[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230024
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
724 PM EST Sun Dec 22 2019

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2315 UTC.

...SPECIAL FEATURES...

NORTHEASTERN GULF OF MEXICO GALE WARNING...

A 1011 mb low is centered in the NE Gulf of Mexico near 29N86W.
Gale force winds are east of the low from 28N-29N between 84W-86W
with seas to 12 ft. Winds will decrease to below gale force this
evening at 23/0000 UTC.

SOUTHWESTERN GULF OF MEXICO GALE WARNING...

A tight pressure gradient between the aforementioned low pressure
and high pressure over Mexico is producing gale force winds in
the southwest corner of the Gulf of Mexico from 19N-22N between
92W-96W with seas to 13ft. The winds are forecast to decrease to
below gale force this evening at 23/0000 UTC.

WESTERN ATLANTIC OCEAN GALE WARNING...

Gale force winds are expected to begin this evening at 22/2100
UTC for the Atlantic waters offshore Georgia and northern
Florida, mainly north of 30N between 79W-81W. This is due to a
strong pressure gradient between the low pressure in the NE Gulf
of Mexico and a 1029 mb high pressure near 35N66W. The gale will
migrate slightly eastward by Monday evening, remaining north of
30N between 76W-79W. The gale is expected to end Monday night at
24/0600 UTC for the waters south of 31N.

For all three of the special features above, see the latest NWS
High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC
for further details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Sierra Leone
near 07N12W to 07N16W. The ITCZ continues from 07N16W to 04N21W to
02N37W to the coast of NE Brazil near 01N49W. Isolated moderate
convection is along the ITCZ from 01N-06N between 33W-49W.

GULF OF MEXICO...

Two Gale Warnings are over the Gulf of Mexico. See section above
for details.

A 1011 mb surface low is over the NE Gulf of Mexico near 29N86W.
A cold front extends southward from the low to 24N86W to the SE
Bay of Campeche near 19N92W. A warm front extends eastward from
the low to Jacksonville Florida near 31N81W. A prefrontal trough
is east of the front from 29N85W to the Yucatan Channel near
22N85W. Scattered moderate convection is over the E Gulf of Mexico
and Florida E of 90W.

In the upper levels, an upper level low is centered over Louisiana
near 31N91W supporting the surface frontal system. This upper
level low will move SE over the next several days and will be over
the W Atlantic near 27N71W Wed.

Winds and seas will diminish in the basin as the trailing cold
front sweeps southeast of the Gulf tonight and the low lifts
northeast toward the Georgia coast through late Mon. Weak high
pressure sets up in the wake of the front over the western Gulf
through mid week. Looking ahead, winds may increase over the
northeast Gulf by late Thu as a weak front approaches the region.

CARIBBEAN SEA...

A surface trough extends from the Yucatan Channel near 29N85W to
the NW Caribbean near 17N85W. Scattered showers are over the NW
Caribbean N of 16N and W of 83W. Scattered moderate convection is
also over W Cuba from 20N-23N between 80W-83W. In the far SW
Caribbean, the east Pacific monsoon trough is inducing scattered
moderate with isolated strong convection south of 11N and west of
76W, including over portions of Panama and southeastern Costa
Rica. The latest ASCAT pass shows fresh winds over the central
Caribbean, with strong winds in the south-central Caribbean.
GOES-16 low and mid-level water vapor channels show that dry air
covers the eastern and central Caribbean Sea. The dry air is due
to mid-level anticyclonic flow and sinking motion.

The Gulf of Mexico cold front will move through the Yucatan
Channel and into the far NW Caribbean tonight. The front will
reach from central Cuba to the Gulf of Honduras Mon morning, from
eastern Cuba to SE Nicaragua early Tue then stall and weaken from
the Windward Passage to Providencia Island through mid week. Fresh
to strong winds will follow the front over the western Caribbean.
Elsewhere, the front and its parent low pressure will shift into
the western Atlantic to the north of the area, displacing the
subtropical ridge and allowing moderate trade winds by mid to late
in the week.

Some coastal flooding is possible along the north coast of
western Cuba, including Havana, late Mon into early Tue, due to
the frontal System.

ATLANTIC OCEAN...

A 1012 mb low pressure in the NE Gulf of Mexico extends a
warm front to near Jacksonville Florida and just offshore the
Georgia coast. Widely scattered moderate convection is over the
Atlantic waters north of 26N and west of 69W. Gale force winds are
expected to begin this evening offshore of northern Florida and
Georgia. See section above for details.

A stationary front passes through 31N36W to 23N60W to 23N74W.
Scattered moderate convection is within 180 nm of the front. A
1028 mb high is centered over the E Atlantic near 35N15W.

Deepening low pressure currently just SE of Pensacola Florida
will move to the Georgia coast by Mon morning, with a trailing
cold front moving off the east coast of Florida. SE winds will
increase to gale force by late today off NE Florida ahead of the
approaching low and front. The front will continue to sweep
eastward, reaching from 31N72W to western Cuba by early Tue as the
low slowly moves toward 31N76W. The low pressure will weaken
little as moves toward 29N65W by early Wed, with the front
extending to the Windward Passage. Looking ahead, winds and seas
diminish across the region after late Wed as the low and front
move farther E and weaken.

$$
Formosa
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