[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180555
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Fri Aug 18 2023

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 FEATURES...

Eastern Tropical Atlantic (AL98):
Showers and thunderstorms continue to show some signs of
organization in association with a broad area of low pressure
located a few hundred miles west of the Cabo Verde Islands.
Environmental conditions appear generally favorable for
additional development of this system, and a tropical depression
is likely to form over the weekend while it moves toward the
west-northwest or northwest at about 10 kt across the eastern
tropical Atlantic. By early next week, upper-level winds over
the system are forecast to increase, and further development is
not expected. This system has a medium chance of tropical
cyclone development within 48 hours.

Central Tropical Atlantic (AL99):
An elongated trough of low pressure located more than 1000 miles
west-southwest of the Cabo Verde Islands is producing some
disorganized showers and thunderstorms. Environmental conditions
are only marginally conducive for further development of this
system, but a tropical depression could still form during the
next couple of days while it moves west-northwestward at 10 to
15 mph across the central tropical Atlantic. Thereafter, upper-
level winds are forecast to become unfavorable for any further
development.This system has a medium chance of tropical cyclone
development within 48 hours.

Please refer to the latest NHC Tropical Weather Outlook at
www.hurricanes.gov for more details on both special features.

...TROPICAL WAVES...

Please see the SPECIAL FEATURES section above for information on
a tropical wave near 30W that has induced low pressure formation
and that has a potential for tropical development and on a
central Atlantic area of low pressure with a low near 12N40W.

A western Atlantic tropical wave has its axis near 50W from 06N
to 19N. It is moving westward near 15 kt. Scattered moderate and
isolated strong convection is depicted from 07N to 14N between
48W and 55W.

A Caribbean tropical wave has its axis near 73W, or from the
western part of Haiti  to just inland Colombia. It is moving
westward around 13 kt. The wave has helped to set off scattered
to numerous moderate convection over parts of Colombia.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis enters the Atlantic near 18N17W and
continues to 17N22W to a low pressure near 15N29W, to a low
pressure near 13N41W, and ends near 11N54W. Outside of
convection associated to the SPECIAL FEATURES and TROPICAL
WAVES, scattered moderate convection south of the trough
is depicted between 18W and 21W.

GULF OF MEXICO...

A weak surface trough extends across Florida and is producing
scattered moderate convection in the nearshore and offshore
waters of southwest Florida and the Florida Keys. Another
surface trough is located near the Campeche Bay. However, no
significant convection is depicted in association with this
trough. Otherwise, high pressure prevails across the Gulf
waters, with a weak pressure gradient supporting light to gentle
winds and seas of 1 to 2 ft.

For the forecast, a surface ridge over the Gulf waters will
support mostly gentle to moderate winds and slight seas across
the basin through Sat night. Looking ahead, a surface trough is
expected to move across the Gulf from east to west Sun through
early next week. The trough could form into a broad area of low
pressure in the central or W Gulf by the beginning of next week.
Some slow development of this system is possible thereafter as
it moves westward and approaches the western Gulf of Mexico
coastline by the middle of next week.

CARIBBEAN SEA...

Scattered showers and thunderstorms are depicted in the
southwestern Caribbean Sea near the offshore waters of Panama,
Costa Rica, and Nicaragua in association with the eastern end of
the Pacific Monsoon Trough. Elsewhere, no significant convection
is depicted at this time.

The pressure gradient between the subtropical ridge in the
central Atlantic and low pressure over NW Colombia is supporting
fresh easterly trade winds in the south central Caribbean.
Moderate to locally fresh winds are over the north central and
eastern Caribbean. Gentle to moderate winds are in the western
Caribbean. Seas are in the 5 to 6 ft range in the central
Caribbean, with 3 to 5 ft seas elsewhere, except for lower seas
of 2 to 4 ft seas in the NW basin.

For the forecast, moderate to fresh trade winds will prevail
over the eastern and central Caribbean during the next few days.
A strong tropical wave is likely to approach the E Caribbean
this weekend and spread fresh to strong winds and building seas
over the NE Caribbean Sat night into Tue.

ATLANTIC OCEAN...

Please refer to the SPECIAL FEATURES and the MONSOON TROUGH/ITCZ
sections above for details on the two low pressure systems in
the central and eastern Atlantic that could become tropical
cyclones. And convection in the tropical Atlantic. A weak
surface trough off the coasts of east Florida is producing
isolated moderate convection near the western Bahamas.

An expansive subtropical ridge dominates the tropical and
subtropical Atlantic waters N of 20N. Fresh to locally strong
winds, and seas of 7 to 9 ft, are noted from 15N to 24N between
35W and 74W. Gentle to moderate winds, and seas of 4 to 6 ft are
noted elsewhere. The exception is a zone of fresh to locally
strong south-southwest winds north of 29N, ahead of a stationary
front that extends from the southeastern U.S. to just along the
coast of Louisiana and northwestward from there to eastern
Texas.

For the forecast W of 55W, Fresh to locally strong tradewinds
will pulse off Hispaniola each evening into early next week.
Fresh tradewinds south of 25N today will persist through Sat. A
strong tropical wave could enhance winds and seas near the
Leeward and Virgin Islands over the weekend, and north of Puerto
Rico early next week.

$$
KRV
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