181
AXPZ20 KNHC 161546
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Thu Oct 16 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 1200 UTC surface analysis and satellite imagery through
1530 UTC.

...SPECIAL FEATURES...

South of Southern Mexico (Invest EP91): A broad area of low
pressure is producing some disorganized showers and thunderstorms
offshore of southern Mexico, generally from 11N to 15N between
94W and 101W. Environmental conditions appear conducive for
gradual development of this disturbance, and a tropical
depression could form during the next few days. The system is
forecast to move slowly west-northwestward or northwestward near
the coast of southern and southwestern Mexico through the
weekend. There is a medium chance of tropical development within
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 08N78W to 08N82W to EP91
centered near 12N98W to 08N130W. The ITCZ continues from 08N130W
to beyond 09N140W. Scattered moderate convection is occurring
from 04N to 13N between 81W and 96W, and from 08N to 10N between
115W and 117W.

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

Please read the Special Features section for information on EP91
and the potential tropical development off the coast of southern
Mexico.

Fresh to strong N to NE gap winds are occurring in the Gulf of
Tehuantepec as a 1013 mb high prevails over east-central Mexico.
Elsewhere, ridging extends over the Baja California waters,
stemming from a 1030 mb high centered northwest of the area near
37N144W. The pressure gradient between this ridge and a surface
trough extending from northwestern Mexico to 18N106W is
supporting moderate to locally fresh NW winds and 5 to 8 ft seas
over the Baja waters. In the Gulf of California, moderate to
occasionally fresh NW winds and 1 to 3 ft seas prevail. Mainly
moderate NW winds and 5 to 6 ft seas are noted offshore of
southwestern Mexico.

For the forecast, fresh to strong N to NE winds in the Gulf of
Tehuantepec will diminish by this afternoon. Elsewhere, moderate
to occasionally fresh NW winds and locally rough seas will
prevail offshore of Baja California through Fri morning. Pulsing
moderate to fresh NW winds will also be possible in the Gulf of
California through this evening. Looking ahead, a broad area of
low pressure, EP91, is centered offshore of southern Mexico.
Environmental conditions appear conducive for gradual development
of this disturbance, and a tropical depression could form during
the next few days. The system is forecast to move slowly west-
northwestward or northwestward near the coast of southern and
southwestern Mexico through the weekend. There is a medium chance
of tropical development within the next 48 hours. Regardless of
development, increasing winds and building seas are expected
offshore of southern Mexico through this weekend.

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

Moderate to locally fresh SW winds and 5 to 6 ft seas are
occurring well offshore of Guatemala as EP91 churns offshore of
southern Mexico. Mainly moderate S to SW winds and 4 to 6 ft seas
are noted elsewhere south of the monsoon trough. To the north,
light to gentle winds and 3 to 4 ft seas prevail.

For the forecast, fresh to occasionally strong SW winds and
locally rough seas will occur in association with EP91 well
offshore of Guatemala through Fri night. Otherwise, moderate SW
winds and moderate seas are expected south of the monsoon trough
into early next week, with gentle winds and moderate seas
prevailing to the north.

...REMAINDER OF THE AREA...

A 1030 mb high centered northwest of the area near 37N144W
extends ridging over the eastern Pacific waters north of the
monsoon trough and ITCZ. Moderate to fresh N to NE winds are
occurring in this region, and rough seas of 8 to 9 ft in N swell
are noted north of 15N. Elsewhere, moderate to fresh SW winds are
occurring north of 03N and east of 110W in association with
EP91. Mainly moderate S to SE winds and 5 to 7 ft seas are
occurring elsewhere south of the monsoon trough and ITCZ.

For the forecast, moderate to occasionally fresh N to NE winds
and rough seas will occur north of the monsoon trough and ITCZ
into this weekend as high pressure prevails to the north. Winds
will diminish slightly for the remainder of the weekend. A new NW
swell will support rough seas north of 25N Fri night through Sun
morning. Elsewhere, fresh to occasionally strong SW winds and
locally rough seas will occur in association with EP91 north of
05N and east of 105W into early Sat. Looking ahead, increasing
winds and building seas are expected over the northern waters
early next week as a weakening cold front moves southward along
the California coast.

$$
ADAMS