale force, and
rough seas follow the front. Winds are expected to reach gale
force off Veracruz, Mexico on Fri. Looking ahead, another cold
front will move into the northwest Gulf early Mon, and move south
of the basin Tue. High pressure will build over the northern Gulf
in the wake of the front.

CARIBBEAN SEA...

The favorable upper level dynamics that led to multiple days of
unsettled weather in the NW Caribbean Sea have shifted northward,
allowing for a much drier weather pattern to return to the region.
A surface trough extends from the SE Gulf to Guatemala and
divergence aloft is enhancing the development of convection in the
area, with a couple of showers spilling over into the Caribbean
waters off NE Yucatan. A few showers are also present in the SW
Caribbean, mainly within 100 nm of the coast of Nicaragua. The
rest of the basin enjoys fairly tranquil weather conditions.

A recent scatterometer satellite pass show fresh to locally strong
trades in the central and NE Caribbean Sea, with the strongest
winds occurring offshore NW Colombia. Strong trades are also
noted within 100 nm to the south of Hispaniola. Moderate or
weaker trades prevail elsewhere. Seas of 4-7 ft are found in the
SW, central and E Caribbean, while 2-4 ft are prevalent in the
rest of the basin.

For the forecast, fresh to locally strong NE winds persist in a
broad swath from the northeast Caribbean into the southwest
Caribbean. Winds and seas will diminish through Fri as high
pressure north of the area shifts east, ahead of a cold front
moving into the Gulf of Mexico and western Atlantic. Winds and
seas will further diminish early next week, ahead of a stronger
cold front moving through the Gulf of Mexico Mon. The stronger
front will reach the Yucatan Channel by late Mon night and extend
from eastern Cuba to the Gulf of Honduras by late Tue.

ATLANTIC OCEAN...

A large area of showers and isolated thunderstorms affects the
western tropical Atlantic, mainly N of 24N and W of 74W. This is
associated with a surface trough that extends from 24N to 30N
along 80W and divergence aloft thanks to the upper level trough
that covers most of the eastern United States. A recent
scatterometer satellite pass show fresh to locally strong cyclonic
winds across the NW Bahamas and off SE Florida, likely associated
with the storms in the area.

Farther east, a cold front enters the basin near 31N42W and
quickly transitions into a shear line near 30N44W that stretches
southwestward to near the central Bahamas. Isolated showers are
noted near the shear line. Satellite-derived wind data indicate
that fresh to strong NE-E winds are found behind the shear line.
Fresh NE-E winds are noted between the shear line the islands of
the NE Caribbean Sea. Seas of 6-10 ft are found W of the shear
line, with peak seas higher than 8 ft occurring N of 25N and
between 44W and 57W.

A weak surface trough is located 300 nm E of the Leeward Islands
along 57W and a few showers are observed east of the trough axis.
Farther east, a weakening surface trough extends from 26N34W to
23N33W to 16N42W and the trough is devoid of any significant
convection. The rest of the basin enjoys fairly tranquil weather
conditions, with moderate or weaker winds and seas of 3-6 ft.

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/.

For the forecast, a shear line extends from 22N65W into the central
Bahamas. Fresh to strong NE to E winds and rough seas are evident
a couple of hundred miles to the north of this line. The shear
line will dissipate through tonight in advance of a cold front
that will move off the NE Florida coast Fri. The front will stall
along roughly 28N this weekend, before lifting north ahead of a
strong cold front that will move off the northeast Florida coast
Mon. The second front will reach from Bermuda to eastern Cuba by
late Tue.

$$
DELGADO
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