853
AXPZ20 KNHC 150404
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Wed Oct 15 2025

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
0345 UTC.

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

The monsoon trough axis extends from northern Colombia to
along the coast of central Panama and west-northwestward to
across northern Costa Rica, and continues northwestward to
low pressure, Invest EP91, near 12N94W 1008 mb to 09N105W to
11N114W and to 08N124W, where it transitions to the ITCZ to
09.5N135W to 10N140W. Scattered moderate convection is seen
from 06N to 10N between 94W and 102W.

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

A trough extends from SW Arizona southwestward to across the
northern Gulf of California while broad high pressure is west
of the Baja California peninsula ahead of a cold front that
extends from near 30N119W to 28N126W to near 30N135W. A tight
gradient associated to the trough was producing fresh to strong
SW winds over the northern Gulf waters as seen in the latest
scatterometer satellite data pass. Fresh to near gale-force
northerly gap winds are ongoing in the Gulf of Tehuantepec with
1008 mb low pressure, Invest EP91, located to the southeast
of the Gulf region along the monsoon trough near 12N94W. Seas
over this area 5 to 7 ft. Winds are moderate or lighter under
the broad high pressure as noted in the latest scatterometer
satellite data passes. Locally fresh northwest winds are near
Cabo Corrientes and Cabo San Lucas. Seas are 5 to 7 ft W of 110W
and offshore Baja California in northwest long-period swell,
except building to around 7 ft just ahead of the front, and 4 to
6 ft elsewhere E of 110W in primarily south to southwest swell.
In the Gulf of California, seas are 4 to 6 ft in the northern
portion, and 2 to 4 ft elsewhere.

For the forecast, moderate to fresh winds in the northern Gulf
of California will linger into Wed as a cold front approaches
with troughing ahead of it. Northerly swell will spread through
the waters west of Baja California tonight into Wed in the wake
of a weakening cold front that will move across Baja California
and the Gulf of California. Winds will freshen behind the front
offshore Baja California through Thu night as high pressure
builds in locally strong from near Cabo San Lazaro northward Wed
night into early Thu. Winds then will weaken there by the end of
the week into the weekend as the gradient slackens. Fresh to
strong northerly gap winds will persist in the Gulf of
Tehuantepec through early Thu afternoon.  Meanwhile, a broad
area of low pressure, Invest EP91, is near the coast of southern
Mexico. Environmental conditions appear conducive for gradual
development, and a tropical depression could form late this week
or over the weekend. This system is expected to move little
during the next few days, but a slow northwestward motion near
the coast of southern and southwestern Mexico is expected by the
weekend. Regardless of development, expect increasing winds and
building seas.

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

A broad 1008 mb low pressure, Invest EP91, located near the
coast of southern Mexico and portions of Central America, is
producing a large area of disorganized showers and thunderstorms
as described with the monsoon trough/ITCZ section above. Associated
winds are moderate to fresh offshore Guatemala and far western
El Salvador. Winds are moderate or lighter elsewhere. Seas are
4 to 6 ft in primarily southwest swell over these waters.

For the forecast, environmental conditions appear conducive for
gradual development, and a tropical depression could form late
this week or over the weekend. This system is expected to move
little during the next few days, but a slow northwestward motion
near the coast of southern and southwestern Mexico is expected by
the weekend. Regardless of development, expect increasing winds
and building seas, mainly west of the offshore waters of
Guatemala. Winds may freshen south of the monsoon trough as it
lifts northward through the remainder of the week, which would
build seas slightly.

...REMAINDER OF THE AREA...

A rather fast moving cold front extends from near 28N121W to
28N126W and northwestward to near 30N135W. Latest scatterometer
satellite data passes reveal gentle to moderate northwest to
north winds behind the front. A 0230Z Jason-3 altimeter
satellite data pass reveals seas of 8 to 11 ft in long-period
north swell behind the front. Otherwise, a broad ridge is across
the waters north of the monsoon trough and ITCZ ahead of the
front. The gradient between the ridge and relatively lower
pressures in the ITCZ/Monsoon Trough region is allowing for
gentle to moderate winds north 09N and west of about 116W.
Seas are mainly 4 to 7 ft away from the northerly swell in a
wide variety of mixed swell.

For the forecast, the cold front will move southeastward across
the waters N of 20N through Thu while weakening and eventually
dissipating. Winds will locally freshen behind the front as high
pressure builds in across the area. The seas of 8 to 11 ft in the
long-period north swell will continue to press southward through
Thu while decaying. Farther south, weak low pressure is likely
to form along the monsoon trough between 115W and 1202 through
Thu night. Looking ahead, a reinforcing set of long-period
northwest swell may arrive by the end of the week into the
weekend over the northwest and west-central portions of the area
maintaining seas to a rough state, with yet another set possibly
arriving early next week.

$$
Aguirre