[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220014 CCA
TWDAT

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
0005 UTC Mon Nov 22 2021

Corrected to include latest information on the Cumbre Vieja
volcano

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
2345 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: A strong cold front is forecast to
reach from near Bermuda to eastern Cuba by late Tue. Fresh to
strong winds and building seas are expected on either side of the
front beginning on Tue. North gale-force winds are expected
north of 30N and just west of the front by late Tue. Seas are
forecast to build to 10-15 ft with these winds. Please refer to
the latest High Seas Forecast issued by the National Hurricane
Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml
for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis passes through the coastal plains of
Guinea-Bissau near 12N16W and continues southwestward to
09N20W, where latest scatterometer data indicates that
it transitions to the ITCZ to 06N30W to 06N38W to 06N45W,
and northwest to 10N49W to 11N54W and to the coast of
Venezuela at 09N61W. Scattered moderate to isolated strong
convection is within 60 nm south of the ITCZ between 30W-34W,
and within 60 nm north of the ITCZ between 34W-37W. Scattered
moderate convection is within 60 nm north of the ITCZ between
27W-29W.

GULF OF MEXICO...

High pressure ridging extends from a 1026 mb high that is
located over northern Georgia southwestward to over southeastern
Louisiana and to near 25N95W. Latest ASCAT data shows generally
light to gentle northeast to east winds over the western half
of the Gulf, and gentle to moderate northeast to east winds
over the eastern half. Seas are in the 2-4 ft range, with
the exception of the slightly higher seas of 3-5 ft over
the eastern half of the Gulf.

For the forecast, the aforementioned high pressure will
gradually shift eastward tonight into Mon in response to
a large upper-level trough that is over the mid-west
section of the United States. This trough will drive a strong
cold front over the NW Gulf early on Mon. The cold front will
quickly move southeastward and exit the Gulf region by Mon
evening. Fresh to strong northerly wind will be expected behind
the front, mainly over the eastern and southern Gulf near
Veracruz, Mexico late Mon into Tue. High pressure is forecast
to build in behind the front. Fresh southerly return flow will
set up across the NW Gulf by the middle of the week ahead of the
next cold front forecast to reach the Gulf waters by Thu night.

CARIBBEAN SEA...

Broad-upper level anticyclonic wind flow covers the entire
Caribbean Sea per upper-level wind data. Water vapor imagery
depicts subsidence and resultant in rather stable atmospheric
conditions over the central and eastern Caribbean, with only
shallow moisture evident there. The GOES-E satellite imagery
animation shows a surface disturbance near 70W. This feature
has been tracking westward all day. Scattered showers are
possible south of 15N between 67W-70W. Latest ASCAT pass over
this feature indicates a northeast to southeast wind shift
across it, with winds of gentle to moderate speeds. The
eastern segment of the E Pacific monsoon trough extends eastward
to just inland the coast northwestern Colombia. Scattered
showers and isolated thunderstorms are confined to the
southwestern Caribbean waters south of about 14N and west of
79W to Central America and over northern Colombia, where the
activity is increasing. Isolated showers are possible elsewhere
west of 78W. The latest ASCAT data also indicates gentle to
moderate trades over just about the entire basin, except south
of 15N and east of 80W where stronger trades of fresh speeds are
present. Seas are in the range of 2-4 ft, except for slighter
higher seas of 3-5 ft from 11N to 15N west of 72W.

For the forecast, the gentle to moderate trades will continue
across most of the basin through Mon night. A cold front will
reach the Yucatan Channel by Mon evening, and extend from eastern
Cuba to the Gulf of Honduras by Tue evening. Fresh to locally
strong winds and building seas are expected across the western
Caribbean, the Windward Passage and Mona Passage likely through
Thu as high pressure builds to the north of the area in the wake
of the front.

ATLANTIC OCEAN...Corrected

Please see the Special Features section above for details
regarding an upcoming gale event.

A shear line extends from near 31N56W to 28N68W and to just
east of Stuart, Florida. Recent ASCAT data shows fresh to
strong northeast to east winds north of this feature. Seas
with these winds are in the 8-10 ft range. Scattered showers
are within 120 nm north of the shear line between 71W-74W and
between 77W-80W. Gentle to moderate east winds are south
of the shear line.

Upper-level cyclonic wind flow covers the Atlantic Ocean from
15N northward from 40W eastward. The large upper-level trough
that is in this area is sustaining a cold front that extends from
31N32W to 23N35W to 21N46W and to 21N56W. A trough is about 225
nm to 350 nm to the SSE of the cold front. A post-frontal trough
is about 150 nm to 270 nm to the northwest and north of the cold
front. Broken to overcast multilayer clouds along with isolated
showers and thunderstorms are seen from 10N to 15N between 40W
and 60W, and north of 20N between Africa and the first surface
trough. Similar activity is north of 20N between the cold front
and 65W. Seas range from 8-12 ft north of 23N between 30W-40W.
Seas range from 3-4 ft from the Cabo Verde Islands northward
between Africa and the first surface trough. Seas range from
4-6 ft elsewhere south of 20N and east of 60W. Fresh to strong
winds are from 27N northward between 15W and 43W. The wind
speeds are moderate or slower elsewhere south of 20N and east
of 60W.

The Cumbre Vieja volcano, on the island of La Palma in the
Canary Islands, has been erupting since 19 September 2021.
Medium ash concentration is in the vicinity of the volcano,
while lower concentration is elsewhere. 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, the shear line will remain over the northern
forecast waters through tonight, before lifting north as warm
front ahead of a strong cold front that will move off the
northeast Florida coast on Mon. The next cold front will reach
from near Bermuda to eastern Cuba late on Tue. Fresh to strong
winds and building seas are expected on either side of the front
beginning on Tue. Gale force winds are expected north of 30N and
just west of the front by late Tue.

$$
Aguirre
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