Tropical Weather Discussion
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000
AXNT20 KNHC 232343
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
743 PM EDT Mon Oct 23 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 1800 UTC surface analysis and satellite imagery through
2315 UTC.

...SPECIAL FEATURES...
A cold front is currently analyzed across the Gulf waters from the
Florida Big Bend near 30N84W SW to 23N90W WSW to the Mexico coast
near Tampico. A surface trough boundary extends southward from the
front near 21N96W to the Mexico coast near 18N94W. Near gale to
gale force NW winds are occurring S of 21N W of 95W to the west
of the surface trough axis. The gale force winds are expected to
be short lived as the pressure gradient weakens during the
overnight hours. The wind field will once again increase into near
gale to gale force conditions Tuesday afternoon as the cold front
pushes through the SW Gulf waters. Please see the latest NWS High
Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for
more details.

...TROPICAL WAVES...
A tropical wave extends from 06N57W to 17N57W moving W at 10-15
kt. The wave coincides with broad 700 mb troughing between 50W-
60W and a maximum in 850 mb relative vorticity along the wave axis
near 10N. Scattered moderate convection is from 07N-18N between
52W-62W and continues to be enhanced by a middle to upper level
trough with axis extending from 21N63W southward to a broad base
over northeastern South America.

A tropical wave extends from 10N91W to 19N93W moving W at 10-15
kt. The wave coincides with 700 mb troughing between 87W-94W and
a maximum in 850 mb relative vorticity along the wave axis near
17N. Widely scattered moderate convection is from 13N-20N between
88W-96W.

...ITCZ/MONSOON TROUGH...
The monsoon trough extends from the African coast near 14N17W to
10N21W. The Intertropical Convergence Zone axis extends from
10N21W to 07N28W to 06N45W. Scattered moderate convection is from
05N-11N between 22W-48W.

...DISCUSSION...

GULF OF MEXICO...
A vigorous middle to upper level trough is progressing
northeastward over the Tennessee and Ohio River valleys this
evening supporting a cold front extending from the Florida Big
Bend region SW to 23N90W to the Mexico coast near Tampico.
Scattered showers and isolated tstms are occurring within 150 nm
east of the front and across interior portions of northern and
central Florida. In addition...a surface trough extends from the
front near 21N96W to 18N94W inducing the near gale to gale force
NW winds mentioned above in the special features section.
Widely scattered showers and isolated tstms are occurring
generally S of 22N between 88W-97W. Otherwise...a surface ridge
anchored by a 1021 mb high centered across SE Texas near 30N96W is
providing moderate to fresh N to NE winds west of the front. This
ridge will continue to gradually build southeastward through early
Tuesday with a secondary reinforcing cold front...currently across
Oklahoma and portions of western Texas...expected to surge SE
Tuesday and Tuesday night increasing northerly winds across much
of the basin into Wednesday. Strong high pressure in wake of the
front will build in across New Mexico and Texas...and into the
western Gulf Wednesday night into Thursday.

CARIBBEAN SEA...
An upper level anticyclonic circulation is centered over the
western Caribbean near 15N82W and continues to provide an overall
divergent environment aloft promoting scattered to numerous
showers and scattered strong tstms from 11N-20N between 78W-
88W...including inland portions of Central America. At the
surface...this activity focused on maximized moisture convergence
near a surface trough analyzed from 12N82W to 18N86W. Farther
south...the addition of the monsoon trough axis along 11N between
northern Colombia and Costa Rica is also providing focus for
scattered showers and tstms S of 11N between 71W-86W. Finally...a
tropical wave is approaching the Lesser Antilles currently noted
along 58W. Scattered showers and tstms are occurring from 07N-18N
between 52W-62W and this area is expected to continue moving
westward. Enhancing portions of this convection is an upper level
low centered to the N-NW near 22N63W. Otherwise...moderate to
fresh trades prevail across the basin this evening.

...HISPANIOLA...
Dry air aloft within northerly flow will support fair weather
across the island through Tuesday. Moderate to fresh trades are
expected through Wednesday.

ATLANTIC OCEAN...
Much of the SW North Atlc is under the influence of a surface
ridge anchored by 1032 mb high centered near 41N61W. Within the
western periphery of this ridging...upper level divergence is
maximized with scattered showers and isolated tstms occurring N of
27N W of 75W as a cold front approaches the eastern seaboard this
evening into early Tuesday. Otherwise...within the southern
periphery of the ridge...moderate to fresh E-SE winds are
occurring generally W of 62W. Farther east...an upper level low is
centered near 22N63W. The upper level low supports a surface
trough extending from 20N58W to 26N58W with scattered showers and
tstms occurring from 22N-29N between 52W-63W. This area lies SW of
a cold front extending into the discussion area near 32N38W
extending SW to 28N48W then stationary to N of the surface
troughing near 28N57W. Widely scattered showers and isolated tstms
are possible within 120 nm either side of the frontal boundary.
Finally...another middle to upper level shortwave trough is noted
on water vapor imagery in the vicinity of 28N28W. This feature
supports another weak surface trough extending from 23N28W to
29N21W and provides focus for scattered showers and isolated tstms
occurring from 19N-31N between 23W-30W.

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

$$
HUFFMAN




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