274
AXPZ20 KNHC 200406
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Fri Sep 20 2024

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 0000 UTC surface analysis and satellite imagery through
0350 UTC.

...TROPICAL WAVES...

A tropical wave over the far western Caribbean has its axis near
87W. It extends southward across central Honduras, western
Nicaragua to just west of Costa Rica and reaches to the eastern
Pacific near 05N. It is moving westward at about 10 kt. Numerous
moderate to strong convection and tstms are affecting the
offshore waters from Nicaragua to western Panama.

A tropical wave has its axis along 102W from 03N to 17N. It is
moving westward at 10 to 15 kt. Scattered moderate to isolated
strong convection is from 07N to 15N between 96W and 106W.

A tropical wave has its axis along 120W from 05N to 18N moving
westward at about 10 kt. Scattered moderate convection is from
08N to 16N between 115W and 127W.

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

The monsoon trough axis extends from northwest Colombia to
13N89W to 13N107W to 09N124W. Aside from the convection
associated with the tropical waves, scattered moderate to
isolated strong convection is from 08N to 16N between 106W and
114W. Scattered moderate convection is from 06N to 13N west of
132W.

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

A broad surface ridge extends southeastward into the region.
Gentle to moderate northwest to north winds are over the Baja
California offshore waters with slight to moderate seas. Along
the Gulf of California, light to gentle winds are ongoing, except
for moderate to fresh SW winds in the northern Gulf N of 29N.
Light to gentle winds and moderate seas are elsewhere.

For the forecast, the Pacific ridge will remain in place and
fluctuate into the upcoming weekend. Gentle to moderate northwest
to north winds over the Baja California offshore waters will
increase to fresh speeds Fri evening and continue through late
Sat night, then diminish to gentle to moderate speeds afterward
into Mon night. Ongoing moderate to fresh SW winds in the
northern Gulf of California will diminish to gentle speeds Sat
and then prevail through Tue night. An active monsoon trough will
support mainly moderate to fresh W to SW winds across the outer
SW Mexican offshore waters Fri night through Tue night. Looking
ahead, an area of low pressure could form well to the southwest
of the SW coast of Mexico late this weekend. Environmental
conditions appear conducive for some slow development of this
system thereafter as it slowly moves generally northward.
Regardless of development, strong winds and rough seas are
forecast to affect the outer offshore waters SW of Cabo San Lucas
by late Tue.

...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. North of the monsoon trough, moderate or weaker
winds are observed. Seas are 4 to 6 ft in long-period south to
southwest swell. Heavy showers and thunderstorms are over the
majority of the Central America offshore waters, except scattered
showers in the Gulf of Panama.

For the forecast, moderate to fresh southwest to west winds
south of the monsoon trough will change little through Sun night,
then increase to fresh to strong speeds across the offshore
waters from Costa Rica to Guatemala Mon through Tue night. Seas
will build during this time in a mix of southwest swell and
westerly wind swell. The monsoonal flow is expected to become
very active, and dominate the region Fri into early next week.
This pattern will generate increasing westerly wind waves moving
into the area waters. Periods of very active weather are also
expected across area waters north of 06N through the weekend and
possibly into next week.

...REMAINDER OF THE AREA...

Surface ridging extending from a 1027 mb high that is centered
well northwest of the area extends east-southeastward through
27N130W to offshore of SW Mexico. The pressure gradient between
the ridge and the monsoon trough to the south is resulting in
moderate northeast trade winds south of about 24N 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 in long- period southeast
swell south of the monsoon trough from 03N to 10N between 90W and
120W, and 4 to 6 ft in long-period southerly swell elsewhere as
noted in recent altimeter satellite data passes.

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
frontal trough extends from southeastern California
southwestward to far northern Baja California and to
near 30N120W. Latest ASCAT satellite data passes indicate
light to gentle northwest winds near the trough. Southwest to
west monsoonal winds will continue to become well established
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
generally develop from 05N to 12N and east of 120W through the
weekend. Seas within this wind regime will build to around
7 to 10 ft east of 120W during that time.

$$
Ramos