[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250545
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Wed Aug 25 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 0000 UTC surface analysis and satellite imagery through
0530 UTC.

...SPECIAL FEATURE...

Heavy Rainfall in southern Central America: A broad area of low
pressure is expected to form in the SW Caribbean Sea later this
week. This is expected to result in an increase in moisture and
unstable conditions in southern Central America. Heavy rainfall
is expected in SE Nicaragua, Costa Rica, Panama, and NW Colombia
through early in the weekend. The heaviest precipitation is
forecast to affect southern Costa Rica and western Panama late
this week. It is possible that the rains may cause significant
flooding and mudslides in some areas.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 30W, from 19N southward,
moving westward 10 to 15 knots. A 1008 mb low pressure center is
along the wave near 10N. Precipitation: scattered strong is
within 200 nm to 250 nm to the NW of the low pressure center.
Isolated moderate to locally strong is elsewhere within 800 nm to
the SW of 1008 mb low pressure center. Some development of this
system is possible during the next several days, while it moves
west-northwestward, through the eastern tropical Atlantic Ocean,
10 to 15 mph. Upper level winds are forecast to become less
conducive for development by the weekend.

An Atlantic Ocean tropical wave is along 50W, from 19N southward,
moving W 10 to 15 knots. Precipitation: broken to overcast
multilayered clouds, and isolated moderate, are within 440 nm to
the east of the tropical wave, and within 120 nm to the west of
the tropical wave.

A Caribbean Sea tropical wave is along 69W, from 20N southward,
moving W 10 to 15 knots. Precipitation: isolated moderate to
locally strong in clusters is within 425 nm to the east of the
tropical wave, and within 180 nm to the west of the tropical wave.

A tropical wave is along 88W/89W, from the Yucatan Peninsula and
20N southward, moving westward 10 to 15 knots. Precipitation:
numerous strong is in El Salvador. Scattered moderate to widely
scattered strong is within 90 nm on either side of the tropical
wave, from 14N to 16N.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
Senegal near 14N17W, to the 1008 mb low pressure center that is
along the 30W tropical wave, to 05N36W. The ITCZ continues from
05N36W, to 05N38W, to 07N44W. Precipitation: isolated moderate is
within 120 nm on either side of the monsoon trough from 23W
eastward, and within 90 nm to the north of the ITCZ between 42W
and 46W. A surface trough is along 45W/46W from 06N southward.

...GULF OF MEXICO...

Weak upper level cyclonic wind flow is starting to develop in the
north central Gulf of Mexico. A surface trough passes through
southern Alabama and southern Mississippi, curving to northern
Louisiana. Precipitation: isolated moderate spans the Gulf of
Mexico.

The surface pressure pattern is flat and weak. A broad surface
ridge extends from Florida near 29N83W, southwestward, to the
coast of Mexico near 19N96W.

A surface trough will move into the eastern Gulf of Mexico, from
Wednesday night into Thursday morning, bringing fresh N to E
winds. High pressure pressure will dominate the rest of the basin
through Friday, producing mainly gentle to moderate E to SE
winds. Fresh winds will pulse to the west of the Yucatan
Peninsula tonight and again on Wednesday night. A broad area of
low pressure is expected to form in the southwestern Caribbean
Sea in a couple of days. The environmental conditions are
forecast to be conducive for the development of the low if it
remains over water. It is possible for a tropical depression to
form late this week or during the weekend, while the system moves
northwestward through the northwestern Caribbean Sea, across the
Yucatan Peninsula of Mexico, and into the southwestern Gulf of
Mexico by Sunday. It is likely for the wind speeds and the wave
heights to increase in the Gulf of Mexico during the upcoming
weekend.

...CARIBBEAN SEA...

Two tropical waves are in the Caribbean Sea. One is along
69W. The second tropical wave is along 88W/89W. All the
information about each tropical wave and its accompanying
precipitation is in the Tropical Waves section.

An upper level trough passes through the Bahamas, across Cuba,
into the SW corner of the Caribbean Sea. Upper level cyclonic
wind flow covers the Caribbean Sea from the 73W westward.

The eastern extension of the eastern Pacific Ocean monsoon trough
is along 11N74W in Colombia, toward the Colombia/Panama border,
through southern Panama, beyond 08N84W, into the eastern Pacific
Ocean. Precipitation: numerous strong is from 10N to 12.5N between
71W and 74W including in the Peninsula de la Guajira of Colombia,
and in Colombia and Venezuela from 08N to 10N between 72W and 74W.
Numerous strong is in the SW corner of the Caribbean Sea from 10N
to 12N between 76W and 81W. Scattered strong is from 10N to 13N
between 73W and 77W. Widely scattered moderate to isolated strong
is from 14N southward between 80W and 85W including in the SE
Nicaragua. Widely scattered moderate to isolated strong is inland
from Panama to Costa Rica.

Fresh to locally strong trade winds will dominate most of the
eastern and central Caribbean Sea through midweek, with seas in
the range from 7 feet to 9 feet. Fresh to strong winds are
expected in the Windward Passage, and in the lee of Cuba, through
tonight. A broad area of low pressure is expected to form in the
southwestern Caribbean Sea in a couple of days, from a tropical
wave that currently is along 69W. The environmental conditions
are forecast to be conducive for development of the low if it
remains over water. It is possible for a tropical depression to
form late this week or during the weekend, while the system moves
northwestward through the northwestern Caribbean Sea, across the
Yucatan Peninsula of Mexico, and into the southwestern Gulf of
Mexico by Sunday. It is likely for the wind speeds and the wave
heights to increase between 77W and the Yucatan Peninsula on
Friday and Saturday.

...ATLANTIC OCEAN...

An upper level cyclonic circulation center is on top of the
Bahamas. Upper level cyclonic wind flow covers the Atlantic Ocean,
Florida, and the Gulf of Mexico from 20N northward between 64W and
84W. A surface trough is along 70W from 21N to 28N. Precipitation:
widely scattered moderate to isolated strong is from 23N to 30N
between 63W and 78W.

A second upper level cyclonic circulation center is near 20N55W,
about 285 nm to the SW of a 24N51W 1012 mb low pressure center. A
surface trough curves from the 1012 mb low center, northeastward,
to 31N50W, and the southwestern end of a stationary front.
Comparatively drier air in subsidence in water vapor imagery is
within 310 nm of the upper level cyclonic center in the southern
semicircle. Precipitation: widely scattered moderate to isolated
strong is within 240 nm to the east of the surface trough, and
between the upper level cyclonic circulation center and the 24N51W
low pressure center, between 50W and 56W. Little development of
this system is expected during the next day or two, due to
unfavorable upper level winds. The environmental conditions are
expected to become more conducive for development, after the first
48 hours. It is likely for a tropical depression to form by the
end of the week, while the system turns eastward in the central
Atlantic Ocean.

Broad upper level cyclonic wind flow covers the Atlantic Ocean
from 20N northward from 25W eastward.

A surface ridge passes through 33N71W in the Atlantic Ocean, to
29N83W in Florida.

A surface trough, that is just to the east of the Bahamas, is
producing fresh to strong NE winds in the central Bahamas,
reaching the coast of Cuba. This feature will move westward,
bringing fresh to locally strong NE winds to the the NW Bahamas
and SE Florida, including in the Straits of Florida on Wednesday,
before the trough weakens by late Thursday. A 1022 mb high
pressure center that is near Bermuda will dominate the remainder
of the forecast region through at least Wednesday. Fresh to
locally strong winds are expected to pulse to the N of Hispaniola
during the evening hours through Saturday night.

$$
mt/gr
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