980
AXPZ20 KNHC 181802 CCA
TWDEP

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
1605 UTC Wed Sep 18 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 1200 UTC surface analysis and satellite imagery through
1545 UTC.

...TROPICAL WAVES...

A western Caribbean tropical wave is along 81W/82W and extends
southward across Panama and into the eastern Pacific waters north
of 05N, moving westward at 10 kt. Scattered moderate to isolated
strong convection is within 120 nm either side of the southern
part of the wave from 06N to 08N.

A tropical wave is along 95W extending from the Isthmus of
Tehuantepec southward over the eastern Pacific waters to near
04N, moving westward at about 10 kt. Scattered moderate to
isolated strong convection is within 180 nm west of the wave
from 07N to 10N and from 12N to 15N. Similar activity is within
180 nm east of the wave from 10N to 13N.

A tropical wave is along 112W from 19N to near 06N, moving
westward at 10 to 15 kt. Scattered moderate convection is
within 120 nm west of the wave from 12N to 16N.

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

The monsoon trough axis extends from northern Colombia to 10N85W
to 11N100W to 10N113W to 09N125W to 09N131W, where it
transitions to the ITCZ and continues to 09N131W to beyond
10N140W. Scattered moderate to isolated strong convection is
within 180 nm of the trough between 97W and 104W, within 180 nm
south of the trough between 78W and 84W, and within 120 nm south
of the trough between 123W and 129W. Scattered moderate
convection is within 120 nm north of the trough between 120W and
123W.

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

A broad surface ridge extends southeastward into the region
through 30N129W to offshore of Cabo Corrientes near 17N107W.
Over the near and offshore waters of the Baja California
peninsula, moderate NW winds prevail, except for strong winds
along the coast between Punta Eugenia and Cabo San Lazaro. Seas
are 4 to 6 ft in moderate period swell except 6 to 7 ft in the
areas of strong winds. Moderate NW to N winds prevail elsewhere
to the south across the Revillagigedo Islands, while moderate NW
winds are across the near shore waters from Cabo Corrientes to
Manzanillo. Light to gentle NW to W winds cover the remaining
waters eastward to Tehuantepec. Seas south of 20N are 4 ft in
long period SW swell. Scattered showers and thunderstorms moving
westward are over the waters SW of the Gulf of Tehuantepec and
Chiapas. This activity is noted from 11N to 15N between 93W and
100W. Light to gentle S to SW winds are over the northern part
of the Gulf of California while gentle SW to W winds are over
the southern part of the Gulf, and light and variable winds are
over the central portion. Seas are 1 to 3 ft over the Gulf of
California, except to 6 ft in SW swell over the entrance to the
Gulf.

For the forecast, the current Pacific ridge will remain in place
and fluctuate throughout the week. This pattern will maintain
moderate to fresh NW to N winds over the offshore waters of the
Baja California peninsula, gradually weakening through Thu.
Expect fresh winds near the coast each evening through Sat. 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 W gap winds across southern portions and fresh SW gaps
winds N of 30N each evening and night.

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

Gentle to moderate SW to W winds are occurring south of the
monsoon trough tonight, along about 10N. North of the monsoon
trough, moderate or weaker winds are observed, with moderate
easterly gap winds flowing across the Papagayo region. Seas are
4 to 5 ft in SW swell except to 6 ft south through west of the
Galapagos Islands. Increasing scattered to numerous showers and
thunderstorms are within 90 nm of the coasts of Panama, Colombia
and southern Costa Rica.

For the forecast, gentle to moderate SW to W winds will continue
south of the monsoon trough near 10N through tomorrow afternoon,
then begin to freshen offshore Thu through Sat. Seas will build
to 5 to 7 ft during this time in a mix of SW swell and westerly
wind swell. Active weather is expected south of 10N Fri into the
weekend. North of 10N, moderate or weaker winds are expected
through Thu evening before the monsoon trough begins to lift
northward, and winds shift to westerly and gradually increase to
gentle to moderate by Sat. Seas will build slightly across the
area waters Thu through Sat as a long fetch of westerly winds
sets up from offshore to 110W, and generates increasing wind
waves moving into the area waters.

...REMAINDER OF THE AREA...

Surface ridging extending from a 1030 mb high centered near
38N157W extends east-southeastward to 30N129W to offshore of
Cabo Corrientes near 17N107W. The pressure gradient between the
ridge and the ITCZ/monsoon trough to the south is forcing
moderate to locally fresh NE trades south of 28N and west of
125W, with strongest from 10N to 19N west of 135W. Seas are
6 to 8 ft in mixed swell south of 17N west of 133W, and 4 to 6 ft
elsewhere.

For the forecast, little overall change is expected over the
open Pacific waters for the next several days, as the ridge
dominates the region. A weak cold front will sink southward
across 30N east of 130W Wed night, 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 Sat. SW to W monsoonal winds are
expected to become well established south of 10N and east of
120W late Wed through Sat, becoming moderate to fresh. Seas will
build to 6 to 8 ft from 03N to 11N east of 120W during that
time.

$$
Aguirre