Tropical Weather Discussion
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AXNT20 KNHC 211746

205 PM EDT SAT MAY 21 2016

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

Based on 1200 UTC surface analysis and satellite imagery through
1715 UTC.

Tropical wave extends from 02N39W to 08N36W moving W at 15 kt.
The wave coincides with a mid-level 700 mb trough and
associatedrelative vorticity aloft in the vicinity of the
waveaxis near 06N. No significant deep convection is noted
withthe wave.

Tropical wave extends from 03N52W to 09N50W moving W at 10 kt.
This wave coincides with a weaker 700 mb trough
acrossFrenchGuiana and the adjacent coastal waters. No
significant deep convection is noted with the wave at this time.

-The Monsoon Trough extends from the African coast near
07N11Wto05N25W. The Intertropical Convergence Zone axis
extendsfrom 05N25W to 05N38W to 02N51W. Scattered moderate
convection is from 02N to 09N between the Prime Meridian and


Broad middle to upper level troughing is noted on water vapor
imagery over the SE CONUS with global models indicating a thin
ribbon of 500 mb relative vorticity extending from the northern
Florida peninsula to the southwestern Louisiana coast. This
troughing and mid-level energy is supporting a surface trough
analyzed from the Florida panhandle near 30N87W to 28N90W and a
warm front analyzed from the south-central Louisiana coast near
30N92W to the Texas coast near 29N96W. Isolated showers and
tstms are occurring mainly with the warm front in the vicinity
of 28N94W. Otherwise...the remainder of the Gulf is under the
influence of gentle to moderate anticyclonic flow as weak
ridging is expected across the eastern Gulf through Sunday while
a weak frontal boundary..currently stationary...begins to
moveeastward as a cold front tonight into Sunday.

The surface pressure gradient across the Caribbean Sea
remainsrelatively strong due to a nearly stationary ridge
anchored across the central Atlc and lower pressure noted
acrossnorthern South America. The gradient is resulting in
mostly fresh to strong trades across the basin with winds
strongto near gale force within close proximity to the coast
ofColombia. As the high shifts east through Sunday across the
Atlc...the gradient is expected to relax with the area of fresh
to strong trades shifting east as well to primarily S of 15N
between 64W and 74W. upper level trough is
notedon water vapor imagery across the eastern Caribbean with
axis along 63W. East of the axis in the region of maximum
lifting dynamics...scattered showers and tstms are occurring
across the Windward Islands S of 15N between 58W and 62W.

Conditions remain fairly tranquil across the island
withmostlyclear skies noted on satellite imagery this
afternoon.Dry northwesterly flow aloft is further
supportingadryand subsident environment forecast through Sunday.

A middle to upper level low is centered over the Ohio
Rivervalley this afternoon supporting a surface trough
extendingfrom the North Carolina coast to 32N77W to
28N81W.Scattered showers and isolated tstms are
occurringNof28NWof 74W. Farther east...a deep layered
lowiscentered over the central North Atlc and supports
acoldfront analyzed from 32N54W to 29N64W where is
becomesstationary to 29N71W. Widely scattered showers
andisolated tstms are occurring within 90 nm either
sideofthefront. Otherwise...the remainder of the
centralandeastern Atlc is under the influence of a
surfaceridgeanchored by a 1025 mb high centered near 30N35W.

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