915
AXNT20 KNHC 182306
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Thu Sep 19 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 1800 UTC surface analysis and satellite imagery through
2245 UTC.

...SPECIAL FEATURES...

Central Atlantic Significant Swell Event: A stationary front
extends from 31N65W southeastward to 26N61W and to low pressure
of 1008 mb near 27N52W. A recent ASCAT satellite data pass
revealed strong to near gale-force winds within 300 N semicircle
of the low. Seas are 9 to 13 ft with these winds. Satellite
imagery shows scattered moderate convection east-northeast of
the low near 26N53W. The low near 26N53W will shift west-
southwestward through Fri allowing for a slackening of the tight
pressure gradient to its north. This will result in winds
diminishing and seas to subside below 12 ft.

Please see the latest NWS High Seas Forecast issued by the
National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for further details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave has its axis 33W from 05N to
20N. It is moving westward near 10 kt. Isolated light showers
are near the southern part of the wave.

A western Caribbean tropical wave has its axis along 83W south
of 20N to eastern Pacific waters south of the Costa Rica/Panamanian
border. It is moving westward at 5 to 10 kt. Numerous moderate
convection is within 240 nm east of the wave from 12N to 16N.
Numerous moderate to isolated strong convection is west of the
wave inland Central America.

The northern portion of an eastern Pacific tropical wave extends
northward along an axis along 96W to inland southeastern Mexico
near 18N. No significant convection is noted over land. This
wave will be described in subsequent East Pacific Tropical
Weather Discussions.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends through the coastal plains of
Senegal near 14N17W west-southwestward to 13N25W to 12N35W and
to 13N46W. No significant convection is noted.

...GULF OF MEXICO...

The 18Z analysis suggests that a rather weak pressure pattern is
in place over the area allowing for light to gentle winds and
slight seas across much of the basin, except for gentle to
moderate east to southeast winds over the eastern Bay of
Campeche. A mid to upper-level trough over the eastern Gulf is
helping to keep a few showers and thunderstorms active near some
sections of the Florida coast.

For the forecast, the weak pressure pattern that is place will
change little through the upcoming weekend maintaining little
change with current winds and seas. Moderate winds may pulse in
the eastern Bay of Campeche nightly through the next several
days. A cold front is forecast to clip the far northeast waters
Thu into Fri with little change in winds and seas. Winds may
increase across the southeastern Gulf by Mon as low pressure
forms over the northwestern Caribbean.

...CARIBBEAN SEA...

The tail-end of a through stretches southwestward from the
remnant low of Gordon to the far southeastern Caribbean to just
north of Margarita Island. Scattered showers and a few
thunderstorms are along and near the trough. An area of numerous
moderate convection is over the western Caribbean from 11N to 15N
between 78W and 82W. Isolated showers and thunderstorms are
elsewhere south of 17N and west of 78W. Partial ASCAT satellite
data passes indicate mostly moderate trades over the central
section of the sea along with some patches of trades of fresh
speeds, gentle to moderate east to southeast trades over the
northwest and north-central sections, and gentle to moderate
trades over the eastern half of the basin. Seas are in the range
of 2 to 4 ft, except for higher seas of 4 to 6 ft north of 15N
between 68W and 80W, and seas of 3 to 5 ft from 15N to 18N
between 80W and 85W and near the approaches to the Windward
Passage.

For the forecast, the weak pressure gradient that is presently
over the basin will support moderate to fresh winds and moderate
seas across the eastern and central Caribbean sections, and
light to gentle winds along with slight to moderate seas across
the northwestern and southwestern sections of the basin through
at least Sat. Looking ahead, a broad area of low pressure could
form late this weekend or early next week over the northwestern
Caribbean Sea. Thereafter, some slow development of this system
is possible through the middle of next week while it moves slowly
to the north or northwest over the northwestern Caribbean Sea or
the southeastern Gulf of Mexico. There is a low chance of
tropical cyclone formation in the next seven days.

...ATLANTIC OCEAN...

Please read the Special Features section for details about the
ongoing Central Atlantic Significant Swell Event.

A sharp upper-level trough over the southeastern United States
in combination with abundant available moisture continues to
support scattered showers and isolated thunderstorms west of
a line from near 31N67W to 27N72W and to 23N78W. A weakening
stationary front extends from near 31N75W to along the central
Florida coast near Cape Canaveral. A stationary front is
analyzed from 31N65W southeastward to 26N61W and to low pressure
of 1008 mb near 27N52W. Another stationary front extends from
the low northeastward to 29N46W and to north of the area near
31N37W. A large area of numerous moderate to strong convection
is south of the stationary boundary from 24N to 28N between 40W
and 45W. Scattered moderate convection is within 60 nm south of
the same stationary boundary between 45W and 49W. To the SE, low
pressure of 1009 mb, the remnant low of Gordon, is located near
21N49W. A trough extends from the low southwestward to 15N55W
and to the far southeastern Caribbean Sea near northeast
Venezuela. Isolated showers and thunderstorms are within 240 nm
east of the trough from 13N to 16N, and also from 14N to 19N
between the trough and 43W. Relatively weak high pressure covers
the basin between the aforementioned frontal boundaries as a
weak 1015 mb high center is analyzed near 24N68W.

Moderate to fresh southwest winds are within 180 nm east and
southeast of the trough that extends from the remnant low of
Gordon. Seas with these winds are 5 to 6 ft. Elsewhere over the
central and western portions of the basin, fresh east winds are
along the coast of Hispaniola. Fresh north to northeast winds are
west of the Special Features mentioned 1008 low pressure that is
near 26N52W. These winds are noted from 24N to 26N between 54W
and 58W. Seas with these winds are 8 to 10 ft in northeast swell.
Seas elsewhere over the central and western portions of the
basin are 4 to 6 ft, except for higher seas of 6 to 8 ft in
northeast swell from 22N to 24N between 55W and 60W and lower
seas of 3 to 5 ft in northeast swell over waters east of
northern Florida to near 70W.

For the forecast W of 55W, conditions associated to the 1008 mb
low near 27N52W will gradually diminish through Fri. Expect
pulsing fresh trades off the coast of Hispaniola tonight.
Otherwise, gentle to moderate winds and slight to moderate seas
will prevail across the remainder of the basin through the rest
of the week.

$$
Aguirre