861
AXPZ20 KNHC 192002 CCA
TWDEP

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
1605 UTC Thu Sep 19 2024

Corrected Tropical Waves section

Tropical Weather Discussion for the eastern Pacific Ocean from
03.4S to 30N, east of 120W including the Gulf of California, and
from the Equator to 30N, between 120W and 140W. The following
information is based on satellite imagery, weather observations,
radar, and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1545 UTC.

...TROPICAL WAVES...Corrected

A western Caribbean tropical wave has its axis along 84W. It
extends southward across eastern Honduras, eastern Nicaragua,
northern Costa Rica and reaches to the eastern Pacific near 05N.
It is moving westward at 5 to 10 kt. Scattered moderate to
isolated strong convection is within 180 nm west of the wave from
07N to 10N, and within 120 nm east of the wave from 08N to 09N.

A tropical wave has its axis along 100W from 04N to 18N. It is
moving westward at 10 to 15 kt. Scattered moderate to isolated
strong convection is within 180 nm west of the wave from 13N to
18N, and within 180 nm east of the wave from 12N to 15N.

A tropical wave has its axis along 117W from 04N to 20N moving
westward at about 10 kt. Scattered moderate to isolated strong
convection within 180 nm east and west of the wave from 08N to
13N.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

The monsoon trough axis extends from northwest Colombia to
11N86W to 12N102W to 10N119W to 09N125W to 10N140W. Numerous
moderate to strong convection is noted from 10N to 14N between
91W and 97W. Scattered moderate to isolated strong convection is
within 60 nm of the trough between 123W and 126W, and within 60
nm south of the trough between 126W and 131W. Scattered moderate
convection is within 60 nm either side of the trough west of
135W.

...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A broad surface ridge extends southeastward into the region
through 27N130W to offshore of southwestern Mexico near 17N108W.
Gentle to moderate northwest to north winds are over the
offshore waters of Baja California. Gentle northwest to north
are south and southwest of Baja California, including the
vicinity of the Revillagigedo Islands and east-southeastward
from there to the coasts of Jalisco and Michoacan, Mexico. Seas
are generally 4 to 5 ft in moderate period northwest swell. Light
to gentle southwest to west winds are over the remaining waters
eastward to Tehuantepec. Seas south of 20N are to 4 to 5 ft in
long-period southwest swell east of 105W, and in long-period
northwest swell west of 105W. Increasing numerous showers and
thunderstorms are evident offshore the coast and over the coastal
waters within about 180 nm of the Mexican coast between
Tehuantepec and Colima. Gentle to moderate south to southwest
winds are over the northern and central portions of the Gulf of
California. Light to gentle variable winds are over the southern
part of the, except for gentle to southwest to west winds north
of 25N. Seas are 1 to 3 ft over the Gulf of California, except 3
to 4 ft in southwest swell over the entrance to the Gulf.

For the forecast, the current Pacific ridge will remain in place
and fluctuate into the upcoming weekend This pattern will
maintain moderate northwest to north winds over the offshore
waters of Baja California through the rest of this morning,
gradually weakening this afternoon. Expect fresh winds near the
coast each evening. High pressure will strengthen modestly Fri
and Sat to bring a return to moderate to fresh winds. Variable
winds less than 15 kt are expected across the Gulf of California,
except for pulses of moderate west gap winds across southern
portions and fresh southwest gap winds north of 30N each evening
and night through Fri.

...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...

Gentle to moderate southwest to west winds prevail south of the
monsoon trough, along about 10N-11N. North of the monsoon trough,
moderate or weaker winds are observed. Seas are 4 to 5 ft in SW
swell except to 6 ft south through west of the Galapagos Islands.
Scattered to numerous showers and thunderstorms are over the
coast of Costa Rica and over the majority of the Panamanian
coast.

For the forecast, gentle to moderate southwest to west winds
will continue south of the monsoon trough near 11N, through this
afternoon, then begin to freshen offshore through Sat. Seas will
build to 5 to 7 ft during this time in a mix of southwest swell
and westerly wind swell. North of 11N, moderate or weaker winds
are expected through this evening before the monsoon trough
begins to lift northward, and winds shift to westerly and
gradually increase to gentle to moderate by Sat. The monsoonal
flow is expected to become very active, and dominate the region
into early next week, as a long fetch of westerly winds sets up
from the offshore waters to 110W. This pattern will generate
increasing westerly wind waves moving into the area waters.
Active weather is also expected across area waters N of 06N Fri
through the weekend.

...REMAINDER OF THE AREA...

Surface ridging extending from a 1029 mb high that is centered
well northwest of the area near 40N156W extends east-southeastward
through 27N130W to offshore of SW Mexico near 17N108W. The
pressure gradient between the ridge and the monsoon trough to the
south is resulting in moderate northeast trade winds south of
about 25N and west of 130W. Seas are 5 to 6 ft in mixed northeast
and southeast swell south of 25N west of 125W, 5 to 8 ft south
of the monsoon trough from 03N to 10N between 90W and 120W, and
4 to 5 ft in long-period south to southwest swell elsewhere.

For the forecast, little overall change is expected over the
open Pacific waters west of 120W for the next several days as
the aforementioned ridge dominates the region. A dissipating cold
front that stretches from southeastern California to far
northern Baja California and southwestward to 30N121W and to
30N130W will continue to push southward today, then push
southeastward before dissipating by Fri morning. This will induce
a slight decrease in winds during that time period, with winds
then increasing slightly Fri through Sun. Southwest to west
monsoonal winds are expected to become well established this
afternoon through the weekend, as the monsoon trough lifts very
slowly northward. Moderate to fresh southwest to west winds, with
small areas of locally strong winds near active thunderstorms,
will develop from 05N to 12N and east of 120W tonight through the
weekend. Seas within this wind regime will build to 6 to 9 ft
east of 120W during that time.

$$
Aguirre