AXNT20 KNHC 202323

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Apr 21 2021

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
2300 UTC.


The monsoon trough passes through the coastal sections of Sierra 
Leone near 08N13W and continues SW to near 03N24W. The ITCZ 
continues from 03N24W to 01N40W to the coast of Brazil near 
02N51W. Scattered moderate convection is from 00N-03N between 
26W-31W. Similar convection is within about 45 nm S of the 
monsoon trough between 17W-19W.


A stationary front extends from near Sarasota, Florida to 24N90W
to a 1014 mb low pressure at 21N95W. The low is well defined on
satellite imagery, and an area of showers and thunderstorms is
just S of the front over the SE Gulf. The stationary front will 
transition back to a cold front reaching the far southeastern 
Gulf Wed night. The low is forecast to lose its identity along 
the front by early Wed. Scattered showers and thunderstorms will 
be focused along and near the front tonight into Wed morning. 
Some of this activity may produce strong gusty winds and rough 
seas. Another cold front is forecast to reach the coast of Texas 
this evening and gradually weaken on Wed. Reinforcing cold air 
behind the front will support the movement of the aforementioned 
stationary front.

High pressure in the wake of the primary front will shift eastward
through Sat night as a cold front reaches eastern Texas. Fresh 
to strong southerly return flow will develop over the NW Gulf Fri,
shift to the central Gulf early Sat and diminish by late Sat as 
the cold front moves across the NW Gulf and central Gulf waters. 
This front will become stationary across the central Gulf Sun 
and Sun night as a weak gradient sets up over the area.


The most recent scatterometer data provided observations of fresh
to strong winds across the south-central Caribbean, including the
Gulf of Venezuela. Seas are in the 7-10 ft range. This area is 
cloud free. Elsewhere, mainly moderate E-SE winds are noted with
seas of 4-7 ft across the eastern Caribbean, and 4-6 ft over the
NW Caribbean. Visible satellite imagery shows narrow lines of 
clouds forming parallel to the E-SE winds. Currently, convection
is flaring up over the NE Yucatan peninsula. Scattered showers 
and thunderstorms are also noted over parts of Central America. 

Fresh to strong trade winds over the central Caribbean will diminish
by late in the week as high pressure over the central Atlantic shifts
eastward, except near the coast of Colombia where these winds will
persist through the week. 


As of 1800 UTC and W of 65W, a weak cold front extends from near
Bermuda to 27N76W, where it transitions to a stationary front to
Melbourne, Florida. The cold front will become stationary near 
30N tonight, while the stationary portion of the front will begin
to slowly move southward as a cold front. By late Wed, the 
stationary front will have lifted back to the N as a warm front, 
while the cold front will have reached from near 31N69W to the 
central Bahamas and to west-central Cuba as yet another cold 
front moves over the NW waters. By late Thu, both fronts will be 
weakening NE of the Bahamas as high pressure builds in over the 
area. The high pressure will shift eastward through Sat night as 
a stronger cold front approaches the southeastern U.S. coast. 
This front is expected to move across the NW and north-central 
waters Sun and Sun night preceded by fresh to strong southerly 
winds and possible scattered showers and thunderstorms.

E of 65W, high pressure of 1024 mb located near 27N38W dominates
the remainder of the Atlantic forecast waters. Moderate to fresh
trades are noted per scatterometer data from 10N-20N between the
coast of west Africa and the Lesser Antilles. The high pressure 
will weaken by late Wed, and will be replaced by another high
pressure system located over the central Atlantic by Wed night.