[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230556
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1256 AM EST Sat Dec 23 2017

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 0000 UTC surface analysis and satellite imagery through
0515 UTC.

...Gale Warning in the Gulf of Mexico...

Please read the latest NHC High Seas Forecast under AWIPS/WMO
headers MIAHSFAT2/FZNT02 KNHC for more details. for Saturday
morning: A cold front is forecast to be along 29N91.5W-23N97W.
Expect N gale-force winds, S OF 26N W of the front. The gale-
force wind conditions will continue until the late night hours of
Saturday night/early Sunday morning.

...ITCZ/MONSOON TROUGH...

The monsoon trough passes through the Prime Meridian along 05N,
to 02N16W and 04N21W. The ITCZ continues from 04N21W to 05N30W
04N41W 05N47W, and to NE Brazil near 04N51W. Precipitation:
isolated moderate to locally strong from 08N southward from 26W
eastward, and from 04N to 06N between 26W and 40W.

Upper level SW wind flow is to the south of the line that runs
from 26N14W at the coast of Africa, to 18N30W and 11N57W.

...DISCUSSION...

...THE GULF OF MEXICO...

Broad upper level anticyclonic wind flow spans the entire area,
from the SW corner, through the central Gulf of Mexico, beyond
Florida. Comparatively drier air in subsidence mostly covers the
area that is from 90W eastward. A stationary front/cold front is
in the eastern sections of Texas, from 31N95W, to a 1009 mb low
pressure center that is near 28N98W, to 27N99W, and to 26N102W in
Mexico.

Surface anticyclonic wind flow covers much of the Gulf of Mexico.
A ridge extends from a SE Georgia 1024 mb high pressure center,
to 28N86W 27N93W, to the Mexico coast near 22N98W.

...CURRENT CONDITIONS AND WEATHER, FOR THE OFFSHORE OIL PLATFORM
SITES, THAT ARE IN THE AREA WHOSE BOUNDARIES ARE FROM 27N
NORTHWARD AND FROM 88W WESTWARD...

MVFR conditions at many of the sites.

CURRENT CONDITIONS AND WEATHER, FOR THE COASTAL PLAINS OF THE
U.S.A., FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...

TEXAS: MVFR/IFR, light rain and drizzle, to the east of the
stationary front/cold front. LOUISIANA: MVFR/IFR/LIFR in the
southern third of the state. MISSISSIPPI: lIFR/IFR right at the
coast; MVFR from Natchez-to-Hattiesburg. ALABAMA: IFR/LIFR, from
Evergreen-to-Dothan southward. FLORIDA: LIFR/IFR from Tallahassee
westward. MVFR at the NE edge of the Tampa metropolitan area, and
in Naples.

...THE CARIBBEAN SEA...

A middle level to upper level anticyclonic circulation center is
about 90 nm to the WNW of the Cayman Islands. Comparatively drier
air in subsidence spans the entire Caribbean Sea.

Rainshowers are possible, in areas of broken low level clouds
that are spread across the entire Caribbean Sea.

24-hour rainfall totals in inches, for the period that ended at
23/0000 UTC, according to the PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.06 in
in Guadeloupe.

...HISPANIOLA...

Upper level northerly wind flow is moving across Hispaniola.
Large-scale anticyclonic wind flow is moving across the area at
the same time. Comparatively drier air in subsidence in water
vapor imagery covers Hispaniola.

SURFACE OBSERVATIONS...HAITI, in Port-au-Prince: VFR. in the
DOMINICAN REPUBLIC: Barahona: VFR, with few cumulonimbus clouds.
Puerto Plata: VFR. earlier rainshowers. VFR elsewhere.

The GFS MODEL forecast for 250 mb shows that NW wind flow will
move across the area, part of large-scale anticyclonic wind flow.
A SE-to-NW oriented trough will cover Hispaniola during the middle
part of day one. A Caribbean Sea ridge will push anticyclonic wind
flow across the area for the rest of the 48-hour forecast period.
The GFS MODEL forecast for 500 mb shows that NE wind flow will
move across the area during the next 2 days. An anticyclonic
circulation center will be in the Straits of Florida and NW Cuba.
The GFS MODEL forecast for 700 mb shows that large-scale NE wind
flow will move across the area. An inverted trough will move
westward across Hispaniola during the second half of day one.
Expect NE-to-E wind flow during day two.

...THE ATLANTIC OCEAN...

An upper level trough is along 32N51W to 24N54W to 19N60W, and to
16N63W in the NE corner of the Caribbean Sea. A surface trough is
along 32N51W 25N53W 19N59W. Precipitation: isolated moderate
within 90 nm on either side of 32N50W 27N51W 23N54W.

A stationary front passes through 32N58W to 31N61W. The stationary
front is dissipating from 31N61W to 26N67W 28N74W and 31N77W. A
surface trough is within 150 nm to the south of the front between
61W and 71W. Rainshowers are possible from 23N northward between
55W and 78W.

An upper level trough extends from a 25N35W cyclonic circulation
center to 17N40W and 12N43W. No significant deep convective
precipitation is apparent in satellite imagery.

Surface anticyclonic wind flow covers the Atlantic Ocean from 16N
northward between Africa and 50W.

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

$$
MT
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