Tropical Weather Discussion
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AXNT20 KNHC 261716

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
116 PM EDT Thu Apr 26 2018

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.


The monsoon trough enters the Atlantic Ocean through Liberia and
continues to 04N22W. The ITCZ extends from 04N22W to 03N30W to
01N40W to the Equator at 50W. A cluster of moderate to strong
convection is noted over parts of Sierra Leone and Liberia, and
the adjacent Atlantic waters from 05N-07N E of 13W. Similar
convection is also seen elsewhere from 03N-06N between 10W-15W.
Scattered moderate convection is within about 90 nm S of ITCZ axis
between 22W-25W, and near the Equator at 32W.



As of 1500 UTC, a cold front extends from SE Louisiana to the
coast of Tamaulipas, Mexico near 25N97W. An area of showers with
embedded tstms is ahead of the front over the SW gulf, including
the Bay of Campeche, associated with a short-wave trough moving
across that area. The front will reach the SE Gulf Sat where it
will stall and dissipate. High pressure will build in the wake of
the front and prevail through Mon. Under the influence of this
system, a gentle to moderate anticyclonic flow will prevail across
the gulf waters, with seas generally under 5 or 6 ft. A nearly
stationary front is over the far SE gulf and the Straits of
Florida producing scattered showers and tstms. It is forecast to
become diffuse late today. A weak 1015 mb high pressure is
centered over the SE Gulf near 25N84W. This system will move
across South Florida into the Bahamas through tonight keeping dry
weather conditions over South Florida. A thermal trough will
develop during the evening hours over the Yucatan peninsula before
pushing offshore into the SW gulf each night. A surge of moderate
to fresh NE-E winds will accompany this trough, with seas
building to around 5 ft.


As previously mentioned, a nearly stationary front is over the
far SE Gulf of Mexico and the Straits of Florida. Scattered
showers and tstms are along the frontal boundary. Part of this
convective activity is reaching western Cuba and the Yucatan
Channel. The front is forecast to become diffuse late today. A
surface trough is moving across Puerto Rico generating scattered
showers and isolated thunderstorms over parts of the UK/US Virgin
Islands and adjacent waters, and across eastern Puerto Rico.
Additional showers and thunderstorms are expected to develop
across the island during the afternoon hours. Moisture associated
with this trough will reach Hispaniola late today. The most recent
scatterometer data show moderate SE winds behind the trough axis
as well as fresh trades across the ABC Islands and the Gulf of
Venezuela. Fresh to locally strong trade winds will prevail over
the south-central Caribbean through Sat night. Moderate trades
are expected elsewhere through Mon.


As of 1500 UTC, a nearly stationary front extends from 31N71W
southwest across the central Bahamas and the Straits of Florida.
An area of showers and tstms is over the central Bahamas and
regional waters in association with this frontal boundary. This
front will dissipate late today. A second cold front will move
into the northwest waters Fri night, reach from 31N74W to southern
Florida Sat night, then slowly dissipate by Sun morning. A third
cold front will push south of 31N Sun, and reach from 30N65W to
the northern Bahamas Mon night.

Another cold front enters the forecast area near 31N45W and
continues SW to 23N50W to 24N58W. Scattered showers and tstms are
along the front N of 25N. The front is associated with a weak
1016 mb low pressure that moved into the forecast waters since
yesterday. A well defined swirl of low clouds is associated with
the low center, forecast to dissipate in about 24 hours. A recent
ASCAT pass indicates fresh winds on the NW quadrant of the low
center. The remainder of the Atantic Ocean is under the influence
of a 1030 mb high pressure located SW of the Azores near 35N30W.
The pressure gradient between this high and lower pressure over
Africa is resulting in moderate to fresh northerly winds between
the coast of Africa and 20W and N of 15N.

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