Atlantic Tropical Weather Discussion (Text)

AXNT20 KNHC 210526

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1226 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 0000 UTC surface analysis and satellite imagery through 
0445 UTC.

The monsoon trough extends from the African coast near 11N15W to 
08N27W. The Intertropical Convergence Zone axis extends from 
08N27W to 08N35W to 09N42W to 08N52W to 12N62W. Scattered 
moderate convection is from 02N-10N between 09W-37W. 


A middle to upper level trough is noted on water vapor imagery
over the western Gulf with axis extending from 31N93W to a base
over the SW Gulf waters near 21N96W. The trough supports a
weakening and dissipating stationary front extending from the
Florida Straits near 25N80W to 22N90W to 20N96W. Widely scattered
showers and isolated tstms are occurring within 90 nm either side
of the front...and across much of the central Gulf waters between
86W-92W. Otherwise...generally gentle to moderate easterly winds
prevail across the basin this evening on the southwestern 
periphery of a surface ridge anchored by a 1025 mb high centered
across coastal Carolina near 35N76W. The troughing moving over the
basin will induce surface troughing across the eastern waters and
a frontal wave across the western waters early Wednesday with 
fresh to strong northerly winds expected to materialize by 
Wednesday afternoon into the evening hours. Global models indicate
cyclogenesis across central and eastern portions of the basin
Wednesday night into Thursday.

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 pair of surface troughs...one analyzed from 11N78W to
20N73W and the other analyzed from 09N83W to 17N82W. Widely
scattered showers and isolated tstms are occurring N of 16N
between 68W-79W...and S of 17N between 78W-85W. A portion of this
activity extends NE of Hispaniola into the Atlc waters.
Otherwise...moderate trades are noted E of 77W and moderate to
occasional fresh NE winds occurring W of 77W. This pattern is
forecast to persist through Thursday night.

Located between a pair of surface troughs...widely scattered
showers and isolated tstms are occurring across the island this
evening. The surface troughing will be slow to move and dissipate
through Wednesday...so little change is expected through mid-week.

A cold front extends into the discussion area near 32N62W and
continues SW to 28N70W becoming stationary to the NW Bahamas and
Florida Straits. Isolated showers are occurring within 60 nm
either side of the front. To the N of the front...surface ridging
prevails anchored by a 1025 mb high centered across coastal
Carolina near 35N76W. SE of the front...mid-level shortwave
troughing is in the vicinity of 25N66W and supports a surface
trough analyzed from eastern Hispaniola near 19N69W to 25N65W.
Scattered showers and isolated tstms are occurring from 19N-27N
between 56W-73W. Farther east...another middle to upper level
trough is noted in the vicinity of 26N39W supporting a 1008 mb low
centered near 32N29W with the associated cold front extending SW
from the low to 24N40W to 19N51W becoming stationary to 21N58W.
Scattered showers and isolated tstms are occurring N of 25N
between 18W-37W...and within 120 nm either side of the front. To
the N of the front a surface ridge prevails anchored by a 1021 mb
high centered near 31N50W.

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Page last modified: Tuesday, 21-Nov-2017 05:27:04 UTC