311
AXPZ20 KNHC 200940
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 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 0600 UTC surface analysis and satellite imagery through
0930 UTC.

...TROPICAL WAVES...

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

A tropical wave has its axis along 103W from 05N to 17N. It is
moving westward at 10 to 15 kt. Scattered moderate convection is
from 08N to 15N between 96W and 107W.

A tropical wave has its axis along 121W from 06N to 18N moving
westward at about 10 kt. Scattered moderate convection is from
07N to 15N between 119W and 127W.

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

The monsoon trough axis extends from northwest Colombia to
12N87W to 13N109W to 09N125W. Aside from the convection
associated with the tropical waves, scattered moderate to
isolated strong convection is from 08N to 16N between 106W and
118W. Scattered moderate convection is from 06N to 14N west of
131W.

...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 weekend. Gentle to moderate northwest to north
winds over the Baja California offshore waters will increase to
fresh speeds this 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 to near gale force winds and rough seas are
forecast to affect the outer offshore waters SW of Cabo San Lucas
starting Mon night and continuig beyond mid 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 Central America offshore waters
S of 10N. Seas are 4 to 6 ft in south to southwest swell. In the
Papagayo region, moderate to fresh NE to E winds are ongoing
along with moderate seas. Gentle to moderate SE to S winds are
observed between the coast of Ecuador and the Galapagos Islands.
Otherwise, heavy showers and thunderstorms are over the majority
of the Central America offshore waters, except scattered showers
in the Gulf of Panama. Seas are up to 10 ft in the areas of
strongest convection offshore Costa Rica.

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 today 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 the 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 to the Baja
California Peninsula offshore waters. The pressure gradient
between the ridge and the monsoon trough to the south is
resulting in moderate to locally fresh NE trade winds and
moderate seas south of about 24N and west of 130W. South of the
monsoon and a 1008 mb low near 13N109W winds are fresh to strong
from the SW and seas are 7 to 8 ft in long-period southeast
swell. Seas are 5 to 6 ft in long-period southerly swell
elsewhere S of the monsoon.

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. 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