[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210007
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
707 PM EST Thu Dec 20 2018

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
2345 UTC.

...SPECIAL FEATURES...

...GALE WARNING GULF OF MEXICO...

A large area of gale force wind is expected to develop in the
Gulf of Mexico this afternoon along and behind a vigorous cold
front. Strong to gale force winds will progress eastward through
the Gulf by Fri evening. Areas north of 23N between 81W-95W are
forecast to experience gale force winds. Seas across portions of
the central Gulf will build to 14 ft by this afternoon and as high
as 21 feet tonight and Friday.

...GALE WARNING ATLANTIC OCEAN...

S to SW gale force winds are expected in the western Atlantic in
advance of a cold front. The area of gales will expand tonight
into early Fri as the cold front progress eastward through the
waters.

Please read the HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...for
more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through southern Liberia near 04N08W to
03N13W. The ITCZ continues from that point to 01N29W to 02N41W.
Scattered moderate convection is observed from 03N to 00N between
35W-45W. Elsewhere, scattered showers are noted along and within
the ITCZ and monsoon trough.

GULF OF MEXICO...

A cold front extends from a 997 mb low pressure center at 30N87W
to 26N87W in the central part of the Gulf of Mexico. Then, enters
the Yucatan peninsula near 21N88W and continues into Mexico. A
pre-frontal surface trough is within 180 nm to 200 nm to the east
of the cold front. Most of the stronger convection is associated
with this pre-frontal trough. Numerous moderate isolated strong
convection runs right along the pre-frontal surface trough from
31N80W to Fort Myers near 26N82W to the western coast of Cuba near
20N86W. Broken to overcast multilayered clouds and other possible
scattered thunderstorms are seen in the vicinity of the cold
front. A second surface trough is also observed west of the cold
front from 29N90W to 24N91W. Scattered convection is noted 60 to
90 nm west of this surface trough.

The strong cold front will move E across the eastern gulf waters
overnight preceded by lines of tstms and followed by large seas.
Strong to gale force winds will spread E across the entire Gulf of
Mexico overnight, then diminish from the W with the gale conditions
diminishing across the Straits of Florida late Fri. Seas are
forecast to subside to less than 8 ft by late Sat. High pres will
shift eastward across the central gulf on Sat, then move across
the Florida Panhandle on Sun leaving a ridge from the Florida Big
Bend to Se Texas on Mon. Fresh return flow will set up across the
NW waters on Tue.

CARIBBEAN SEA...

A pre-frontal surface trough extends 180 to 200 nm to the east of
a cold front over the Gulf of Mexico. The tail end of the trough
enters the western Caribbean waters from western Cuba to the
Yucatan peninsula. Scattered modearte isolated strong convection
is noted from 22N82W to 20N84W. Observation in Habana registered
wind gust near 50 knots ahead of the surface trough.

An upper level ridge extends from northeast Bahamas to Colombia
and NW Venezuela. Scatterometer data depicts moderate to fresh
winds south of Jamaica into NW Colombia. Convection is very
limited as upper level ridge remains in control. Scattered
showers are noted along the coast of northwest portion of Colombia
into Panama and Costa Rica. Most of these showers are associated
with the surface trough extending into the Pacific.

Fresh to locally strong winds will continue across the south-
central Caribbean through Tue, increasing to near gale force along
the NW coast of Colombia during the overnight hours. Strong
southerly flow will continue over the NW Caribbean ahead of a cold
front entering the Yucatan Channel overnight. The front will
reach from the Windward Passage to Costa Rica by Sat morning, then
drift S and gradually dissipate through Sun. Strong northerly
winds are expected W of the front on Fri and Fri night, increasing
to near gale force along the coast of Nicaragua.

ATLANTIC OCEAN...

A cold front passes through 32N38W transitions to stationary front
near 31N42W to 24N60W to 26N69W. Scattered moderate convection
from 32N38W to 26N39W. Scattered convection is also observed from
26N to 16N between 20W-33W.

One surface trough is along 44W/43W from 23N to 14N. Rainshowers
are possible along the vicinity of the trough. A second surface
trough is along 51W/53W from 23N to 10N. Rainshowers are possible
within the the vicinity of the trough.

Near gale to gale force southerly flow is developing W of 75W and
N of 27N to the E of 75W ahead of a strong cold front moving off
the the SE United States coast preceded by lines of tstms. The
cold front will reach from near 30N75W to west- central Cuba early
Fri, from 30N72W to eastern Cuba on Fri evening, weaken from
Bermuda to the Windward Passage on Sat, then become stationary
from 27N65W to eastern Cuba on Sun. Winds and seas will diminish
across the region Sat and Sun.

For additional information please visit
http://www.hurricanes.gov/marine

$$
MTorres
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