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Eastern North Pacific Tropical Weather Discussion


000
AXPZ20 KNHC 280409 CCA
TWDEP 

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
0405 UTC Sun Dec 28 2025

Corrected Special Features section

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 0000 UTC surface analysis and satellite imagery through
0345 UTC.

...SPECIAL FEATURES...Corrected

Significant Swell and Developing Low Pressure: Large northwest 
swell continues to induce rough to very rough seas over the 
waters north of about 18N and west of about 116W, with seas 
peaking to around 13 ft (4.m) from 21N to 26N between 120W and 
123W. Wave period with these seas is of 12-14 sec. Rough seas 
extend southward to near 10N and east-northeast to the offshore 
waters of Baja California, including Sebastian Vizcaino Bay. The
swell will slowly subside through late Sun south of 28N. Rough 
seas of 8 to 12 ft are likely to prevail into Mon over the waters
just west of the Baja California Sur offshore zones, roughly 
from 15N to 25N.

In addition, a surface trough analyzed from near 20N124W to
15N126W and to 12N127W in conjunction with a vigorous and broad 
upper trough is producing a large area of moderate to heavy rain 
with embedded scattered to numerous showers and thunderstorms 
generally from 14N to 23N between 120W and 125W. Scattered 
moderate convection is from 10N to 14N between 116W and 121W. An 
earlier scatterometer satellite data pass indicated that strong 
to near gale-force winds are occurring with the strongest 
convection. Global models suggest that a low pressure will 
develop in association with this trough across the waters south 
of about 22N between 120W and 128W Sun into early next week. This
will combine with high pressure building into the region is 
expected to result in a rather broad zone of increasing winds 
reaching to strong speeds roughly from 16N to 26N and west of the
Revillagigedo Islands, accompanied by scattered showers and 
isolated thunderstorms. There is a possibility of these winds 
reaching gale-force speeds, especially in squalls. Rough to very 
rough seas will spread over much of the basin north of 10N and 
west of 115W. Seas may reach up to 15 ft with the strongest 
winds. Conditions are forecast to improve by the middle of the 
upcoming week.

Gulf of Tehuantepec Gale Warning: Strong high pressure over 
the southern United States and across eastern Mexico in the 
wake of an upcoming Gulf of America cold front will result
in a tight pressure gradient that is expected induce gale-force 
winds north winds into the Gulf of Tehuantepec region beginning Mon 
night. These winds may peak to, or near 45 kt going into the middle 
part of the upcoming week. Seas with these winds are expected to 
rapidly build to the range of 10 to 16 ft (3 to 5 m) with these 
winds.

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 axis extends from northern Colombia to 08N79W 
to 08N91W to 07N99W, where latest scatterometer satellite data
indicates that it transitions to the ITCZ to 08N110W to 10N125W 
to 08N134W and to beyond the area at 08N140W. Scattered moderate
convection is seen from 10N to 14N and between 116W and 121W.

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

Please refer to the Special Features section for details on 
a gale warning that is in effect for the Gulf of Tehuantepec.

A 1032 mb high pressure system centered well north of the 
area near 41N133W has an associated ridge that extends 
southward to near 20N and west of the Revillagigedo Islands. 
Its related gradient is allowing for fresh north to northeast 
winds to exist across the offshore waters of Baja California. A 
decaying northwest swell is providing for seas of 8 to 12 ft 
north of Punta Eugenia and 6 to 9 ft in northwest swell south of
Punta Eugenia. Moderate to locally fresh northwest winds and 
slight to moderate seas are found in the Gulf of California. 
Meanwhile, winds in the Gulf of Tehuantepec have diminish below 
strong force and currently, moderate to fresh northerly winds 
prevail. Seas over these waters are 4 to 6 ft. Elsewhere, 
moderate or weaker winds and slight to moderate seas prevail.

For the forecast, northwest swell propagating through the 
offshore waters of the Baja California peninsula will slowly 
subside through early Mon. Fresh to locally strong northwest 
winds are likely to develop in the Gulf of California Sun into 
Tue as high pressure strengthens across the region. Weak high 
pressure will support moderate to fresh N winds in the Gulf of 
Tehuantepec through Sun morning. Looking ahead, a strong cold 
front will move across the Gulf of America Mon into Tue. High 
pressure building in behind the front will support the next gap 
wind event in the Gulf of Tehuantepec, reaching gale conditions 
late Mon night and continuing through Wed night. Winds may peak 
around 40 or 45 kt leading rough to very rough seas. Conditions 
will improve Thu into Fri. 

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

A broad high pressure centered over the eastern Gulf of America
extends southward into the region. An earlier scatterometer 
satellite data pass captured fresh to strong northeast to east
winds in the Gulf of Papagayo region. Seas over these waters are
4 to 6 ft. Weak low pressure off Colombia is producing isolated
showers and thunderstorms. Elsewhere, moderate or weaker winds 
and moderate seas prevail.

For the forecast, high pressure north of the basin will support
pulsing fresh to strong easterly trade winds in the Gulf of
Papagayo through the forecast period. Gentle to moderate
northerly winds are expected in the Gulf of Panama through the
period, pulsing to fresh at night at times. Gentle or lighter 
winds and slight to moderate seas are expected elsewhere through 
the period. 

...REMAINDER OF THE AREA...

Please read the Special Features section for details on significant
swell over the waters west of Baja California, and for conditions
that will soon be associated with low pressure impacting most of
the northern waters and a section of the central waters.

Broad ridging associated to strong high pressure that is
centered well north of the area extends southward into the area
near 20N. The gradient between the ridge and relatively lower
pressure in the tropics is allowing for moderate to fresh
trade winds north of about 10N and west of 120W. Seas are 
15W. Seas outside the Special Feature significant swell area
are 8 to 13 ft. Elsewhere, moderate or weaker winds and moderate
seas are prevalent.

For the forecast, the decaying northwest swell is forecast to
slowly subside through early Mon as high pressure builds into 
the regional waters. The surface trough in the trades waters near
122W will support the formation of a broad low pressure on Sun. 
The tight pressure gradient between the subtropical ridge and the
low pressure will sustain a large area of strong to near gale- 
force winds and rough to very rough seas, occupying much of the 
forecast waters north of 10N and west of 115W into early next 
week. Winds may reach gales at times, especially in squalls. 
Conditions will improve midweek. Looking ahead, a cold front will
move across the NW waters late next week and strong NW winds and
rough to very rough seas may follow the front.

$$
Aguirre