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Eastern North Pacific Tropical Weather Discussion


000
AXPZ20 KNHC 150840
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Sat Aug 15 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...

Tropical Depression Hernan is centered near 16.4N 133.8W at
15/0900 UTC, moving west at 11 kt. Estimated minimum central
pressure is 1006 mb. Maximum sustained wind speed is 30 kt with
gusts to 40 kt. Peak seas are around 10 ft or 3.0 m. Hernan is once 
again strongly sheered with scattered moderate isolated strong 
convection between 240 nm and 480 nm in the NE quadrant only. The 
depression is moving toward the west and this general motion is 
expected to continue through the next few days. Sow weakening is 
forecast during the few days, and Hernan is forecast to degenerate 
to a remnant low pressure area of Sat. Please read the latest HIGH 
SEAS FORECAST issued by the National Hurricane Center at website - 
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Hernan 
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for 
more details.

...TROPICAL WAVES...

The axis of a tropical wave is near 83.5W north of 06N to across
portions of Costa Rica and continuing in the western Caribbean 
Sea along the Caribbean coast of Nicaragua, moving west around 
15 kt. Nearby convection is discussed in the ITCZ/monsoon trough
section below.

The axis of a tropical wave is near 102W north of the Equator to
near southwestern Mexico near the coast of Guerrero, moving west
around 15 kt. Nearby convection is discussed in the ITCZ/monsoon
trough section below.

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

The monsoon trough extends from 1007 mb low pressure over
northern Colombia at 10N75W to along the southern coast of Panama
at 07N80W to 10N91W to 06.5N104W. The ITCZ begins there and 
extends to southeast of Tropical Depression Hernan at 13N127W. 
Numerous moderate scattered strong convection is noted from 05N
to 09N between 77W and 85W. Isolated to widely scattered 
moderate and isolated strong convection is noted within 390 nm
south of the monsoon trough between 85W and 98W, and within 300
nm either side of the ITCZ between 98W and 127W.

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

Fresh to locally strong N gap winds are occurring over the Gulf
of Tehuantepec as measured by recent ASCAT scatterometer passes.
Moderate to locally fresh NW winds are near the Pacific coast of
Baja California, with moderate to fresh SW winds in the northern
Gulf of California north of 30N. Elsewhere, winds are moderate 
or weaker. Seas are 5-7 ft over the Gulf of Tehuantepec, 4-6 ft 
over the remaining Pacific waters, and 1-3 ft over the Gulf of 
California. No significant deep convection is occurring over the 
Mexican offshore zones.

For the forecast, high pressure over the Gulf of America will
continue to force pulses of fresh to strong N winds with locally
near- gale speeds over the Gulf of Tehuantepec for the next 
several days. Additionally, moderate to fresh NW winds are 
forecast off of the Baja California peninsula through Mon night, 
locally strong at times. Moderate to fresh SE winds may move up 
the central to the northern Gulf of California Mon night and Tue.
Elsewhere, winds and seas should remain quiescent until at least
mid next week. Looking ahead, an area of low pressure could form
several hundred nautical miles south of the coast of southern 
Mexico by the early to middle part of next week. Some gradual 
development of this system is possible thereafter while the 
system moves westward or west-northwestward well south of 
Mexico. 

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

Fresh to strong NE to E gap winds are observed by recent OSCAT-3
scatterometer data over the Gulf of Papagayo region with seas 
5-8 ft. Elsewhere, winds are moderate or weaker across forecast 
waters, except locally fresh near the entrance to the Gulf of 
Guayaquil. Seas are 4-7 ft in SW swell over the remainder of 
forecast waters. Scattered to numerous convection is present as 
described with the monsoon trough above over the waters off
Panama and southern Costa Rica.

For the forecast, high pressure over the W Caribbean will 
contribute toward fresh to strong E gap winds over the Gulf of 
Papagayo region through Sun night before weakening early next 
week with winds diminishing to moderate to fresh there. Moderate 
to fresh southerly winds will pulse south of the monsoon trough 
through Mon. Large southerly swell will impact the waters mainly 
from Ecuador to the Galapagos Islands through the next several 
days, largest by midweek.
 
...REMAINDER OF THE AREA...

Please see Special Features section above for more on Tropical 
Depression Hernan. 

Surface ridging extends from 30N128W to 181N113W. Aside from 
conditions associated with Hernan, moderate to fresh winds are 
across the remainder of the waters from 15N to 26N to the west 
of 124W. Seas are 7-10 ft across those waters. Winds are 
moderate or weaker across the remainder of the waters north of 
the Equator with seas of 5-7 ft, locally 8 ft near the Equator
between 100W and 116W. Moderate to fresh SE winds and 7-9 ft 
seas are found south of the Equator. Any convection is described 
above in the monsoon trough/ITCZ section.

For the forecast, Tropical Depression Hernan will become a remnant
low and move to 16.5N 135.5W this afternoon, 16.6N 137.8W Sun 
morning, 16.7N 139.9W Sun afternoon, moving west of the area to
near 16.8N 141.9W Mon morning, 16.8N 143.9W Mon afternoon, and 
dissipate Tue morning. Moderate to fresh SE winds will prevail 
south of the Equator. Rough seas will pulse on either side near 
the Equator to the east of 130W through the next several days in 
persistent and reinforced southerly swells.

Looking ahead, an area of low pressure could form well to the 
west-southwest of the southern tip of the Baja California 
Peninsula by the early to middle part of next week. Gradual 
development of this system is possible thereafter while it moves 
generally westward across the western portion of the east 
Pacific. Additionally, an area of low pressure could form several
hundred nautical miles south of the coast of southern Mexico by 
the early to middle part of next week. Some gradual development 
of this system is possible thereafter while the system moves 
westward or west-northwestward well south of Mexico.

$$
Lewitsky