Tropical Weather Discussion
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000
AXNT20 KNHC 211034
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
533 AM EST Tue Nov 21 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
0945 UTC.

...SPECIAL FEATURES...
Cyclogenesis is expected to occur late Wednesday into Wednesday
night across portions of the Gulf of Mexico producing near gale to
gale force northerly winds S of 22N W of 93W. The gale force wind
field is expected to persist through late Wednesday night...
diminishing into strong to near gale force strength by Thursday
morning across portions of the SW Gulf of Mexico. See the latest
NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02
KNHC for more details.

...ITCZ/MONSOON TROUGH...
The monsoon trough extends from the African coast near 11N16W to
09N19W. The Intertropical Convergence Zone axis extends from
09N19W to 08N33W to 06N42W to 05N52W. Scattered moderate
convection is from 02N-11N between 08W-37W.

...DISCUSSION...

GULF OF MEXICO...
A middle to upper level trough is noted on water vapor imagery
over the western Gulf with axis extending from 31N91W to a base
over the SW Gulf waters near 21N94W. The trough supports a surface
trough extending from 28N86W to 24N87W to 22N93W to 20N95W.
Scattered showers and isolated tstms are occurring within 90 nm
either side of the boundary. Otherwise...generally gentle to
moderate E-SE winds prevail across the basin this morning on the
southwestern periphery of a surface ridge anchored by a 1027 mb
high centered offshore of the Carolinas near 36N73W. The
troughing moving over the basin will strengthen the current
surface troughing across the eastern waters and a frontal wave
across the western waters through early Wednesday with fresh to
strong northerly winds expected to materialize by Wednesday
afternoon into the evening. Global models indicate cyclogenesis
across central and eastern portions of the basin Wednesday night.

CARIBBEAN SEA...
Southwesterly flow aloft prevails over the western Caribbean with
a ribbon of mid-level energy stretching from over the Windward
Passage region W-SW to over portions of Central America in the
vicinity of Honduras and El Salvador. This mid-level energy is
supporting a surface trough analyzed from 12N78W to 19N75W.
Widely scattered showers and isolated tstms are occurring N of 15N
between 70W-80W. A portion of this activity extends N of the
Windward Passage region in the Atlc waters. Otherwise...moderate
trades are noted E of 77W and moderate to occasional fresh NE
winds are occurring W of 77W. This pattern is forecast to persist
through Thursday night.

...HISPANIOLA...
A surface trough lies to the SW of the island with widely
scattered showers and isolated tstms occurring generally W of
the island this morning across the Windward Passage region. The
surface troughing will be slow to move and dissipate through
Wednesday...so little change is expected through mid-week.

ATLANTIC OCEAN...
A cold front extends into the discussion area near 32N55W and
continues SW to 29N61W becoming stationary to the NW Bahamas and
offshore waters of southern Florida. Isolated showers are
occurring within 60 nm either side of the front. To the N of the
front...surface ridging prevails anchored by a 1027 mb high
centered offshore of the Carolinas near 36N73W. SE of the
front...mid-level shortwave troughing is in the vicinity of
24N66W and supports a surface trough analyzed from 22N68W to
28N62W. Scattered showers and isolated tstms are occurring from
20N-28N between 57W-70W...and from 20N-23N between 70W-77W.
Farther east...another middle to upper level trough is noted in
the vicinity of 25N39W supporting a 1012 mb low centered near
24N38W with the associated stationary front extending SW from the
low to 19N50W to 22N61W. Scattered showers and isolated tstms are
occurring within 75 nm either side of the front. This low links
up with a 1007 mb low centered near 32N27W by way of a cold front
extending from 32N27W to 24N34W then stationary into the 1012 mb
low. Scattered showers and isolated tstms are occurring generally
N of 25N between 16W-37W.

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

$$
HUFFMAN




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