[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301049
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Tue Nov 30 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 0600 UTC surface analysis and satellite imagery through
1030 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coastal border of Guinea
and Sierra Leone near 09.5N13W to 05N20W. The ITCZ continues from
05N20N to 03N25W to 01N45W. Scattered moderate convection is
evident from 04n to 06N between 30W and 40W.

GULF OF MEXICO...

1023 mb high pressure is centered over the lower Mississippi
Valley, following a cold front that move through the region
yesterday. A recent scatterometer satellite pass indicated fresh
winds off Veracruz. A concurrent altimeter pass indicated seas
there were about 6 to 7 feet. An earlier scatterometer satellite
pass showed fresh to strong winds near the Yucatan Channel,
following the cold front. These winds are diminishing, but 5 to 6
seas are likely near the Yucatan Channel at this time. Gentle to
moderate winds and 3 to 5 ft prevail elsewhere. The pattern
remains fairly dry following the front, with no showers,
thunderstorms or fog noted anywhere over the Gulf currently.

For the forecast, high pressure is building across the northern
Gulf and will dominate the basin the remainder of the week. As
high pressure moves eastward, southerly return flow will set-up
across the northwest Gulf by mid-week.

CARIBBEAN SEA...Updated

The combination of the convergence of northeast trades with
divergent flow aloft present east of an upper-level trough that is
along the coast of Nicaragua is resulting in clusters of showers
and thunderstorms within 60 nm of the coasts of Panama and Costa
Rica. No significant showers or thunderstorms are noted elsewhere.
A shear line extends from central Cuba to near Cozumel off the
Yucatan Peninsula. An earlier scatterometer satellite pass
indicated fresh to strong winds across the Yucatan Channel, north
of this line. These winds are diminishing, but at least fresh
winds and seas to six feet can be expected during the early
morning hours before winds and seas subside later in the morning.
Fresh to strong winds are also pulsing off the coast of Colombia.
A recent altimeter satellite pass showed seas to 7 ft just west of
the area of maximum winds off the coast between Cartagena and
Barranquilla, where seas to 8 ft are likely. Fresh N winds are
possible along the coast of Nicaragua as well, although shallow
waters limit wave growth in that area. Moderate to fresh NE winds
are possible in the lee of Cuba, but these winds are diminishing
quickly. Outside of the Yucatan Channel and the lee of Cuba, light
breezes and slight seas are noted across the northwest Caribbean.
Moderate to fresh trade winds and 4 to 6 ft seas are evident
elsewhere.

For the forecast, the shear line extending from central Cuba to
Cozumel will dissipate later today. Fresh to strong NE winds
following the front over the Yucatan Channel will diminish later
today. Elsewhere, high pressure north of the area will maintain
moderate to fresh NE to E winds across the Caribbean through the
week, with strong winds pulsing off Colombia, mainly at night.

ATLANTIC OCEAN...

As of 03Z, a cold front extends from 31N62W through the central
Bahamas, with a dissipating portion extending to central Cuba. A
trough extends west of the front from near 31N66W to 25N78W, near
Andros Island in the Bahamas. A pre-frontal trough was also
analyzed east of the front from 28N62W to 21N70W. Scattered
showers are noted north of 29N within 60 nm east of the front.
Scattered showers and thunderstorms are noted from 25N to 28N
between 56W and 61W. Earlier scatterometer satellite data showed
strong southwest winds within 180 nm east of the front north of
28N, and fresh to strong south to southwest winds elsewhere within
east of front to 55W and north of 25N. The scatterometer data
also depicted fresh northwest winds within about 60 nm west of the
front and north of 29N. Seas of 8 ft are present within the area
of strong winds.

Over the Central Atlantic, a trough extends from near 29N42W to
22N45W. Divergence aloft associated with a mid/upper trough in
this area is supporting clusters of moderate convection north of
22N between the trough and 37W. A strong 1036 mb high pressure
center near the Azores and lower pressures over western Africa
allow for a moderate pressure gradient, resulting in a large area
of fresh to strong anticyclonic winds east of 40W and north of
05N. The strongest winds are occurring east of 30W and north of
14N, including the waters surrounding the Canary Islands. Seas of
8-12 ft are present east of 45W, with the highest seas occurring
north of the Cabo Verde Islands. Elsewhere, fairly tranquil
weather conditions, moderate or weaker winds and seas of 5-8 ft
prevail.

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 west of 65W, the previously-mentioned cold front
will extending from 31N62W to central Cuba will stall from 31N57W
to eastern Cuba through tonight, then dissipate through mid week.
High pressure will settle across the forecast area in the wake of
the front, and dominate the region through Sat.

$$
Christensen
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