610
AXPZ20 KNHC 210824
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 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 0600 UTC surface analysis and satellite imagery through
0810 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 Guatemala and its E Pacific
offshore waters. The wave axis is near 91W and is moving
westward at about 10 kt. Scattered to numerous moderate to strong
convection is noted N of 12N between 87W and 92W.

A tropical wave has its axis along 107W from 06N to 18N, and is
moving westward at 10-15 kt. Scattered moderate convection is
from 09N to 17N between 106W and 116W.

A tropical wave has its axis near 125W from 04N to 16N moving
westward at about 10 kt. Scattered moderate convection is from
08N to 13N between 120W and 130W.

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

The monsoon trough extends from 13N89W to a 1008 mb low near
14N107W to 10N130W to 10N140W. Aside from the convection
associated with the tropical waves described above, numerous
moderate to strong convection is from 03N to 07N E of 79W, and
from 11N to 17N between 98W and 103W. Scattered moderate
convection is from 05N to 10N between 81W and 97W and from 07N to
14N W of 135W.

...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. Along the
Gulf of California, light to gentle winds are ongoing, except for
moderate to locally fresh SW winds in the northern Gulf N of
29N. Light to gentle winds and slight to moderate seas are
elsewhere, except for moderate to locally fresh W winds over the
outer S and SW Mexican 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
tonight, then diminish to gentle to moderate speeds afterward
into Wed night. Ongoing moderate to fresh SW winds in the
northern Gulf of California will diminish to gentle speeds today
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 through Mon. Looking ahead, an area of
low pressure could form well to the SW of the SW 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
N to NE. 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 heavy
showers and tstms are over the majority of the Central America
offshore waters due to an active monsoon trough. Locall y 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 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 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 extending from a pair of high pressure centers
located well NW of the area reaches ESE to just W of 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 and W of
110W. 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 9 ft
are forecast to develop today in association with a 1010 mb low
located near 10N138W. The low will prevail in that region today
and then move W of 140W tonight. Southwest monsoonal winds will
continue to become well established through the remaining weekend
as the monsoon trough lifts slowly northward. Looking ahead, an
area of low pressure could form well to the SW of the SW 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 N to NE. 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