Eastern Pacific Tropical Weather Discussion

687
AXPZ20 KNHC 200706
TWDEP 
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 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 0600 UTC surface analysis and satellite imagery through
0610 UTC.
...SPECIAL FEATURES...
Central Pacific (EP90): An area of low pressure, Invest EP90, 
has fully crossed over into the Central Pacific basin to the west
of 140W, currently near 11N141W. While outer winds and seas 
still extend just to the east of 140W into the discussion waters,
winds east of 140W are forecast to remain below warning 
criteria. Please refer to the latest NHC Tropical Weather Outlook
at website:
https://www.nhc.noaa.gov/text/MIATWOEP.shtml for more details.
...TROPICAL WAVES...
The axis of a tropical wave is just east of the area over
portions of western Colombia and moving from the central to the
western Caribbean Sea near 76W, moving westward at 15 to 20 kt.
Scattered moderate isolated strong convection is noted from 06N 
to 11N between 77W and 89W.
The axis of a tropical wave is near 96.5W from 01N to 17N just
west of the Gulf of Tehuantepec over portions of Oaxaca, or a 
few hundred nautical miles south of the coast of southern Mexico,
is moving westward at 15 to 20 kt. Scattered to numerous 
moderate to strong convection is noted from 05N to 14N between 
89W and 98W. A tropical depression is likely to form this weekend
while the system moves generally west-northwestward, remaining 
well offshore of Mexico. This system has a low chance of tropical
cyclone formation in the next 48 hours, and a high chance in the
next 7 days. Regardless of development, expect increasing winds 
and seas to impact the outer offshore waters of southwestern 
Mexico. 
The axis of a tropical wave is near 111W from 01N to 16N, moving
westward at around 15 to 20 kt. A broad area of low pressure 
associated with this tropical wave near 08N111W is producing 
disorganized showers and thunderstorms several hundred nautical 
miles south of the southern tip of the Baja California Peninsula.
Scattered to numerous moderate to strong convection is noted 
from 05N to 12N between 106W and 115W. Winds are currently fresh 
with locally rough seas there. Environmental conditions are 
forecast to be marginally favorable for gradual development over 
the weekend as the system moves westward or west- northwestward 
at 5 to 10 kt.
Please refer to the latest NHC Tropical Weather Outlook at 
website:
https://www.nhc.noaa.gov/text/MIATWOEP.shtml for more details on
both systems.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 1007 mb low pressure over
northern Colombia at 11N75W to 08.5N90W to 1009 mb low pressure
near 08N111W to 07N125W to 10N140W. Other than the convection 
described above with three tropical waves, scattered moderate 
isolated strong convection is noted from 04N to 11N between 129W 
and 133W. Scattered moderate convection is noted from 10N to 17N 
between 130W and 140W, mainly related to Invest EP90 which has 
crossed over into the Central Pacific basin.
...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 tight pressure gradient continues over the Gulf of Tehuantepec
where the northern portion of a tropical wave is just passing 
by, and is producing strong N to NE gap winds in the Gulf. Recent
ASCAT scatterometer data confirmed these winds. Resultant seas 
of 5 to locally 8 ft. Across the remainder of the offshore waters
of Mexico, typical ridging has been disrupted by a surface trough
from Baja California Norte to the southwest resulting in a rather
weak pressure gradient across the region and mainly light to
gentle winds, except moderate from near Cabo Corrientes up the
coast toward the entrance of the Gulf of California as seen by
the same ASCAT data. Seas are 4 to 6 ft across the waters away
from the Gulf of Tehuantepec, and 1 to 3 ft inside the Gulf of 
California. A thunderstorm complex is evident on conventional
infrared satellite imagery near the boast of western Oaxaca and
Guerrero.
For the forecast, northerly gap winds will continue to pulse to 
strong north 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. Low pressure 
across Baja California will sustain a southerly wind flow across 
the Gulf of California waters. Winds may freshen across the Gulf
of California Sat night through Sun night, and also freshen
nearshore Baja California Fri night through Sat as the pressure
gradient tightens a bit. Looking ahead, winds and seas are 
expected to build across the outer offshore waters of 
southwestern Mexico by tonight into early next week in 
association with a developing area of low pressure moving by 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 ASCAT scatterometer passes missed the immediate Gulf of
Papagayo where fresh to strong easterly gap winds are likely
occurring, however they did measure moderate to fresh easterly
winds well downwind across the outer offshore waters of El
Salvador and Guatemala to the south of 12.5N, with seas of 5 to
locally 8 ft from Offshore Gulf of Papagayo to near 11N96W. 
Mainly moderate or weaker winds are found elsewhere, locally 
fresh near the border of Peru an Ecuador close to the entrance to
the Gulf of Guayaquil. Seas are 4 to 7 ft across the remainder of
the waters north of the Equator, and 6 to 8 ft south of the
Equator, except to 9 ft near the Gulf of Guayaquil as measured by
a recent Sentinel-3B altimeter pass. Some isolated to widely
scattered showers and thunderstorms are over the waters south of
Panama to off Costa Rica, as well as offshore Guatemala due to
the passing tropical wave there, described more above.
For the forecast, the pressure gradient between high pressure 
over the northwestern Caribbean and relatively lower pressure 
over Central America will lead to fresh NE to E gap winds pulsing
to strong winds over the Papagayo region each evening and night 
through the early next week, resulting in rough seas at times. 
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. Any lingering moderate to 
locally fresh southerly winds south of the monsoon trough and 
across the Galapagos waters will gradually diminish today. Mainly
moderate seas will prevail away from the Gulf of Papagayo area
through the next several days, dominated by long period southerly
swells. Seas may be locally rough south of the Equator early
today.
...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 just northwest of the 
Revillagigedo Islands, however it is now disrupted by a surface 
trough analyzed from 30N135W to 23N140W which was nicely evident
in a recent ASCAT scatterometer pass. Outer fresh to strong 
winds and 8 to 11 ft seas associated with Invest EP90 now west of
the area in the Central Pacific basin are impacting the waters 
from 11N to 16N between 137W and 140W. Moderate to locally fresh 
trades are found elsewhere from 14N to 23N between 128W and 140W.
Moderate to locally fresh winds are found south of 06N to the 
east of 120W and south of 02N to the west of 120W. Rough seas 
over the southern waters are decaying, now over the waters south 
of 02N and east of 130W, up to 9 ft south of the Equator and east
of 110W.
For the forecast, regardless of tropical development, the 
features described above will bring some 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 to moderate levels by the start of the
weekend.