Tropical Weather Discussion
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000
AXNT20 KNHC 201803
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
103 PM EST Fri Jan 20 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...SPECIAL FEATURES...

An Atlantic Ocean cold front passes through 31N51W to 26N55W and
23N65W. The current conditions consist of: SW gale-force winds,
and sea heights ranging from 12 feet to 15 feet, to the north of
28N to the east of the front to 48.5W. W Gale-force winds, and
sea heights ranging from 13 feet to 15 feet, are to the north of
30N to the W of the front to 55W. These conditions are expected to
continue for the next 12 hours or so. Please read the latest NWS
High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC
for more details.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough passes through Liberia near 07N11W to 05N13W.
The ITCZ continues from 05N13W to 03N16W 03N19W 02N22W 02N34W and
01N38W. Convective precipitation: Widely scattered moderate to
isolated strong from 06N10W 06N22W 08N30W 03N34W, to the equator
along 35W. Convective precipitation is weakening and dissipating
from 06N between 40W and 50W.

...DISCUSSION...

...THE GULF OF MEXICO...

Middle level-to-upper level anticyclonic wind flow spans the Gulf
of Mexico. A ridge is along 88W.

A surface trough cuts through W Texas, into northern Mexico, to NE
coastal Mexico, into the SW corner of the Gulf of Mexico, into
southern Guatemala. SE surface wind flow is prevalent.

Rainshowers and thunderstorms will accompany a strong cold front,
that is forecast to move into the northwestern part of the Gulf of
Mexico on Saturday night. The front will reach from SE Louisiana
to Tampico Mexico by Sunday morning, and from the Florida Big
Bend to the Yucatan Peninsula by Sunday evening. Strong to gale
force winds are possible behind the front from Sunday through
Monday across the northern and central Gulf, possibly spilling
into the southeastern Gulf of Mexico, with seas building as high
as 16 to 19 ft. Conditions will improve gradually from west to
east Monday night through Tuesday night as high pressure builds in
behind the front.

...LOW LEVEL CLOUD CEILINGS AND WEATHER FOR THE OFFSHORE OIL
PLATFORM SITES THAT ARE IN THE AREA WHOSE BOUNDARIES ARE FROM 27N
NORTHWARD AND FROM 88W WESTWARD...

LIFR: KVBS.

IFR: KEIR, and KSPR.

MVFR: KBBF, KHHV, KVAF, KEMK, KGUL, KHQI, KVQT, KATP,
KIKT, KVKY, KMIS, and KDLP.

LOW LEVEL CLOUD CEILINGS AND WEATHER...FOR THE COASTAL PLAINS OF
THE U.S.A. FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...

TEXAS: LIFR/IFR in the Lower Valley, with light rain in McAllen.
LIFR and light rain from Hebbronville into the middle Texas Gulf
coastal areas, to Bay City. IFR in Conroe. MVFR in Huntsville.
LOUISIANA: MVFR in the southernmost sections of the state. IFR in
the SE corner. IFR in Baton Rouge. MVFR around the northern side
of Lake Pontchartrain, and at the NAS New Orleans. MISSISSIPPI:
IFR in Biloxi and Pascagoula. MVFR at the Stennis Airport and in
parts of the Hattiesburg. ALABAMA: IFR in Gulf Shores. MVFR in
Mobile and at Fort Rucker. FLORIDA: MVFR in the Pensacola
metropolitan area. light rain at the NAS Pensacola. MVFR and rain
from Mary Esther to Valparaiso, MVFR in Destin. MVFR in the NW
part of the Panama City metropolitan area, in Tallahassee, and
Cross City.

...THE CARIBBEAN SEA...

Upper level NW wind flow is moving across The Greater Antilles,
downstream from the Gulf of Mexico anticyclonic wind flow and
ridge.

Upper level NW wind flow reaches the Windward Passage, and it
curves cyclonically through the Caribbean Sea from 80W eastward,
toward South America. Upper level anticyclonic wind flow covers
the area that is from 80W westward. Comparatively drier air in
subsidence, that is apparent in water vapor imagery, spans the
Caribbean Sea.

Trade wind flow will diminish in the south central Caribbean Sea
through early next week as the high pressure weakens and shifts
eastward ahead of an approaching cold front. The front is
forecast to reach the Yucatan Channel and the northwestern part of
the Caribbean Sea on Sunday night. The front will be accompanied
by strong winds and building seas. The front will reach from the
Windward Passage to the eastern coast of Nicaragua on Monday
night, with strong southwest winds expected near the Windward
Passage just ahead of the front. Expect continued mainly gentle
to moderate trade winds and seas of 4 feet to 6 feet in the
tropical north Atlantic Ocean.

No significant 24-HOUR rainfall amounts have been reported, for
the period ending at 20/1200 UTC...according to the PAN AMERICAN
TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...
a trace in Guadeloupe.

...HISPANIOLA...

Upper level NW wind flow is moving across Hispaniola.
Comparatively drier air in subsidence is apparent in water vapor
imagery, across the entire area.

SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: VFR. for the
DOMINICAN REPUBLIC: Barahona: VFR. Santo Domingo/La Romana/Punta
Cana: VFR. Santiago/Puerto Plata: VFR.

The GFS MODEL forecast for 250 MB shows that NW wind flow will
move across the area during the next 48 hours, with a N Colombia-
to-southern Mexico ridge. The GFS MODEL forecast for 500 MB shows
that northerly wind flow will move across the area during the next
48 hours, with a trough to the east and an anticyclonic
circulation center to the west. The GFS MODEL forecast for 700 mb
shows that northerly wind flow will move across Hispaniola during
the next 48 hours.

...THE ATLANTIC OCEAN...

A deep layer central Atlantic Ocean trough is supporting a cold
front that passes through 31N51W to 26N55W and 23N65W.
Convective precipitation: scattered to numerous strong within 45
nm on either side of 26N51W 29N49W 32N47W. Isolated moderate
elsewhere from 20N northward between 40W and 50W. Rainshowers are
possible in the Atlantic Ocean from 18N to 25N between 56W and
70W.

An upper level trough passes through 32N13W, across the Canary
Islands, to 25N20W. A surface trough is along 31N22W 29N25W
30N28W. Rainshowers are possible from 28N northward between Africa
and 30W.

A surface ridge, that is to the east of the central Atlantic Ocean
cold front, is along 18N44W 25N36W 28N31W.

A 1017 mb high pressure center is near 23N76W in the Bahamas.
Surface anticyclonic wind flow covers the areas that are from 17N
to 29N between 70W and 83W.

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

$$
MT



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