[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231147
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
647 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 0600 UTC surface analysis and satellite imagery through
1000 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 30N90W-20N97W.
Expect N gale-force winds, from 21N to 27N 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 03N15W and 03N21W. The ITCZ continues from 03N21W to 04N30W
04N39W. Precipitation: isolated moderate to locally strong from
08N southward from 53W eastward.

Upper level SW wind flow is to the south of the line that runs
from 25N15W at the coast of Africa, to 22N23W, 17N30W 13N50Wand
11N58W.

...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 94W eastward.

A cold front has reached the NW corner of the Gulf of Mexico,
through the SW corner of Louisiana to the Deep South of Texas.
Please read the SPECIAL FEATURES section for details about gale-
force winds with the cold front. VFR conditions in the Texas
coastal plains, after the front passing through there. Broad
surface anticyclonic wind flow is in the Gulf of Mexico to the
east of the advancing cold front.

...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/IFR 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: VFR conditions in the Texas coastal plains, after the
passage of the cold front. LOUISIANA: IFR/LIFR and MVFR in the
southern third of the state, to the east of the cold front. VFR
behind the front. MISSISSIPPI: LIFR and heavy rain, in some areas,
from Natchez-to-Hattiesburg southward. ALABAMA: IFR/LIFR, from
Evergreen-to-Dothan southward. FLORIDA: MVFR in Crestview and
Tallahassee. LIFR from the Panama City metropolitan area to
Marianna, and from Perry to Cross City and Brooksville. IFR/LIFR
in the Tampa/St. Petersburg metropolitan area. LIFR from Sarasota
to Punta Gorda. MVFR in Fort Myers 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...

Middle level-to-upper level N-to-NE wind flow is moving across
Hispaniola. Large-scale anticyclonic wind flow is moving across
the Caribbean Sea 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: La Romana: MVFR. ceiling 1600 feet. Punta
Cana: light rain. MVFR. ceiling 1600 feet. MVFR in Santiago and
Puerto Plata. Low level clouds are moving from the Atlantic Ocean,
from 20N63W, to the coast of the Dominican Republic from 70W
eastward.

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 29N50W to 24N54W to 19N59W, and to
15N63W in eastern part of the Caribbean Sea. A surface trough is
along 31N51W 25N53W 19N59W. Precipitation: isolated moderate
within 30 nm to 60 nm on either side of 32N47W 27N51W 23N53W
21N57W 18N62W.

A stationary front passes through 32N59W to 31N60W. The
stationary front is dissipating from 31N60W to 30N64W and 29N69W.
A surface trough is along 31N54W 26N67W 26N75W. Rainshowers are
possible to the N of the line that passes through 32N50W 24N60W
23N79W.

An upper level trough extends from a 27N30W cyclonic circulation
center to 22N33W and 17N43W. No significant deep convective
precipitation is apparent in satellite imagery.

A surface ridge passes through 32N71W, to NW Cuba.

Surface anticyclonic wind flow covers the Atlantic Ocean from 20N
northward between Africa and 50W.

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

$$
MT
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