154
AXPZ20 KNHC 152014
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 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 1800 UTC surface analysis and satellite imagery through
2000 UTC.

...SPECIAL FEATURES...

South of Southern Mexico (Invest EP91): A broad 1007 mb area of
low pressure near 12.5N95.5W is producing some disorganized
showers and thunderstorms offshore of southern Mexico and
portions of Central America as described with the monsoon trough
below. Currently winds are up to around 20 kt with stronger
winds just NW associated with a Gulf of Tehuantepec gap wind
event where seas are 7-9 ft. Environmental conditions appear
conducive for gradual development of this disturbance, and a
tropical depression could form late this week or over the
weekend. The system is forecast to move little during the next
couple of days, but a slow west- northwestward or northwestward
motion near the coast of southern and southwestern Mexico is
expected by the weekend. This system has a medium chance of
tropical cyclone formation within 48 hours and 7 days. 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 near
11N75W to 11N86W to 12N92W to 10N102W to 11.5N114.5W to 07N123W
to 08.5N131.5W. The ITCZ extends from 08.5N131.5W to beyond
10n140w. Widely scattered moderate convection is noted from 03N
to 11N between 77W and 91.5W, from 08.5N to 13.5N between 91.5W
and 104W, and from 13N to 16N between 92W and 97W. Similar
convection is noted within 180 nm of the coast of Mexico between
101W and 105.5W.

...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 the potential for tropical cyclone
formation.

A weakening cold front extends from SW Arizona to across Baja
California Norte through 30N114.5W to 24N126W to 26N124W. Broad
high pressure is building in the wake of the front. NW-N moderate
winds are found even out ahead of the front as the high bridges
across, with these winds W of 108W or so. Associated NW swells
are arriving offshore Baja California Norte with seas of 7-10 ft
there. Seas are 5-7 ft elsewhere W of 108W. Strong to near gale-
force N-NE winds are in and downwind of the Gulf of Tehuantepec
with seas of 6-9 ft. Mainly light to gentle winds and 4-6 ft are
elsewhere, with seas of 1-3 ft in the Gulf of California N of the
entrance.

For the forecast, NW swell moving through the waters W of Baja
California will gradually subside through Thu morning. Fresh to
strong, locally near gale-force this evening, northerly gap
winds will persist in the Gulf of Tehuantepec through early Thu
afternoon. Meanwhile, a broad area of low pressure, Invest EP91,
is offshore southern Mexico. Environmental conditions appear
conducive for gradual development of this disturbance, and a
tropical depression could form late this week or over the
weekend. The system is forecast to move little during the next
couple of days, but a slow west-northwestward or northwestward
motion near the coast of southern and southwestern Mexico is
expected by the weekend. Regardless of development, expect the
potential for 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 offshore
southern Mexico just W of the offshore waters of Guatemala, with
the potential for tropical cyclone formation.

Otherwise, gentle to moderate winds prevail across the offshore
waters, locally fresh S of 06N. Seas are 4-6 ft in mixed swells.
Active convection is noted across the waters as described above
with locally higher winds and seas possible.

For the forecast, in association with the Special Features
broad area of low pressure, expect increasing winds and building
seas, mainly W of the offshore waters of Guatemala. Winds may
freshen S of the monsoon trough as it lifts northward through
the remainder of the week, which could lead to a slight build up
of seas. Expect tranquil marine conditions across the waters late
in the weekend into early next week.

...REMAINDER OF THE AREA...

A weakening cold front extends from SW Arizona to across Baja
California Norte through 30N114.5W to 24N126W to 26N124W. Broad
high pressure is building in the wake of the front. Moderate are
found behind the front, with gentle to moderate winds elsewhere
N of the monsoon trough and ITCZ. Winds are moderate S of the
monsoon trough and ITCZ, except to fresh E of 105W to the S of
the axis and N of 04N. For seas, northerly swell of 7-10 ft
associated with the front are found N of 23N, with 5-7 ft seas
in mixed swells S of 23N. Weak troughing has developed just N of
the monsoon trough near 117W to 17N.

For the forecast, the dissipating cold front will gradually
decay to a remnant frontal trough by early Thu, then dissipate by
the end of the week. Winds will locally freshen behind the front
as high pressure builds in across the area. Rough northerly
swell in the northern waters will continue to press southward
through Thu while decaying. Farther S, weak low pressure is
likely to form along the trough just N of the monsoon trough
between 115W and 120W 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 NW and W-central portions of the area
maintaining seas to a rough state, with yet another set possibly
arriving early next week.

$$
Lewitsky