000
AXPZ20 KNHC 300914
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Tue Dec 30 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
0900 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Storm Warning: Minimal gale-force northerly 
winds are blowing across the Gulf of Tehuantepec and downwind to 
about 15N as a ridge builds across the eastern slopes of the 
Sierra Madre Mountains in Mexico, behind a cold front moving 
across the Gulf of America. Wind are forecast to increase to 
35 to 40 kt, with seas building to 9 to 12 ft by early this 
morning. Then, winds will further increase to minimal storm force
this afternoon and evening, with seas building to 12 to 18 ft. 
Large seas generated from this strong gap wind event will spread 
well away from the Tehuantepec area, with seas 8 ft or greater 
reaching as far west as 105W by this evening into tonight. Marine
interests transiting across or in the Gulf of Tehuantepec 
through tonight should be aware of this strong gap wind event, 
and take the necessary action to avoid this hazardous marine 
conditions over the affected waters. Gale conditions are forecast
to continue through Wed night. Conditions in the Tehuantepec 
region are forecast to begin to improve on Thu.

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. 

Complex Low Pressure System/Swell event: A 1006 mb surface low 
pressure is centered near 21N127W. A surface trough extends from 
the low center to 16N124W to 10N128W. An area of numerous 
moderate to isolated strong convection is noted E of the trough 
axis from 12N to 21N between 110W and 123W. This is associated 
with a broad upper-level cyclone over the same area. Recent 
satellite derived wind data indicate that winds related to this 
low have diminished below gale force, and the Gale Warning is 
allowed to expired. However, a large area of fresh to strong 
winds remains associated with this system, and continues to 
dominate roughly the waters N of 16N W of 118W. Seas of 8 to 12 
ft, primarily in NE swell, are noted from 14N to 27N W of 120W. 
As the low pressure moves northward over the next 24 to 48 hours 
winds and seas will gradually diminish. 

Please read the latest High Seas Forecast 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 10N85W to 06N92W. The ITCZ 
stretches from 06N92W to 07N105W, then continues from 10N128W to
beyond 06N140W. Most of the convective activity is associated 
with the above mentioned low pressure centered near 21N127W. 

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

A Storm Warning is in effect for the Gulf of Tehuantepec. Please
refer to the Special Features section for more details. 

A 1027 mb high pressure is located well north of the area near 
42N129W. A ridge axis extends from the high across the offshore 
forecast waters of Baja California supporting gentle to moderate
north to northeast winds with moderate seas, with the exception 
of moderate to locally fresh NE winds in the Bay of Sebastian 
Vizcaino. Fresh to strong NW to N winds are evident across the
Gulf of California due to the presence of a strong 1044 mb high 
pressure over the Great Basin. Seas are likely 6 to 8 ft within
these wind speeds. Scatterometer data also show fresh to strong 
N winds in the vicinity of San Jose del Cabo. Elsewhere, gentle 
to moderate winds and moderate seas in NW swell are noted. 

For the forecast, a gap wind event is ongoing in the Gulf of
Tehuantepec. See the Special Features section for more details. 
Fresh to strong northwest winds and moderate to rough seas will 
prevail across most of the Gulf of California through tonight as 
high pressure persists over the SW of the United States. 
Elsewhere, moderate or weaker winds and slight to moderate seas 
are expected.

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

Strong high pressure building north of the region is supporting 
fresh to strong northeast to east winds in the Gulf of Papagayo 
and downwind to near 88W. Seas of 5 to 7 ft are within these 
winds. Elsewhere, moderate or weaker winds and slight to moderate
seas prevail.

For the forecast, the aforementioned high pressure will continue
to support fresh to strong NE to E winds in the Gulf of Papagayo
with moderate to rough seas through the forecast period. The
forecast calls for winds of 20 to 30 kt, mainly at night, with 
seas building up to 10 ft through Thu night. Gentle to locally 
moderate northerly winds are expected in the Gulf of Panama 
through Fri. Seas generated by strong winds in the Tehuantepec 
region will propagate across the offshore forecast waters of 
Guatemala and El Salvador today through Wed night. Light to 
gentle winds and slight to moderate seas are expected elsewhere 
through this work-week.

...REMAINDER OF THE AREA...

Please read the Special Features section for details on a complex
low pressure system, and a significant swell event over the central
waters of the forecast region. Gentle to moderate winds and 5 to
7 ft seas primarily in NW swell are evident elsewhere.

For the forecast, outside of the complex low pressure system and
the swell event, a cold front is forecast to reach near 30N140W 
Wed night and move westward across the waters north of 25N into 
Thu. A reinforcing front will also reach the same area later on 
Thu, merging with the main front by Thu evening. At that time,
the front will extend from 30N134W to 24N140W. Fresh to strong 
winds are expected on either side of the front. A new swell event
will follow the front bringing rough to very roughly seas.

$$
GR