Tropical Weather Discussion
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AXNT20 KNHC 301747

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
147 PM EDT Sun Apr 30 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
1730 UTC.


A cold front extends over the western Gulf of Mexico from 29N93W
to 22N98W. Strong to near-gale northerly winds are already noticed
in observations. Gale-force winds expected to continue through
tonight, when the pressure gradient is expected to relax as the
front moves quickly east. Please refer to the latest National
Hurricane Center High Seas Forecast under AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC, for more details.


The Monsoon Trough remains over Africa. A surface trough extends
from 08N19W to 00N20W. The ITCZ extends west of this trough from
03N21W to 01N38W to 02N50W. Scattered moderate convection is
observed along and near the surface trough between 14W-20W.
Another area of scattered moderate convection prevails within 150
nm on either side of the ITCZ between 30W-50W.



A surface ridge extends across the northeastern portion of the
basin from a high pressure currently centered over the western
and central Atlantic. A cold front extends across the western half
of the Gulf with gale winds behind it. Please refer to the Special
Features section above for details. A squall line extends west of
the front from 29N92W to 27N93W. A 1004 mb surface low is
centered near 20N97W with surface trough extending from the low to
23N96W. Scatterometer data depicts moderate to fresh southerly
winds across the basin east of the front, with some isolated
areas of strong winds possible. Over the next 24-48 hours, the
front stall across the central Gulf while weakening. Surface ridge
will dominate the area.


The pressure gradient across the basin is supporting moderate to
fresh trades. An upper-level trough extends over the west Atlantic
with its base just north of Hispaniola. The diffluent flow
generated by it is supporting abundant cloudiness and persistent scattered
to numerous showers that cover the northeast Caribbean mainly
north of 16N and east of 71W. Dry air and subsidence are limiting
convection across the remainder of the area. A cluster of
moderate to strong convection prevails over the EPAC near the Gulf
of Panama affecting portions of Central America and its adjacent
waters mainly south of 10N. Over the next 24 hours, the showers
and thunderstorms will increase over the southwestern Caribbean in
response to low-level convergence across the area. Otherwise,
little change is expected. The shower activity over the northeast
Caribbean will diminish as the diffluence aloft shifts east.


A diffluent flow aloft prevails across the island supporting
cloudiness and scattered showers mainly over the eastern part.
Similar activity will continue through the evening hours.
Similar scenario is expected during the next 24 hours.


A surface ridge prevails across the basin anchored by a 1028 mb
high centered near 31N67W and a 1026 mb high near 32N32W. An
upper-level trough with axis extending from east to west from
31N51W to 25N58W to 21N71W is enhancing convection over the
northeast Caribbean and south of 22N between 63W-70W. A surface
trough extends from 26N48W to 18N52W. To the east, a weak 1018 mb
surface low is centered near 21N25W. Expect for this low and
fronts to dissipate within the next 24 hours. Little change is
expected elsewhere.

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