[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172318
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
618 PM EST Sun Dec 17 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 1800 UTC surface analysis and satellite imagery through
2245 UTC.

...SPECIAL FEATURES...

...Gale Warning in the Caribbean Sea...

NE-to-E gale-force winds will start again during the early
morning hours of Monday, in about 12 hours, from 11N to 13N
between 73W and 76W, in the waters that are off the coast of
Colombia. Expect sea heights to range from 10 feet to 15 feet. The
wind speeds will be less than gale-force by Monday afternoon. The
gale-force NE-to-E winds will start again during the early morning
hours of Tuesday, and eventually be continuing at gale-force
again by Tuesday afternoon. Please read the latest NHC High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more
details.

...ITCZ/MONSOON TROUGH...
The monsoon trough passes through the coastal sections of Sierra
Leone near 07N12W, to 07N20W and 06N26W. The ITCZ continues from
06N26W to 05N29W, 07N42W, and to 06N46W. Precipitation: isolated
moderate within 240 nm on either side of 10N36W 06N41W 03N51W.

An upper level trough is along 31N35W 24N35W 20N38W 12N45W 07N50W
04N54W. Broken-to-overcast multilayered clouds and possible
rainshowers are within 480 nm to the SE of the 31N35W-to-04N54W
line.

...DISCUSSION...

THE GULF OF MEXICO...

A cold front extends from a SW Louisiana 1018 mb low pressure
center, to 28N92W and 25N94W. A stationary front continues from
25N94W, to the coast of Mexico near 21N97W. Scattered moderate to
strong rainshowers are from 27N to 29N between 89W and 91W, in the
waters that are off the coast of SE Louisiana.

A surface ridge passes through Florida near 29N81W, to 24N86W in
the SE corner of the Gulf of Mexico, to Honduras.

...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...

Mostly MVFR, and a few cases of IFR, at the platforms.

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

TEXAS: MVFR in the Deep South/the Lower Valley. IFR from the
Middle Texas Gulf coast toward Laredo. LOUISIANA: IFR/LIFR from
Baton Rouge-to-Patterson east and southeastward. LIFR, light rain,
and fog in Boothville. MISSISSIPPI: IFR/LIFR, with rain and fog,
from Natchez-to-Hattiesburg southward. ALABAMA: IFR in Evergreen
and in Dothan. IFR/LIFR from Mobile to Gulf Shores, and areas of
rain. FLORIDA: IFR/LIFR and rain in the Florida Panhandle. MVFR in
parts of the Pensacola metropolitan area.

THE CARIBBEAN SEA...

Broad middle level-to-upper level anticyclonic wind flow, and
comparatively drier air in subsidence, span the entire Caribbean
Sea.

Rainshowers are possible in areas of broken low level clouds, from
70W eastward, from 11N to 18N between 70W and 80W, and from 80W
westward.

Please refer to the SPECIAL FEATURES section for more details
about the gale-force winds for the coast of Colombia during the
next two days.

24-hour rainfall totals in inches, for the period that ended at
17/1200 UTC, according to the PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.18 in
Curacao, 0.10 in St. Thomas in the Virgin Islands, 0.08 in San
Juan in Puerto Rico, 0.06 in Guadeloupe, 0.04 in Montego
Bay in Jamaica, 0.02 in Trinidad, and a TRACE in Freeport in the
Bahamas.

...HISPANIOLA...

Upper level N-to-NW wind flow is moving across Hispaniola. NE-to-E
wind flow from 400 mb to 800 mb also is present across the island.
Broad middle level-to-upper level anticyclonic wind flow spans
the entire Caribbean Sea.

SURFACE OBSERVATIONS...HAITI, in Port-au-Prince: VFR. in the
DOMINICAN REPUBLIC: VFR at all the observation sites.

The GFS MODEL forecast for 250 mb shows that Hispaniola will be to
the east of a ridge. Expect N-to-NW wind flow during the next 48
hours. 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 move from the Bahamas near Andros Island
toward NW Cuba. The GFS MODEL forecast for 700 mb shows that NE
wind flow will move across the area. An anticyclonic circulation
center will be in the area from the NW Bahamas to the Straits of
Florida.

THE ATLANTIC OCEAN...

A deep layer central Atlantic Ocean trough is supporting a cold
front, that passes through 32N48W to 25N60W and 24N65W. The cold
front is dissipating from 24N65W and 23N73W. Precipitation:
scattered moderate to strong rainshowers are from 31N to 33N
between 42W and 44W. rainshowers are possible elsewhere within 180
nm on either side of the line that passes through 32N40W to 29N46W
to 26N51W to 24N55W, and elsewhere from 20N northward from 55W
westward. This cold front is ready to merge with a cold front
that passes through 32N45W to 31N47W.

A surface ridge passes through 32N29W to 25N42W and to 23N55W.

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

$$
MT
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