[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 100445
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Fri Dec 10 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
0444 UTC.

...SPECIAL FEATURES...

East Atlantic Gale Warning: A robust high pressure system of 1035
mb continues anchored near the Azores. This system is producing a
tight pressure gradient off the coast of Morocco, generating N-NE
gales in the marine zone of Agadir. The winds are forecast to
decrease below gale-force later this morning. Expect seas of
10-14 ft within the area of gale force winds, subsiding to 7-10 ft
this afternoon. Please read the latest High Seas Forecast issued
by Meteo France at website http://weather.gmdss.org/II.html for
more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough remains mostly confined to the African
continent, reaching the coast of Guinea near 09N13W and extending
to 07N18W. The ITCZ then continues from 07N18W to 03N36W. A
surface trough then interrupts the ITCZ, located along 39W, from
01N to 08N. The ITCZ resumes near 02N40W to 01N50W. Scattered
moderate to isolated strong convection is noted from 01N to 11N
and between 22W and 50W.

GULF OF MEXICO...

A broad ridge extends from the Mid-Atlantic states to the Gulf of
Mexico. A dry continental airmass continues to suppress the
development of showers and thunderstorms across the region,
allowing for tranquil weather conditions. Recent scatterometer
satellite data and surface observations indicate that moderate to
locally fresh SE-S winds are present W of 90W, while weaker winds
are noted elsewhere in the basin. Seas of 2-4 ft are occurring in
the Gulf, with the highest seas prevailing in its northwestern
waters.

For the forecast, the aforementioned ridge will gradually shift
eastward through Sat afternoon in response to a strong cold front
that will move over the NW Gulf by early Sat. Moderate to fresh
southerly return flow will set-up across the western and central
Gulf beginning tonight and through Sat ahead of the strong cold
front. Fresh to strong northerly winds and building seas are
expected in the wake of the front through late Sat night. The
front will weaken as it reaches from central Florida to the SW
Gulf Sun and dissipate by Mon evening. Fresh to strong east winds
will spread westward through the Straits of Florida and to the
eastern Gulf S of 26N Mon through Tue night along with building
seas.

CARIBBEAN SEA...

The tight pressure gradient as a result of the strong ridge north
of the Greater Antilles and lower pressures over northern South
America is causing strong to near gale-force trades in the south-
central Caribbean, with the strongest winds occurring off the
coast of NW Colombia. Fresh to locally strong trades are noted in
the north-central Caribbean and moderate to fresh trades
elsewhere in the basin. Seas of 5-8 ft are prevalent in the
central Caribbean, with the highest seas occurring off NW
Colombia. Seas of 2-5 ft prevail in the rest of the basin.
Tranquil weather conditions continue across the Caribbean Sea due
to very dry atmospheric conditions limiting the formation of
convection.

For the forecast, the aforementioned pressure gradient will
continue to support fresh to strong trades over the south- central
Caribbean and in the Gulf of Venezuela through Fri night.
Moderate to fresh trades will prevail elsewhere. High pressure
will begin to strengthen over the western Atlantic tonight
resulting in fresh to locally strong northeast winds to develop in
the Windward Passage, the lee of Cuba and south of Hispaniola
through Tue night.

ATLANTIC OCEAN...

A weak stationary front extends from 31N62W to the Space Coast of
Florida near 28N80W. Meanwhile, a pre-frontal trough stretches
from 31N58W to 27N67W and only isolated showers are present near
these boundaries. A recent scatterometer satellite pass show
moderate to locally fresh NE winds behind the frontal boundary. In
general, winds W of 60W are moderate or weaker. Seas of 4-7 ft
prevail W of 60W.

A broad surface trough is located along 49W, from 14N to 26N, and
it is producing a few showers near the trough axis. The rest of
the tropical Atlantic is dominated by the robust Azores high,
resulting a fairly tranquil weather conditions. Satellite-derived
wind data depict fresh to strong easterly winds N of 05N and E of
55W. The strongest winds are confined to E of 33W and N of 16N.
Seas of 8-11 ft are found E of 48W, while seas of 5-8 ft are found
elsewhere in the basin.

For the forecast west of 65W, a stationary front extends from
31N62W to 28N80W. The front will dissipate through the next 24
hours. High pressure will build across the region in the wake of
the front, producing moderate to fresh NE to E winds S of 22N, and
mainly gentle to moderate winds N of 22N through Sat night. The
next cold front will move off the northeast Florida coast early on
Sun, and reach from near 31N65W to South florida by Sun night.
This front is forecast to dissipate over the southeastern waters
on Mon. High pressure behind the front will likely bring fresh to
strong northeast to east winds mainly across the waters south of
27N by Mon night. These conditions are expected to last through
Tue night.

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/.

$$
DELGADO
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