Eastern Pacific Tropical Weather Discussion

271
AXPZ20 KNHC 202137
TWDEP 
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Thu Aug 20 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 1800 UTC surface analysis and satellite imagery through
2030 UTC.
...TROPICAL WAVES...
The axis of a tropical wave is moving over eastern portions of 
the Tropical Pacific basin along 84W, north of 04N, moving 
westward at 15 to 20 kt. Scattered to numerous moderate to strong
convection is noted from 03.5N to 11.5N E of 87W.
The axis of a tropical wave is near 99W, from 05N to 18N, moving
westward at 10 to 15 kt. Scattered to numerous moderate to 
strong convection stretches from 06.5N to 16.5N between 92W and 
107W, as the wave interacts with a middle level trough extending
off the SW coast of Mexico. Environmental conditions appear 
favorable for gradual development, and a tropical depression is 
likely to form this weekend or early next week while the system 
moves west-northwestward or northwestward, remaining well 
offshore of Mexico.
The axis of a tropical wave is near 113W from 05N to 17N, moving
westward at 10 to 15 kt. An area of low pressure associated with
this tropical wave near 089.5N113W is producing scattered to 
numerous moderate to strong convection from 04N to 14N between 
109W and 117W. Fresh to locally strong winds are found within 
120 nm of the N semicircle to the low, with locally rough seas 
there. Environmental conditions are forecast to be marginally 
favorable for development, and a tropical depression could form 
over the weekend while the system moves west-northwestward or 
northwestward at 5 to 10 mph.
Please refer to the latest NHC Tropical Weather Outlook at 
website: https://www.nhc.noaa.gov/text/MIATWOEP.shtml for more 
details on these systems.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 10N74.5W to 08.5N87W to 09N105W
to 1008 mb low pressure near 08.5N113W to 06N124W to 07N140W. 
Other than the convection described above with three tropical 
waves, scattered moderate isolated strong convection is noted 
from 06N to 14N between 87W and 109W, and from 03N to 11N 
between 117W and 137W. Scattered moderate convection is noted 
from 13N to 17N between 137W and 140W.
...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
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, and for related
convection. 
A modest pressure gradient continues across the Gulf of
Tehuantepec area, where the northern portion of a tropical wave 
has moved W of the Gulf, and is producing strong N to NE gap 
winds in the Gulf and downstream to near 13N98W. Seas are 5 to 8
ft across that area. Across the remainder of the offshore waters
of Mexico, typical ridging has been disrupted by a low level 
trough offshore of Punta Eugenia, along about 118W, resulting in 
a rather weak pressure gradient across the region. Midday 
satellite scatterometer data showed that this current pattern is 
producing mainly light to gentle NW to N winds, except moderate 
near Cabo Corrientes. Seas are 4 to 5 ft across the waters away 
from the Gulf of Tehuantepec. Gentle southerly winds prevail 
across the far northern Gulf of California, and become gentle NW 
to N across the remainder of the Gulf. Seas there are 1 to 3 ft. 
An upper level trough extending offshore of SW Mexico continues 
to support clusters of strong thunderstorms along the coasts and 
nearshore waters of Guerrero and Michoacan, and continue to shift
gradually westward, ahead of an approaching tropical wave.
For the forecast, fresh northerly gap winds will continue to 
pulse to strong winds over the Gulf of Tehuantepec during the 
overnight into the early morning hours through the next several 
days, with seas occasionally building to rough. High pressure 
will begin to build back modestly across the Baja offshore waters
Fri afternoon through Sat night to produce a more typical 
moderate to fresh NW wind flow there. Southerly wind flow will 
return to the Gulf of California Sat night and become fresh to
locally strong Sun. Winds and seas are expected to build across 
the outer offshore waters of southwestern Mexico tonight into 
early next week in association with a developing area of low 
pressure moving westward and just outside of the offshore 
waters.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, 
AND WITHIN 750 NM OF ECUADOR...
Refer to the Tropical Waves section above for details on any
convection.
Recent satellite scatterometer data shows fresh to strong NE to E 
gap extending across the Papagayo region to near 90W, where seas
are 6 to 8 ft. Fresh easterly winds then continue westward and 
downstream, and S of 12.5N, across the outer offshore waters of 
El Salvador and Guatemala, where seas are 6 to 7 ft. Mainly 
moderate or weaker winds are found elsewhere, locally fresh near 
the border of Peru and Ecuador close to the entrance to the Gulf 
of Guayaquil. Seas are 4 to 6 ft across the remainder of the 
waters north of 04N, and 6 to 8 ft south of 04N. Clusters of 
strong thunderstorms are over the waters south of Panama and 
Costa Rica, due to the passing tropical wave there, described 
above.
For the forecast, high pressure will persist over the eastern
Gulf of America and northwestern Caribbean into early next week, 
leading to fresh NE to E gap winds pulsing to strong winds over 
the Papagayo region each evening and night. Moderate to fresh 
winds extending well downwind of Papagayo will impact the outer 
waters offshore of El Salvador and Guatemala through at least 
early next week. South of the monsoon trough, winds will 
gradually diminish and remain light to gentle through the
weekend. Mainly moderate seas will prevail away from the Gulf of
Papagayo area through the next several days. Southeasterly swell
producing rough seas across the southern waters will subside
this evening through Fri.
...REMAINDER OF THE AREA...
Please see the Special Features section and the Tropical Waves 
section above for information on systems that have the potential
for tropical cyclone formation, and any associated convection 
currently present leading to locally higher winds and seas.
High pressure across the NE Pacific extends a ridge south- 
southeastward into the regional waters to offshore of Baja Surf.
Fresh to strong easterly winds and 8 to 10 ft seas associated 
with Tropical Depression Two-C in the Central Pacific basin are 
impacting the waters from 10N to 19N between 138W and 140W. 
Moderate to locally fresh trades are found elsewhere from 10N to
22N between 124W and 140W , where seas are 5 to 7 ft. Moderate 
to locally fresh winds are found south of 06N to the east of 118W
and south of 04N to the west of 120W. Rough seas over the 
southern waters are gradually subsiding, and now cover the 
waters south of 02.5N east of 120W.
For the forecast, regardless of tropical development, the 
features described above will bring increasing winds and seas to
area waters south of 25N, as they move south of the current 
ridge in place. Away from these features, little change is 
expected in marine weather through the next several days, except 
for the rough seas over the southern waters, which are forecast 
to fully subside by the start of the weekend.