[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 142239
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Dec 15 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 1800 UTC surface analysis and satellite imagery through
2220 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Sierra Leone near 07N12W
to 05N17W. The ITCZ continues from 05N17W to 06N35W to the coastal
border of French Guiana and Brazil near 04N51W. Scattered moderate
convection is noted from 03N-07N between 20W and 31W.

GULF OF MEXICO...

High pressure of 1031 mb located over over the southeast U.S.
extends a ridge across the entire Gulf of Mexico. A surface
trough is analyzed over the western Bay of Campeche. Low clouds
with embedded showers are associated with the trough. Moderate to
fresh NE winds prevail over the southeast Gulf with gentle to
moderate winds elsewhere. Seas are 4-6 ft over the southeast
Gulf, including the Yucatan Channel, 1-3 ft over the northeast
Gulf, and 3-5 ft elsewhere.

For the forecast, high pressure will prevail across the forecast
waters through the week. Fresh east winds will spread westward
through the Straits of Florida and into the eastern Gulf S of 26N
through midweek along with building seas. A cold front is forecast
to enter the basin by Sun bringing fresh to strong winds and
building seas across the NW Gulf.

CARIBBEAN SEA...

The pressure gradient from a 1031 mb high pressure centered over
the southeast U.S. combined with lower pressure over Colombia is
supporting fresh to strong easterly winds over the central
Caribbean, including the Windward Passage, south of Hispaniola,
and offshore Colombia. Fresh winds prevail across most of the
remainder of the basin. Seas are 7 to 8 ft over the south-central
Caribbean, and near the Cayman Islands based on a recent altimeter
pass. Seas of 5-7 ft prevail elsewhere. Scattered showers and
thunderstorms are noted over Nicaragua and regional waters.
Similar convection is also seen over the Gulf of Honduras. A
diffluent pattern aloft is helping to induce this convective
activity.

For the forecast, fresh to strong trades will prevail over the
central Caribbean through the end of the week. Moderate to fresh
trades are expected elsewhere. Strong high pressure will strengthen
over the western Atlantic through the forecast period. This will
result in fresh to locally strong northeast to east winds in the
Windward Passage, Mona Passage, the lee of Cuba, and south of
Hispaniola through the week.

ATLANTIC OCEAN...

The aforementioned high pressure located over the southeast U.S.
also dominates the SW N Atlantic producing moderate to fresh NE
to E winds S of 24N. Seas are 6-9 ft within this area of winds E
of the Bahamas based on altimeter data and buoy observations.
Patches of low level clouds with possible showers are E of
Florida to about 70W.

For the forecast west of 65W, high pressure will prevail across
the western Atlantic, supporting moderate to fresh winds over the
forecast waters. High pressure will build southward from the
middle to end of the week resulting in an increase in winds and
seas. This pattern will also increase winds and seas east of 65W
through the week.

Farther E, a cold front enters the Atlantic forecast waters near
31N48W and extends SW to near 28N56W. Isolated showers are
observed ahead of the frontal boundary. A 1026 mb high pressure
is situated over the Azores while a surface trough extends from a
low pressure located near the Madeira Islands across the Canary
Islands. The pressure gradient between the Azores high and lower
pressure within the monsoon trough and in the vicinity of the
ITCZ is supporting a large area of fresh to locally strong
easterly trade winds across the Atlantic from 13N to 24N with 8
to 10 ft seas.

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/. The latest advisory
states that eruption has weakened but is still ongoing. Ash plume
is drifting south-southeastward.

$$
GR
This weather bulletin was brought to you by:
www.nashvilleweather.net