281
AXPZ20 KNHC 150952
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 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 0600 UTC surface analysis and satellite imagery through
0945 UTC.

...SPECIAL FEATURES...

South of Southern Mexico (Invest EP91):
Low pressure of 1007 mb is analyzed along the monsoon trough near
12N94W. Scattered moderate to isolated strong convection is
within 60 nm SE of the low. This feature is part of a broad area
of low pressure that is producing disorganized scattered moderate
convection near the coast of southern Mexico and portions of
Central America. 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. This system has a medium chance of becoming a
tropical cyclone during the next 48 hours. Please refer to the
latest NHC Tropical Weather Outlook at www.hurricanes.gov for
more details.

...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 central Costa Rica, and continues northwestward to 11N86W
to low pressure, Invest EP91, near 12N94W 1007 mb to 10N103W
to 11N113W and 08N121W, where it transitions to the ITCZ to
07N128W to 11N135W and to beyond 11N140W. Scattered moderate
to isolated strong convection is seen from 06N to 09N between
94W-101W.

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

Please read the Special Features section above for information on a
broad area of low pressure, Invest EP91, that is near the coast of
southern Mexico with potential for tropical cyclone formation.

A trough extends from SW Arizona southwestward to across the
northern Gulf of California and to across southern Baja
California as broad high pressure ridging remains west of
Baja California. A cold front is analyzed from near 30N117W to
28N126W and to near 30N135W. Fresh to near gale-force northerly
gap winds are ongoing in the Gulf of Tehuantepec with 1007 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 as seen in an overnight scatterometer
satellite data pass. Seas are 5 to 7 ft W of 110W and offshore
Baja California in northwest long-period swell, except for
higher seas of 7 to 10 ft north of Punta Eugenia. Seas are about
4 to 6 ft E of 110W in primarily south to southwest swell. In the
Gulf of California, seas are 3 to 4 ft, except for slightly
higher seas of 4 to 5 ft in southwest long- period swell at the
entrance to the Gulf.

For the forecast, northwest swell moving through the waters west
of Baja California will gradually subside through Thu morning.
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...

Please read the Special Features section above for information on a
broad area of low pressure, Invest EP91, that is near portions of
the coast of Central America, with potential for tropical cyclone
formation.

A 1007 mb low along the monsoon near 12N94W is part of the the
Special Features broad area of low pressure. Moderate to fresh
east to southeast winds along with seas of 5 to 6 ft are north
and north of the low while moderate southeast winds are northeast
of the low to the waters near the northwest part of El Salvador
and extreme southern Guatemala. Seas are 4 to 6 ft primarily in
southwest swell over these waters.

For the forecast, in association with the Special Features
broad area of low pressure, 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 could lead to slight build up
of seas.

...REMAINDER OF THE AREA...

A rather fast moving cold front extends from near 30N117W to
26N126W and northwestward to near 30N135W. Overnight 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 north of about 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 as depicted in the global models.
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