276
AXNT20 KNHC 210854
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sat Sep 21 2024

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
0930 UTC.

...SPECIAL FEATURES...

Potential Heavy Rainfall in Central America:
A Central American Gyre (CAG) is forecast to gradually develop
over Central America this weekend, possibly near Costa Rica and
Panama this weekend. It will slowly drift NW across Nicaragua,
Honduras, and the Yucatan Peninsula through the middle of next
week. Aided by abundant tropical moisture already in the region,
this system may produce significant rainfall near Panama this
weekend, then Costa Rica and eastern Nicaragua late this weekend
through early next week. Afterward, heavy rain may spread over
central and northern Guatemala and western Honduras during the
first half of next week, and into Belize and the Yucatan Peninsula
late next week. This will lead to an increased potential for life-
threatening flash flooding and mudslides in these areas. It is
recommended that residents in the aforementioned areas stay alert
on the latest information from their local meteorological
agencies. Please refer to the Tropical Weather Discussion for the
Eastern Pacific at website:
https://www.hurricanes.gov/text/MIATWDEP.shtml for rainfall across
El Salvador and the Pacific coasts of Nicaragua, Guatemala, and
southern Mexico.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic along the coast of Gambia,
then extends southwestward through 10N29W to 08N35W. An ITCZ then
stretches from 08N35W to 10N51W. Scattered moderate convection is
noted near and south of the trough from 06N to 14N between the
central Africa coast and 18W.

The eastern end of the East Pacific monsoon trough is producing
numerous moderate to isolated strong convection across the
Caribbean waters near northwestern Colombia.

...GULF OF MEXICO...

Convection associated with a weak surface trough over the Florida
Straits has dissipated overnight, with high pressure of 1012 mb
centered along the Mississippi coast dominating Gulf weather and
leading to dry conditions. Gentle E winds and seas of 1 to 3 ft
prevail.

For the forecast, high pressure will dominate into early next
week. A broad area of low pressure may form by the early to middle
portions of next week over the NW Caribbean and adjacent portions
of Central America. Thereafter, gradual development of this
system is possible, and a tropical depression could form as the
system moves slowly to the north or northwest over the
northwestern Caribbean Sea and into the southern Gulf of Mexico
through the end of next week. There is a medium chance of tropical
cyclone formation in the next seven days. Regardless of
development, winds and seas will start increasing across the SE
Gulf early next week.

...CARIBBEAN SEA...

Please refer to the SPECIAL FEATURES section above for potential
heavy rainfall and already increasing convection associated with
a developing Central American Gyre (CAG). Refer to the Monsoon
Trough/ITCZ section for additional convection in the Caribbean
Sea.

Gentle to moderate E to SE winds and seas at 3 to 5 ft are
present across the south- central and southeastern basin. Gentle
E winds and seas of 2 to 4 ft prevail elsewhere in the Caribbean
Sea.

For the forecast, moderate to fresh winds and moderate seas are
expected across the E and central Caribbean through tonight.
Looking ahead, a broad area of low pressure could form by the
early to middle part of next week over the northwestern Caribbean
Sea and adjacent parts of Central America. Thereafter, gradual
development of this system is possible, and a tropical depression
could form as the system moves slowly to the north or northwest
over the northwestern Caribbean Sea and into the southern Gulf of
Mexico through the end of next week. There is a medium chance of
tropical cyclone formation in the next seven days.

...ATLANTIC OCEAN...

See the Monsoon Trough/ITCZ section above for details on
convection in the eastern Tropical Atlantic offshore Africa.

Low pressure of 1008 mb centered near 25N55W is inducing
scattered moderate convection within about 90 nm of the center in
the NE quadrant, along with fresh winds and seas to 7 ft within
about 180 nm of the center in the NE semicircle. Environmental
conditions do not appear conducive for significant development of
this system during the next couple of days while it drifts
northwestward over the central or western subtropical Atlantic.

To the east, another low pressure of 1005 mb, the remnants of
Tropical Storm Gordon, is centered near 26N42W. This low is
inducing scattered moderate convection E of the center, from 23N
to 30N, extending E to 32W. Within this area of scattered showers
and thunderstorm, fresh to locally strong winds and seas to 8 ft
prevail. The precipitation is being sheared away from the center
by strong upper level winds, and these winds are forecast to
prevent significant development of this low as it meanders over
the central subtropical Atlantic during the next couple days.

Elsewhere, a surface trough stretches from around 31N73W, across
the NW Bahamas, and into the Florida Straits. This trough is
leading to scattered moderate convection over the central and NW
Bahamas. Gentle to moderate NE winds are noted NW of this trough
axis. Other areas of central to moderate winds are noted within
about 150 nm of the South American coast as well as in the
vicinity of the Cabo Verde Islands, extending E to the coast of
Africa. Elsewhere in the basin, winds are light to gentle. Seas
aside from the areas already mentioned average 3 to 6 ft.

For the forecast W of 55W, a weak cold front will exit the
southeast coast of the US tonight and slowly move across the
waters north of 25N into Mon night.

$$
Konarik