245
AXPZ20 KNHC 210402
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Sat Sep 21 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
0320 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 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 mid week. Please follow the
forecasts from your local weather offices for more detailed
information.

...TROPICAL WAVES...

A tropical wave moves across the Yucatan Peninsula, Guatemala and
its E Pacific offshore waters. The wave axis is near 90W and is
moving westward at about 10 kt. Scattered moderate convection is
noted from 06N to 15N between 83W and 97W.

A tropical wave has its axis along 107W from 05N to 18N, and is
moving westward at 10-15 kt. Scattered moderate isolated strong
convection is from 09N to 16N between 100W and 114W.

A tropical wave has its axis along 124W from 04N to 16N moving
westward at about 10 kt. Scattered moderate convection is from
09N to 14N between 114W and 127W.

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

The monsoon trough extends from 10N85W to a 1007 mb low near
14N107W to 09N130W to 10N137W. The ITCZ continues from 10N138W
and then beyond 10N140W. Aside from the convection associated
with the tropical waves described above, scattered moderate
convection is N of 03N and E of 83W. Scattered moderate
convection is also from 07N to 14N W of 135W.

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

A broad surface ridge extends southeastward into the region.
Moderate to fresh northwest winds are over the Baja California
offshore waters with 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 slight seas are elsewhere, except for
moderate to locally fresh W winds over the outer southern Mexico
offshore waters.

For the forecast, the surface ridge will remain in place and
fluctuate into the weekend. Moderate to fresh NW winds will
continue over the Baja California offshore waters 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 Wed night. An active monsoon trough will
support moderate to fresh W to SW winds across the outer SW
Mexican offshore waters tonight through Tue night. Looking ahead,
an area of low pressure could form well to the southwest of the
southwestern coast of Mexico this weekend. Environmental
conditions appear conducive for some slow development of this
system, and a tropical depression could form during the next few
days while it slowly moves generally north to northeastward.
Regardless of development, strong to near-gale force winds and
rough seas are forecast to affect the S and SW Mexican offshore
waters starting Tue evening 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 southwest to west 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 moderated seas prevail elsewhere. Scattered
heavy showers are over the majority of the Central America
offshore waters.

For the forecast, moderate to fresh southwest to west winds
south of the monsoon trough will change little through the
weekend, 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 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
the Central America offshore waters through mid week.

...REMAINDER OF THE AREA...

Surface ridging extending from a pair of high pressure centers
located well NW of the area reaches ESE to the Baja California
Peninsula offshore waters and south to about 20N. 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 10N to 20N and W of 132W. Gentle to moderate NE to E winds
and moderate seas are elsewhere N of 10N. South of the monsoon
trough and between 102W and 120W SW winds are fresh to strong and
seas are 7-8 ft. Between 82W and 102W, SW winds are moderate to
fresh and seas are 5-7 ft.

For the forecast, fresh to strong winds and rough seas to 10 ft are
forecast to develop tonight in association with a 1010 mb low
located near 10N138W. The low will prevail in that region Sat and
then move W of 140W Sat night. SW monsoonal winds will continue
to become well established through the weekend 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 this weekend. Environmental conditions appear
conducive for some slow development of this system, and a
tropical depression could form during the next few days while it
slowly moves generally north to northeastward. Regardless of
development, strong to near gale force SW to W winds will develop
and amplify, covering the open waters between 90W and 110W Mon
night through Wed night.

$$
Ramos