[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271202
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Thu May 27 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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1145 UTC.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis along 19W south
of 12N. It is moving westward at 15 kt. Enhanced scattered
moderate to isolated strong convection is within 180 nm east of
the wave from 02N to 03N and also within 120 nm west west of the
wave from 01N to 05N. Scattered showers and isolated thunderstorms
are elsewhere east of the wave axis from 01N to 08N and east to
near 11W. Other scattered showers and isolated thunderstorms are
east of the wave from 01N to 05N, east to 07W.

Another tropical wave has its axis along 35W from 01N to 10N. It
is moving westward near 20 kt. This wave is located under a more
stable upper environment that is marked by subsidence and dry
sinking air found behind an upper-level trough. Scattered
moderate convection within 180 nm east of this wave is confined to
the ITCZ from 03N to 05N. Scattered showers and isolated
thunderstorms are within 120 nm west of the wave from 03N to 05N.

...MONSOON TROUGH/ITCZ...

The monsoon trough remains inland in Africa. The ITCZ is
identified from just west of the tropical wave that is 19W, to
04N27W and to just east of the tropical wave that is along 35W. It
continues from 05N38W to 05N46W and to the coast of French Guiana
near 52W. Increasing scattered moderate to isolated strong
convection is within 60 nm either side of the ITCZ between
41W-46W, and within 60 nm north of the ITCZ  between 46W- 54W.
Similar activity is south of the ITCZ within 30 nm of line from
02N46W to inland the coast of Brazil near 01N52W.

GULF OF MEXICO...

An upper-level trough stretches from the eastern U.S. southwestward
to NE Gulf and continues to near 22N91W. Comparatively drier air
due to subsidence aloft is apparent in water vapor satellite
imagery northwest of the trough to within 120 nm offshore NE
Texas. A sub-tropical jet stream branch cuts across the
southernmost section of the upper-level trough. Associated strong
southwest winds are advecting scattered to broken high clouds from
the eastern Pacific northeastward to across the far southern
Gulf.

A surface ridge axis extends from a western Atlantic 1023 mb
high pressure center near 30N77W westward across north-central
Florida, to near 27N90W and southwestward from there to the far
SW Gulf. A surface trough is just inland the Yucatan Peninsula
northwestward from there to inland central Mexico. Scattered
showers and a few thunderstorms are along the coast Mexico between
94W-97W.

Overnight ASCAT data revealed moderate to fresh northeast to east
winds are within 90 nm of the Yucatan Peninsula coast between
88W-92W. Wave heights are 5 ft or less from 20N to 22N between
91W-93W, also in the central Gulf and in the eastern Bay of
Campeche. Wave heights are 2-4 ft elsewhere.

As for the forecast: Gentle to moderate east to southeast winds
are expected through Sat night as weak high pressure off the NE
Florida coast extends westward to SE Texas and gradually weakens.
Fresh northeast to east winds will pulse nightly to strong off the
Yucatan Peninsula through Sat. A cold front is expected to move
across the northern Gulf on Sat night into Sun, then stall across
the northern Gulf Sun night. Expect moderate north to northeast
winds behind the front.

CARIBBEAN SEA...

An upper-level low is near noted over the Atlantic near 28N65W,
with an associated trough extending from it southwestward to the
northeastern Caribbean. No significant deep convection is seen
in satellite imagery.

The monsoon trough is analyzed from Colombia near 11N74W westward
to central Panama and to the border of Costa Rica and Panama near
09N83W, and well into the eastern Pacific Ocean. Scattered showers
and thunderstorms are along and near the trough, mainly over Costa
Rica and Panama. Debris high level cloudiness from this activity
is streaming eastward over the southwestern Caribbean. Isolated
showers and thunderstorms moving westward are over this same part
of the Caribbean. Isolated showers moving westward with the trade
wind flow are over the northeastern Caribbean.

Overnight ASCAT data showed fresh to strong northeast to east
winds over the central part of the Caribbean south of about 16N
and between 71W-78W. Wave heights with these winds are in the 8-10
ft range. Wave heights elsewhere are in the 3-6 ft range, except
for higher heights of up to 7 ft in the central Caribbean and up
to 6 ft in the Windward Passage.

As for the forecast: Fresh to strong trades will prevail across
the central portions of the Caribbean through early today as high
pressure resides offshore of the NE Florida coast. Winds will
diminish significantly through early next week as the high
collapses. Fresh winds are expected in the southern Gulf of
Honduras and the Windward Passage tonight.

ATLANTIC OCEAN

An upper-level low is vividly noted near 28N65W, with a trough
stretching from it to the northeastern Caribbean Sea. Comparatively
drier air in subsidence is apparent in water vapor imagery from
15N to 25N between 64W-80W. One surface trough is analyzed along a
position from 31N64W to 27N67W. A second trough is analyzed along
65W from just northeast of Puerto Rico north to near 28N65W. Yet
a third trough extends from near 31N52W to 23N55W. A very moist
and unstable atmospheric environment around the upper-level low
along with upper diffluence is supporting increasing numerous
showers and thunderstorms from 24N to 30N between 59W- 64W.
Lightning data indicates frequent strikes with this activity.

A ridge axis extends from a 1024 mb high pressure center that is
near 33N68W, to a 1023 mb high pressure near 30N78W and to across
north-central Florida and to the north-central Gulf of Mexico.

Overnight ASCAT data indicated fresh to strong northeast winds
over the tropical Atlantic waters from 06N to 12N between 45W-53W.
Wave heights in the range of 8-10 ft are roughly within about 500
nm to the north of the ITCZ between 40W-57W.

As for the forecast: Light winds will prevail north of 24N through
today as weak low pressure just east of Bermuda interrupts the
Atlantic ridge. Moderate to locally fresh winds will continue
across the Bahamas and Greater Antilles through early today. Winds
will become gentle to moderate today through Sun as the Atlantic
ridge extends from the east-central Atlantic weakly WSW to
Florida. Fri night, moderate to fresh southerly winds will develop
off the NE Florida coast ahead of a cold front forecast to emerge
off the southeastern CONUS early Sun. The cold front will move
across northern Florida on Sun before stalling Sun night.


$$
Aguirre
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