Eastern Pacific Tropical Weather Discussion

371
AXPZ20 KNHC 181608
TWDEP 
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.
...SPECIAL FEATURES...
Gulf of Tehuantepec Gale Warning: N to NE gap winds continue to
gradually diminish across and downstream of the Gulf of
Tehuantepec this morning, the pressure gradient is relaxing in 
the wake of a departing tropical wave along 102W. Winds have
diminished below gale-force this morning, and the gale warning
has been allowed to expire. Seas across the area are estimated 
at 8 to 12 ft. Winds are forecast to diminish further throughout 
the day, and then continue to pulse to strong speeds at night for
the next few days. 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 83W from 03N northward and 
into the western Caribbean Sea, moving westward at around 20 kt. 
Scattered to numerous moderate and isolated strong convection is 
noted from 03.5N TO 14.5N BETWEEN 77W AND 86W
The axis of a tropical wave is near 102W from 03N to 16N, moving
westward at around 20 kt. Scattered moderate isolated strong 
convection is noted from 06N TO 15N BETWEEN 96.5W AND 106W. 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 130W from 17N southward to 
near the Equator, moving westward at around 15 kt. Scattered 
moderate to strong convection is noted from 06N to 13N between 
122W and 133W. 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 10.5N76W to 08N95W. The ITCZ 
extends from 10N98W to 06.5N114W to 10N128W, then resumes near
10N131W to beyond 09N140W. Other than the convection described 
above with three tropical waves, scattered moderate isolated 
strong convection is noted from 08.5N to 12.5N between 86W and
96W. Scattered moderate to strong convection is noted from 00N 
to 12N between 134W and 140W.
...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
The Gale Warning in effect overnight for the Gulf of Tehuantepec
has expired. Winds and seas across this area will slowly improve
throughout the day. 
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 to N winds continue near and offshore of 
Baja California from Punta Abreojos. Fresh to strong SE to S 
winds prevail across the northern Gulf of California, while winds
are variable across the remainder of the Gulf. Upper level low 
pressure along the south half of the Baja Peninsula continues to 
support strong thunderstorms shifting southward across Baja Sur 
and the adjacent waters to 21N. Seas are 4 to 6 ft across the 
Baja offshore waters, and 2 to 4 ft inside 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, 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 S winds will continue from the central Gulf of California
into northern portions through Wed. Thunderstorms are expected to
remain active across Baja Sur and the adjacent Gulf and Pacific
waters through Wed morning. Winds and seas are expected to build
across the outer offshore waters of southwestern Mexico by the 
end of the week into the upcoming weekend in association with a 
developing area of low pressure beyond the offshore waters.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, 
AND WITHIN 750 NM OF ECUADOR...
Fresh easterly gap winds are occurring across the Papagayo region
this morning and extend downwind to near 90W. Seas there are 6 to
7 ft. 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 south through 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 moving into the waters from Ecuador to the 
Galapagos Islands today will propagate into the remaining
regional waters through Thu, then quickly subside. 
...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 24N between
122W and 137W as seen by overnight scatterometer data, and is 
associated with the tropical wave at 130W. Fresh to locally 
strong winds and seas of around 8 ft are from 09N to 11N between 
98W and 103W, and are associated with the tropical wave at 102W.
Moderate to fresh winds and rough seas are also found south of 
04N between 90W and 140W. Rough seas to 9 ft 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.