[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080000
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM Tue Apr 07 2020

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
2345 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the southern coast of
Sierra Leone near 08N13W to 05N20W, where morning scatterometer
data indicated that the ITCZ axis begins and continues to 03N30W
to 01N40W and to the coast of Brazil near 00S48W. Scattered
moderate to isolated strong convection is within 150 nm south of
the ITCZ axis between 27W-35W. Scattered moderate convection is
within 30 nm of the ITCZ axis between 35W-42W and also north of
the ITCZ axis within 30 nm of a line from 02N39W to 02N45W to
02N51W.

GULF OF MEXICO...

High pressure, both at the surface and aloft, is keeping hold of
the weather pattern across the basin as a rather strong jet-
stream branch rounds the northern periphery of the high pressure
over the southern states. Active weather is riding eastward over
the southern states with this jet-stream branch. The high
pressure at the surface remains weak as a 1019 mb high center is
analyzed over the far NE Gulf just northwest of Tampa, Florida.
The related pressure gradient is allowing for generally light
east to southeast winds throughout, with the exception of
southern part of the central Gulf and the eastern part of the SW
Gulf where gentle to moderate southeast to south winds are
present. Wave heights are in the low range of 2-4 throughout,
except for slighter higher wave height values of 3-5 ft in the
central Gulf area.

A faint line of low clouds note on visible imagery extends from
near Key West, Florida at 24N82W, northwestward to 26N85W and to
near 28N86W as was captured in an Ascat pass. No significant
weather is associated to this trough. Dissipating low clouds are
over the far NW Gulf and over the SW and western Gulf from 19N to
28N between 93W and 96W. Surface observations along the coast of
Mexico are showing reduced visibilities to 5 miles. This is due
to smoke from agricultural fires that are occurring in southern
Mexico. The occurrence of agricultural fires over southern Mexico
and sections of Central America is typical for this time of
year.

The forecast calls for aforementioned high pressure to be the
dominate feature through the next few days. A cold front is
expected to reach the northern Gulf Thu night into Fri. The
front will become stationary and weaken over the northern or
central waters Fri night. Fresh to locally strong northeast to
east winds will follow in behind the front. Southerly winds will
increase across the region during the upcoming weekend. Patchy
fog may form along and just inland the central Texas coast
tonight into Wed morning. There exists the possibility that
smoke from agricultural fires in southern Mexico leading to
reduced visibilities over the SW Gulf and Bay of Campeche.

CARIBBEAN SEA...

Like the Gulf of Mexico basin, generally weak high pressure is
present across the Caribbean Sea as the typical Colombia low
pressure is situated near 10N74W. In addition, dry air associated
with a mid-level ridge over the NW Caribbean and strong winds
aloft over the remainder of the Caribbean continue to inhibit
deep convection from developing. The gradient between the high
pressure and the low is producing gentle to moderate trade winds
across just about the entire Caribbean, except for south of 13N
where fresh northeast to east winds were highlighted by an
Ascat pass.

Satellite imagery shows low-level moisture, in the form of
broken low-level cloud lines, advecting from northeast to
southwest over the far NE and central Caribbean waters. This
moisture is based off an old frontal boundary, now analyzed as
a trough, that extends from northeast of the Leeward Islands
southwestward to the vicinity of the Leeward Islands. Isolated to
scattered showers are occurring with and near this boundary.
This activity is expected to last through Wed. Otherwise, shower
activity remains limited to non-existent across the rest of the
basin.

The forecast calls for building high pressure over the SW North
Atlantic waters will support fresh to strong winds along the
coast of Colombia and in the Gulf of Venezuela through Thu
morning. Fresh winds will pulse each night over the Gulf of
Honduras, possibly attaining strong speeds by this weekend. A
trough will linger in the vicinity of the Leeward Islands through
Wed while lifting northward. Long-period northerly swell will
continue affecting the waters east of the Lesser Antilles through
tonight. Another round of northerly swell will impact these
waters Thu night into this weekend.

ATLANTIC OCEAN...

In the upper-levels broad upper troughing is noted over the
central Atlantic north of about 20N and between 40W-62W, while
the eastern periphery of the Gulf of Mexico high pressure
protrudes eastward to the Bahamas. Broad ridging aloft is to the
south of this trough. At the surface, like in the Gulf of
Mexico, weak high pressure of 1019 mb is analyzed at 28N75W. A
surface trough, remnants of a previous front, extends from near
21N52W to the vicinity of the Leeward Islands. Isolated showers
are possible along and near this trough. Patches of broken to
overcast low and mid-level clouds along scattered showers and
small isolated thunderstorms are quickly moving eastward north
of about 26N and between 47W-58W as a mid to upper-level trough
swings eastward over that part of the area. The tail-end of an
eastern Atlantic cold front extends southwestward from 32N28W to
near 29N32W, where it transitions to a trough southwest to near
23N44W. A mid-level shortwave trough passing across the front and
trough in combination with low-level convergence ahead of the
front and trough is resulting in scattered showers and possible
isolated thunderstorms to exist within 240 nm east of cold front
and within 120 nm east of the trough north of 25N. Scatterometer
data passes from today highlighted gentle to moderate winds
throughout the area, except for light to gentle winds from 16N to
24N between 41W-65W and also from 21N to 29N west of 65W.

Northerly swell continues to propagate through much of the
central Atlantic waters bringing wave heights of 8-12 ft
north of 25N.

The forecast calls for the high pressure centered at 28N75W to
shift southeastward through Wed. It will maintain a ridge across
the southern waters through Fri. A trough will move across he
northern waters Wed night and Thu. Fresh to strong southerly
winds are expected across the northern waters ahead of the
trough. A cold front is expected to move southeastward across the
SW N Atlantic waters Thu night through Sat night. Southerly
winds, of fresh speeds, are forecast to develop east of Florida
late Sat night into Sun between low pressure over the
southeastern United States and a ridge over the western Atlantic.

$$
Aguirre
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