[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081156
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
656 AM EST Fri Dec 8 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
1115 UTC.

...SPECIAL FEATURES...

...GALE-FORCE WINDS IN THE GULF OF MEXICO...

A stationary front is along 31N76W in the Atlantic Ocean,
through central Florida near 28N82W, to 25N90W, to a 1010 mb low
pressure center that is near 24N92W. The stationary front
continues from the 1010 mb low pressure center, to the Isthmus of
Tehuantepec of southern Mexico. Expect N-to-NE gale-force winds
and sea heights ranging from 8 feet to 16 feet, within 90 nm of
the line from 29N93W to 26N95W. Gale-force winds are being
forecast with respect to the frontal boundary, during the next
42 hours. Please read the latest NWS High Seas Forecast under
AWIPS/WMO headers MIAHSFAT2/FZNT02 for more details.

Upper level SW wind flow spans the entire Gulf of Mexico. Upper
level moisture is moving from the Yucatan Channel across the
southern half of Florida. Upper level moisture also is from 25N
northward. Precipitation: isolated moderate rainshowers are
in the Gulf of Mexico.

...ITCZ/MONSOON TROUGH...
The monsoon trough passes through the coastal sections of Sierra
Leone near 08N13W, to 06N20W. The ITCZ continues from 06N20W to
03N32W and 03N43W. Precipitation: widely scattered moderate to
isolated strong rainshowers within 120 nm on either side of the
line from 03N01W to 03N12W to 04N20W and 05N30W. Rainshowers are
possible elsewhere from 10N southward between 30W and 60W.

A surface trough is along 42W/43W from 05N to 11N. rainshowers
are possible within 60 nm on either side of the trough.

...DISCUSSION...

THE GULF OF MEXICO...

Please read the SPECIAL FEATURES section for information about the
current cold front, that passes through NE Florida, into the west
central Gulf of Mexico, to the Mexico coast near 20N98W.

...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, and some IFR conditions, at the platform sites.

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

CONDITIONS WITH THE CURRENT GULF OF MEXICO FRONT BOUNDARY:
IFR/MVFR, and snow and light rain, from the Deep South of Texas
to Mississippi. IFR/MVFR and light rain from Alabama to
Tallahassee in Florida. from Perry Florida to Naples: LIFR/IFR and
mist.

THE CARIBBEAN SEA...

An upper level ridge extends from N Colombia to the NW part of
Cuba.

One surface trough is along 17N83W 14N81W 12N80W, in the area of
the offshore waters of Honduras and Nicaragua. Precipitation:
scattered moderate to strong rainshowers from 11N to 13N between
81W and 83W. isolated moderate to locally strong elsewhere from
11N northward between 80W and 84W.

A second surface trough is in the NW corner of the Caribbean
Sea, from the NW tip of Cuba to the W coastal sections of
Honduras. Precipitation: isolated moderate rainshowers from 84W
westward in the NW corner of the area.

The monsoon trough is along 10N between 74W in Colombia and
85W/86W in western sections of Costa Rica. 10N80W, beyond
southern Nicaragua. Precipitation: isolated moderate to locally
strong rainshowers from 13N southward between 76W and 82W.

Isolated moderate rainshowers cover the Caribbean Sea from the
Greater Antilles southward, from 72W eastward. This precipitation
is related to remnant atmospheric instability, from an already-
dissipated frontal boundary of the last few days, that has moved
into the area from the Atlantic Ocean. A surface trough also is
along 16N54W in the Atlantic Ocean, to 15N60W, and to 16N65W in
the eastern Caribbean Sea.

...HISPANIOLA...

Upper level SW wind flow is moving across the area. Broad upper
level anticyclonic wind flow spans the Caribbean Sea.

SURFACE OBSERVATIONS...HAITI, in Port-au-Prince: VFR. in the
DOMINICAN REPUBLIC: Santiago: MVFR. mist. ceiling 1400 feet.
VFR, elsewhere at all the observation stations.

The GFS MODEL forecast for 250 mb shows that a ridge will start
along the line from N Colombia to SE Cuba, and then to a line
from N Colombia across Hispaniola. Expect W-to-NW wind flow
during the next 48 hours. The GFS MODEL forecast for 500 mb shows
that E-to-SE wind flow will move across the area during the next 2
days, with an Atlantic Ocean ridge. The GFS MODEL forecast for
700 mb shows that broad E-to-SE wind flow, with an intermittent
inverted troughs during day one, and broad anticyclonic wind flow
at the end of day two.

THE ATLANTIC OCEAN...

A deep layer trough is in the east-central sections of the
Atlantic Ocean, along 32N37W 26N35W 20N32W. A trough/shear line
continues from 20N32W to 17N40W 14N50W 15N60W. The trough
supports a cold front that curves through 32N31W to 25N33W to
19N40W. A stationary front continues from 19N40W to 17N47W, and to
16N54W. A surface trough continues from 16N54W to 15N59W to
16N65W in the Caribbean Sea. A large area of comparatively drier
air in subsidence is to NW of the trough/shear line.
Precipitation: scattered moderate to widely strong from 22N
northward between 29W and 32W. isolated moderate rainshowers are
within 90 nm to 150 nm on either side of 20N37W 16N42W 14N50W
13N60W.

Surface anticyclonic wind flow covers the Atlantic Ocean from 17N
northward between 44W and 74W. A 1024 mb high pressure center is
near 29N58W.

A surface ridge passes through the Madeira Archipelago, to 27N21W
to 21N25W, and 11N32W.

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

$$
MT
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