658
AXPZ20 KNHC 180757
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Tue Aug 18 2026

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
0730 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: A very tight local pressure
gradient is present over the Gulf of Tehuantepec area in the
wake of a departing tropical wave with a tight ridge of high
pressure nosing down eastern to southeastern Mexico, as well as a
surface trough to the northeast over the western Yucatan
Peninsula. This pressure is likely supporting minimal gale-force
northerly gap winds in the Gulf of Tehuantepec, with seas of 7
to 11 ft. Winds are forecast to diminish below gale-force to
later this morning. Please, refer to the latest NWS High Seas
Forecast available at website:
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details.

...TROPICAL WAVES...

The axis of a tropical wave is near 80W from 03N offshore of the
border of Ecuador and Colombia northward to across the Gulf of
Panama and Panama and into the western Caribbean Sea, moving
westward at around 20 kt. Scattered to numerous moderate and
isolated strong convection is noted from 01N to 11N between 77W
and 91W.

The axis of a tropical wave is near 100W from just south and
offshore Guerrero, Mexico southward to near the Equator, moving
slowly westward at around 20 kt. Scattered moderate isolated
strong convection is noted from 05N to 10N between 95W and 100W.
An area of low pressure is forecast to form several hundred
nautical miles south of the coast of southern Mexico around the
end of the week. Gradual development of this system is likely
thereafter, and a tropical depression is expected to form this
weekend while the system moves west-northwestward, remaining well
offshore of Mexico.

The axis of a tropical wave is near 127W from 17N southward to
near the Equator, moving westward at around 10 kt. Scattered
moderate isolated strong convection is noted from 06N to 14N
between 112W and 140W. Environmental conditions appear conducive
for gradual development of this system, and a tropical depression
could form towards the end of the week or over the weekend while the
system moves generally westward across the western portion of the
east Pacific and into the central Pacific.

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

The monsoon trough extends from the SW Caribbean Sea to across
Costa Rica, entering the Pacific at the coast near 09.5N84W to
07N110W. The ITCZ extends from 07N110W to 08.5N125W, then
resumes west of a tropical wave from 09N131W to beyond 09N140W.
Other than the convection described above with three tropical
waves, scattered moderate isolated strong is noted from 00N to
06N between 131W and 140W.

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

Please refer to the Special Features section above for details
on a Gale Warning in effect in the Gulf of Tehuantepec until
around sunrise this morning.

Please refer to the Tropical Waves section above for information
on a tropical wave that has a potential for tropical development
offshore Mexico this upcoming weekend.

Moderate to fresh NW-N winds are found offshore Baja California
from Punta Eugenia northward, locally strong near San Fernando to
Punta San Carlos per recent ASCAT data. Fresh to strong E to SE
winds are surging up the along the southern to central Gulf of
California where a strong thunderstorm complex is present.
Scattered to numerous thunderstorms are noted from 21N to 28N
between mainland Mexico and Baja California Sur. Seas are 4 to
6 ft across the remainder of the offshore waters, except 1 to 3
ft in the Gulf of California.

For the forecast, the pressure gradient between high pressure
over the Gulf of America and relatively lower pressure south of
Mexico will continue to induce pulses of strong north winds over
the Gulf of Tehuantepec through Wed night, to minimal gale-force
through this early morning, with moderate to fresh pulses then
starting Thu. Seas will occasionally build to rough with the
fresh to strong or stronger winds. A surge of strong SE winds
will move from the southern to central Gulf of California
into early today, associated with a complex of convection. Fresh
to strong SE winds may pulse in the northern Gulf of California
tonight. Winds and seas may build across the outer offshore
waters of southwestern Mexico by the end of the week into the
upcoming weekend in association with a possibly developing area
of low pressure beyond the offshore waters.

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

See Tropical Waves section above for information on a tropical
wave producing heavy rainfall over portions of Colombia, Panama
and areas northwestward, with heavy thunderstorms also over the
adjacent offshore waters as described above.

Fresh to strong winds are in the Gulf of Papagayo per recent
ASCAT scatterometer data. Winds are moderate or weaker elsewhere,
except moderate to fresh south of the monsoon trough near the
Galapagos Islands. Seas are 4 to 7 ft in long-period S to SW
swell, except 7 to 9 ft southwest of the Galapagos Islands.

For the forecast, the pressure gradient between high pressure
over the western Caribbean and relatively lower pressure over
Central America will lead to pulsing strong to near gale-froce
northeast to east gap winds over the Papagayo region through Thu,
with resultant rough seas, then moderate to fresh winds
thereafter. Moderate to fresh associated winds will extend well
downwind across the outer offshore waters of El Salvador and
Guatemala at times. Moderate to fresh southerly winds south of
the monsoon trough will diminish later this morning. Large
southerly swell will impact waters mainly from Ecuador to the
Galapagos Islands through Thu, largest expected through tonight.

...REMAINDER OF THE AREA...

See Tropical Waves section above for information on two tropical
waves that have potential for tropical development later this
week and into the upcoming weekend.

Moderate to fresh E winds are noted from near 10N to 19N between
124W and 138W as seen by recent ASCAT scatterometer data, and
is associated with the tropical wave at 127W. Fresh to locally
strong winds and seas of around 8 ft are from 09N to 11N between
98W and 103W as seen by ASCAT, and are associated with the
tropical wave at 100W. Moderate to fresh winds and rough seas
are also found south of 04N between 90W and 140W. Rough seas are
south of 04N between 88W and 128W in SE to S swell, except in
the lee of the Galapagos Islands. Winds are moderate or weaker
across the remainder of the open waters, with seas of 4 to 7 ft.

For the forecast, regardless of tropical development, the
tropical waves described in the above section will bring some
increasing winds and seas to area waters. Away from these waves,
little change is expected in marine weather through the week,
with conditions a bit more tranquil across the open waters by the
upcoming weekend.

$$
Lewitsky