213
AXPZ20 KNHC 151959
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Mon Dec 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
1900 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: The pressure gradient between
the high pressure over Mexico and the eastern north Pacific
monsoon trough is sustaining gale-force northerly winds across
the Gulf of Tehuantepec which are forecast to continue through
Tue morning. Winds may peak around 45 night overnight. By Tue
afternoon, the high pressure will begin to shift eastward and
weaken. Rough seas will are expected with the strongest winds,
peaking around 16 ft tonight. Please read the latest High Seas
issued by the National Hurricane Center at website:
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more
information.

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

The monsoon trough extends from 08.5N78W to 07N95W. The ITCZ
continues from that point to 08N111W to 07.5N125W. A surface
trough is analyzed from 15N128W to 06N126W. The ITCZ then
resumes W of the trough from 07N127.5W to beyond 06N140W.
Scattered moderate convection is noted from 05N to 10.5N between
77W and 86W, from 10N to 12N between 109W and 112W, from 07.5N to
10N between 116W and 120W, and from 09N to 12N between 124W and
127W.

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

A Gale Warning is in effect for the Gulf of Tehuantepec. Please
see the Special Feature section for more details.

A 1027 mb high center is analyzed just N of the area near
31N129W. Its associated ridge extends to near the Revillagigedo
Islands per ASCAT scatterometer data. The related pressure
gradient is allowing for gentle to moderate northwest to north
winds and slight to moderate seas over the Mexican offshore
waters N of 17N, except locally fresh in the central Gulf of
California per the ASCAT data due to a locally tight pressure
gradient between the ridging and troughing along the eastern
shore of the Gulf of California. Light and variable winds and
slight seas prevail elsewhere from 12N to 17N outside of the
Tehuantepec area.

For the forecast, gale-force winds over the Gulf of Tehuantepec
will prevail through Tue morning. Elsewhere, mainly gentle to
moderate winds and moderate seas will prevail through the middle
of the week. Fresh to strong northerly winds and rough seas will
develop mainly just beyond the offshore waters of Baja
California Norte by the middle part of the week. Moderate to
fresh winds will pulse near Cabo Corrientes during the middle of
the week. Fresh to at least strong gap winds and rough seas may
return in the Gulf of Tehuantepec by the end of the week into
next weekend.

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

Fresh to strong northeast winds prevail in the Gulf of Papagayo
region as high pressure builds in N of the Caribbean with lower
pressures along the monsoon trough over southern Costa Rica and
Panama. Light to gentle winds and moderate seas are elsewhere N
of 08N. S of 08N, gentle to moderate southerly winds and
moderate seas prevail, except slight seas nearshore Colombia and
eastern Panama. Active convection is present near Panama and
Costa Rica as described above with locally higher winds and seas
possible.

For the forecast, building high pressure N of the Caribbean and
lower pressures near the monsoon trough will continue to support
pulsing fresh to strong easterly trade winds and moderate seas
across the Gulf of Papagayo through midweek, possibly returning
Fri night into next weekend. Rough seas in the far offshore
waters of Guatemala will persist through Tue due to a Gulf of
Tehuantepec gale-force gap event. Moderate to fresh northerly
winds will pulse in the Gulf of Panama this week. Gentle to
moderate winds and slight to moderate seas will prevail
elsewhere.

...REMAINDER OF THE AREA...

A 1027 mb high center is analyzed just N of the area near 31N129W.
Its associated ridge extends to near the Revillagigedo Islands
per ASCAT scatterometer data. The pressure gradient between the
high and relatively lower pressures associated to a trough that
extends in the W-central waters as described above is bringing
moderate to fresh trade winds from 09N to 20N and W of 120W or
so, locally strong near the northern portion of the trough as
seen on recent ASCAT data. Rough seas prevail over these waters
in mixed long period swell along with shorter period wind
generated seas. Moderate southerly winds and moderate seas are
occurring S of the monsoon trough and ITCZ. Mainly gentle to
moderate winds and moderate seas prevail across the remainder of
the open waters.

For the forecast, the surface trough in the W-central waters will
move westward through the early part of the week while
weakening. High pressure will build further over the northern
waters into the middle portion of the week leading to a
tightening of the pressure gradient that will cause fresh to
strong easterly winds and rough seas over much of the tradewind
belt west of 120W. Over the eastern part of the area, fresh to
strong easterly winds and rough seas associated with the gale-
force gap wind event in the Gulf of Tehuantepec will spread
westward to near 106W from 08N to 12N through Tue. Seas will
build to rough near 30N140W this evening through Tue night in W-NW
swell. Meanwhile, a tight pressure gradient will develop
offshore southern California leading to fresh to locally strong
winds and rough seas in the N-central waters mid-week. Marine
conditions should improve overall during the upcoming weekend as
the pressure gradient slackens.

$$
Lewitsky