Tropical Weather Discussion
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000
AXNT20 KNHC 181759
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
159 PM EDT Sat Mar 18 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.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough passes through the coastal sections of Liberia
near 06N11W, to 04N12W and 01N17W. The ITCZ continues from 01N17W,
crossing the Equator along 20W, to 01S24W 01S30W, and 02S40W.
Convective precipitation: widely scattered moderate to isolated
strong to the south of 07N12W 04N30W 02N36W, and from 06N
southward between 47W and 52W. Rainshowers are possible elsewhere
from 11N southward from 60W eastward.

...DISCUSSION...

...THE GULF OF MEXICO...

The base of a middle level-to-upper level trough is moving through
the eastern part of the Gulf of Mexico, moving into the Straits of
Florida now. Upper level anticyclonic wind flow, from a ridge,
covers the Gulf of Mexico from 27N southward from 88W westward.

Surface anticyclonic wind flow spans the entire area. A surface
ridge extends from a 1028 mb NE Florida high pressure center that
is near 29N82W, toward the NW corner of the Gulf of Mexico, and
into the SW corner of the area.

...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: none.

IFR: none.

MVFR: KBBF.

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

TEXAS: MVFR from Hebbronville, into the comparatively more
interior sections of the Lower Rio Grande Valley. MVFR from
Victoria/Port Lavaca/Palacios to the middle Texas Gulf coast.
MVFR from the Houston metropolitan area and surrounding smaller
communities to Conroe. IFR in Jasper. LOUISIANA: LIFR in parts of
the Lake Charles metropolitan. MVFR along the NW coast of Lake
Pontchartrain. MISSISSIPPI: MVFR in Natchez and McComb. ALABAMA
and FLORIDA: VFR.

...FROM THE ATLANTIC OCEAN THAT IS FROM 50W WESTWARD...ACROSS THE
BAHAMAS AND CUBA...INTO THE NW CORNER AND THE WESTERN SECTIONS OF
THE CARIBBEAN SEA...

Upper level SW wind flow moves from the NW corner of the Caribbean
Sea, across Cuba and the Bahamas, into the central Atlantic
Ocean. Middle level-to-upper level W-to-SW wind flow covers the
Atlantic Ocean that is to the west of the stream of SW wind flow.
A cold front passes through 32N48W to 30N51W 29N55W and 27N59W.
The front becomes stationary from 27N59W to 21N70W, across the NW
corner of Haiti, to the eastern part of Jamaica, to the E coastal
sections of Honduras. Convective precipitation: broken to overcast
multilayered clouds and possible rainshowers are to the NW of the
line that passes through 32N43W 25N57W 16N75W 09N80W, from the
Atlantic Ocean into the Caribbean Sea.

...THE REST OF THE CARIBBEAN SEA...

Upper level SW wind flow moves across Central America, from
Nicaragua to Guatemala and Belize, across and beyond Jamaica,
Cuba, Hispaniola, and the Bahamas, into the Atlantic Ocean.
Upper level anticyclonic wind flow spans the Caribbean Sea that is
to the east of the upper level SW wind flow.

Broad cyclonic wind flow and comparatively drier air in subsidence
cover the area that is to the east of the upper level SW wind
flow, from 350 mb to 500 mb, and from 600 mb to 800 mb.

Broken low level clouds and rainshowers cover the area that is
from 11N to 18N between 60W and 70W. The clouds and precipitation
are associated with a now-dissipated surface trough that moved
across the islands of the eastern Caribbean Sea during the last
24 hours.

24-hour rainfall amounts, for the period ending at 18/1200 UTC,
according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION
TABLES, MIATPTPAN/SXCA01 KNHC, are: 0.37 in Kingston in Jamaica,
0.17 in Guadeloupe, 0.07 in Nassau in the Bahamas, and 0.02 in
San Juan in Puerto Rico.

...HISPANIOLA...

Middle level to upper level SW-to-W wind flow is moving across
the island.

SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: VFR. for the
DOMINICAN REPUBLIC: Barahona: VFR. Santo Domingo: VFR. La Romana:
MVFR. ceiling 2000 feet. Punta Cana: nearby rainshowers. MVFR.
ceiling 1800 feet. Santiago: MVFR. ceiling 1800 feet. Puerto
Plata: VFR.

The GFS MODEL forecast for 250 MB shows that SW wind flow will
move across the area. The GFS MODEL forecast for 500 MB shows
that W wind flow will move across the area. Hispaniola will be at
the southern end of an Atlantic Ocean-to-Hispaniola trough.
The GFS MODEL forecast for 700 mb shows that cyclonic wind flow
with an inverted trough will cover most of the island during the
first 24 hours of the 48-hour forecast period. The easternmost
part of the island will experience anticyclonic wind flow during
that same period. Expect anticyclonic wind flow during day two.

...THE REST OF THE ATLANTIC OCEAN...

An upper level trough extends from a cyclonic circulation center
that is near 31N15W to a 29N19W cyclonic circulation center, to a
third cyclonic circulation center that is near 17N35W. Upper level
cyclonic wind flow covers the Atlantic Ocean to the east of the
line that runs from 30N36W to 19N49W to 10N50W. A 1014 mb low
pressure center is near 30N16W. A surface trough extends from the
low pressure center to 33N17W in the Madeira Archipelago. A
surface trough is along 37W/38W from 15N to 22N. Convective
precipitation: rainshowers are possible in the areas of cyclonic
wind flow.

Surface anticyclonic wind flow is to the east and to the west of
the Atlantic Ocean-to-Caribbean Sea cold front/stationary front.
A surface ridge passes through 32N38W to 25N45W and 19N65W.
Surface anticyclonic wind flow also is to the W and NW of the
cold front. A ridge passes through 32N60W to a 1028 mb high
pressure center that is near 31N69W, beyond a NE Florida 1028 mb
high pressure.

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

$$
MT



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