124
AXPZ20 KNHC 220405
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Sun Sep 22 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.

...SPECIAL FEATURE...

A Central American Gyre is gradually developing this weekend and
will continue through the middle of next week. This scenario,
combined with daytime heating and orographic lifting, is expected
to generate periods of excessive rainfall over southern Mexico
and Central America, as well as the adjacent W Caribbean and E
Pacific waters between 80W and 95W. This activity could produce
dangerous flash flooding and mudslides across the area.
Furthermore, strong to near gale force winds, rough seas and
tstms are forecast to affect the offshore waters between Costa
Rica and El Salvador from Mon night through the end of the week.
Please follow the forecasts from your local weather offices for
more detailed information.

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

The monsoon trough extends from 11N86W to 13N100W to 15N106W to
10N130W to 10N140W. Scattered moderate convection is noted N of
05N E of 87W, from 09N to 17N between 97W and 123W, and from 06N
to 13N W of 133W.

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

A broad surface ridge extends SE to just west of the Baja California
offshore waters. Moderate to fresh NW winds prevail over the
Baja California offshore waters with moderate seas. SW to W winds
of the same speed are across the outer offshore wateres of S and
SW Mexico. Light to gentle winds are ongoing along the Gulf of
California with slight seas. Otherwise, light to gentle winds
and slight to moderate seas are elsewhere.

For the forecast, surface ridging will remain in place and
fluctuate through Sun. Moderate to fresh NW winds will continue
over the Baja California offshore waters through early Sun, then
diminish to gentle to moderate speeds afterward into Wed night.
Light to gentle winds will prevail along the Gulf of California
through Thu night. An active monsoon trough will support moderate
to fresh W to SW winds across the outer SW Mexican offshore
waters through Mon. Looking ahead, a trough of low pressure
producing a large area of showers and thunderstorms located a few
hundred miles south of the coast of southern Mexico has the
potential for some slow development while it meanders offshore
the next few days. A tropical depression could form from this
system during the early or middle part of next week when the
system begins to move slowly eastward or northeastward toward the
coast of southern Mexico. Regardless of development, strong to
near-gale force winds and rough seas are forecast to affect the S
and SW Mexican offshore waters starting Mon night and continuing
through the end of the week.

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

Moderate to fresh SW to W winds are ongoing south of the monsoon
trough and across the offshore waters from Colombia to Costa
Rica along with moderate seas. Gentle to moderate winds and
slight to moderate seas prevail elsewhere. Scattered showers and
tstms are over the majority of the Central America offshore
waters due to an active monsoon trough. Strong winds and rough
seas are likely in the regions of strongest convection.

For the forecast, moderate to fresh southwest to west winds
south of the monsoon trough will change little through Mon, then
increase to fresh to near gale force speeds across the offshore
waters from Costa Rica to Guatemala late Mon through Wed night.
Seas will build during this time in mixed swell. The monsoonal
flow is expected to become very active, and dominate the region
through next week. This pattern will generate increasing westerly
wind waves moving into the area waters. Periods of very active
weather are also expected across the Central America offshore
waters through at least mid week.

...REMAINDER OF THE AREA...

Surface ridging prevails N of 20N and W of 120W. The pressure
gradient between the ridge and the monsoon trough to the south is
resulting in moderate to fresh NE trade winds and moderate seas
from 12N to 22N and W of 130W. An area of fresh to strong winds
and seas to 9 ft prevails along the monsoon trough from 10N to
15N between 107W and 115W. Gentle to moderate NE to E winds and
moderate seas are noted elsewhere N of the monsoon trough.

For the forecast, southwest monsoonal winds will continue to
become well established through early next week as the monsoon
trough lifts slowly northward. Looking ahead, an area of low
pressure could form well to the southwest of the southwestern
coast of Mexico during the next couple of days. Environmental
conditions appear conducive for some slow development of this
system, and a tropical depression could form during the early or
middle part of next week while the system moves slowly eastward
or northeastward. Regardless of development, strong to near-gale
force winds and rough seas are forecast to affect the S and SW
Mexican offshore waters and adjacent open waters starting Mon
night and continuing through the end of the week.

$$
Ramos