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Eastern North Pacific Tropical Weather Discussion


000
AXPZ20 KNHC 092026
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Tue Dec 9 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...

Gulf of Tehuantepec Gale Warning: The pressure gradient between 
high pressure over the eastern slopes of Mexico and lower 
pressure within the eastern north Pacific monsoon trough is 
supporting gale- force gap winds in the Gulf of Tehuantepec. The
area of high pressure will weaken tonight, which will loosen the
pressure gradient and diminish winds below gale force. Very 
rough seas, peaking around 12 or 13 ft, will start to subside 
tonight as the winds diminish. 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. 

Of note: The monthly distribution of Tehuantepec events shows 
that the largest number of gale force events occurs in December. 
Storm- force events occur most often in January. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

The monsoon trough extends from 09N84W to 06N101W to 12N116W to 
08N130W. The ITCZ continues from 08N130W to 07N140W. Scattered 
moderate and isolated strong convection is noted from 09N to 18N
between 109W and 119W, and from 08N to 14N between 119W and 125W.
Scattered moderate convection is noted from 06N to 09N between 
130W and 140W.

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

A Gale Warning is in effect for the Gulf of Tehunatepec. Please 
see the Special Features section for more information. 

Aside from conditions in the Gulf of Tehuantepec, a ridge 
extends from high pressure located N of the area to across the 
offshore forecast waters of Baja California. The pressure 
gradient between this ridge and a trough over western Mexico is 
supporting moderate to fresh winds over the Gulf of California. 
Gentle to moderate winds are over the waters near the 
Revillagigedo Islands. Light to gentle winds and moderate seas in
long period NW swell are noted across the remainder of the 
Mexican offshore waters.

For the forecast, gale-force northerly gap winds in the Gulf of
Tehuantepec will diminish tonight, with fresh to strong winds
continuing though the end of the week. Winds over Tehuantepec 
will diminish on Saturday before strengthening again on Sunday. 
Fresh N winds may develop near Cabo Corrientes tonight through 
Wed night.

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

Moderate to fresh winds are in the Gulf of Papagayo, with light 
to gentle winds elsewhere N of 05N. Gentle to locally moderate 
southerly winds prevail S of 05N. Seas are mainly moderate in 
mixed SW and NW swell, with exception of slight seas nearshore 
from Colombia northward.

For the forecast, mainly gentle winds will prevail N of the 
monsoon trough over the next several days, except pulsing to 
moderate to fresh in the Gulf of Papagayo, locally strong at 
times. Gentle to moderate winds will prevail S of monsoon trough.
Moderate N winds will pulse in the Gulf of Panama starting 
tonight. Seas across the outer offshore waters of El Salvador and
Guatemala, generated by a gale-force gap wind event in the Gulf 
of Tehuantepec, will subside tonight. Otherwise, moderate seas in
mixed SW and NW swell are expected over the regional waters 
through the week and into next weekend.

...REMAINDER OF THE AREA...

High pressure dominates the waters N of the ITCZ and monsoon
trough. The pressure gradient between this area of high pressure
and lower pressure in the vicinity of the ITCZ and within the 
monsoon trough is supporting moderate to fresh winds north of the
monsoon trough/ITCZ and west of 110W. Seas are in the 5-8 ft 
range over these waters, highest S of 20N and W of 120W. Moderate
winds, and seas of 4 to 7 ft, prevail elsewhere over the 
discussion waters.

For the forecast, little change to the synoptic pattern and
marine conditions are expected through the middle of the week,
with winds weakening somewhat later in the week as the pressure
gradient weakens. A new set of long period NW swell is forecast 
to reach the NW part of the forecast region by Wed evening, 
building seas to 8 to 9 ft over these waters before subsiding by 
the end of the week.
 
$$
AL