Eastern Pacific Tropical Weather Discussion

115
AXPZ20 KNHC 182132
TWDEP 
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 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 1800 UTC surface analysis and satellite imagery through
2000 UTC.
...TROPICAL WAVES...
The axis of a tropical wave is near 86W from 03N northward and 
into the western Caribbean Sea, moving westward at around 15 kt.
Scattered to numerous moderate isolated strong convection is 
noted from 03.5N to 16N between 81W and 90W.
The axis of a tropical wave is near 103W from 03N to 17N, moving
westward at around 20 kt. Scattered to numerous moderate to
strong convection is noted from 06.5N to 14N between 99W and  
109W. An area of low pressure associated with this tropical wave is
forecast to form several hundred 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. This system has
a low chance of tropical formation during the next 48 hours and a
high chance during the next 7 days.
The axis of a tropical wave is near 133W, from 17N southward to 
01N, moving westward at around 15 kt. Scattered to numerous moderate
to strong convection is noted from 00N to 14N between 128W 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. This system has a low 
chance of tropical formation during the next 48 hours and a
medium chance during the next 7 days.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 10.5N75W to 09N95W. The ITCZ 
extends from 09N95.5W to 09.5N103W, then resumes from 08.5N105W 
to 06.5N114W to 10.5N131W, then resumes near 09.5N134W to beyond
09N140W. Other than the convection described above with three 
tropical waves, scattered moderate isolated strong convection is 
noted from 10N to 14N between 90W and 98W. Scattered moderate 
convection is noted from 02.5N to 13N between 109W and 125W.
...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.
High pressure across the NE Pacific extends a ridge south-
southeastward into the regional waters to just west of the
Revillagigedo Islands. The pressure gradient between this ridge
and low pressure across Baja California is yielding moderate to 
fresh NW to N winds across the near and offshore of Baja 
California N of Punta Abreojos. Moderate to fresh SE to S winds 
prevail across central and northern portions of the Gulf of 
California, while winds are variable across the remainder of the 
Gulf. Upper level low pressure across Baja Sur and the adjacent
Pacific waters to support strong thunderstorms shifting 
southward and away from Baja Sur and across Las Tres Marias,
coastal portions of Jalisco, and the adjacent waters to 20N. 
Seas are 4 to 6 ft across the Baja offshore waters, 3 to 5 ft
northern Gulf of California, and 2 to 3 ft inside south and 
central portions of the Gulf.
Further southeast, strong N to NE gap winds continue to gradually
diminish across the Gulf of Tehuantepec, and extend downwind to
near 12N97.5W. Seas there have subsided to 7 to 9 ft in recent
hours. Elsewhere between Cabo Corrientes and Tehuantepec, winds
are light to gentle with moderate seas. Scattered showers and
thunderstorms trailing behind a tropical wave along 103W prevail
south and southwest of Tehuantepec, across the offshore waters. 
For the forecast, northerly gap winds will continue to pulse to 
strong north winds over the Gulf of Tehuantepec each evening and
night through the end of the week. Seas will occasionally build 
to rough during periods of strong winds. Low pressure across Baja
California will sustain a southerly wind flow across the Gulf of
California waters, with fresh to strong winds expected across
northern portions there through Wed before gradually diminishing
through the remainder of the week. Winds and seas will diminish
modestly across the Baja offshore waters through the end of the
week as high pressure weakens. Looking ahead, winds and seas are
expected to build across the outer offshore waters of 
southwestern Mexico by Fri into the upcoming weekend in 
association with a developing area of low pressure, expected to
develop outside of the offshore waters.
...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, 
AND WITHIN 750 NM OF ECUADOR...
Fresh easterly gap winds continue across the Papagayo region 
this afternoon and extend downwind to near 90W. Seas there are 5
to 7 ft. Winds are moderate or weaker elsewhere N of 04N, and 
moderate to fresh south of 04N to the Galapagos Islands. Seas
across most of the area waters are 4 to 6 ft in cross equatorial
S to SW swell, except 7 to 9 ft south through southwest of the 
Galapagos Islands, where SE and SW swell are merging.
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 rest of the week, resulting in rough seas. Moderate 
to fresh winds extending well downwind of Papagayo will impact 
the outer waters offshore of El Salvador and Guatemala at times. 
Moderate to fresh southerly winds south of the monsoon trough and
across the Galapagos waters will gradually diminish through Thu.
Moderate cross-equatorial SW swell moving into the regional 
waters today will continue to merge with large SE swell 
dominating the southern Pacific waters well south of the 
Galapagos to produce rough seas 8 ft and greater S of 01N, and 
moderate seas elsewhere 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.
1031 mb high pressure is centered across the NE Pacific near
147W, and extends a ridge south-southeastward into the regional
waters to just W of the Revillagigedo Islands. Moderate to 
locally fresh NE to E winds are noted from near 10N to 26N 
between 120W and 135W as noted by recent scatterometer data. The 
strongest winds to near 25 kt, and highest seas to 8 ft are 
occurring N of 10N near the tropical wave at 133W. Farther east, 
fresh winds and seas near 8 ft are from 08N to 12N between 101W 
and 105W, and are associated with the tropical wave at 103W. A 
large fetch of strong SE winds across the SE Pacific well south 
through southwest of the Galapagos has generated large SE swell 
that is reaching the equatorial waters between 90W and 130W, 
where SE winds are moderate and seas are 8 to 9 ft. 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 above will bring some increasing winds 
and seas to area waters, as they move south of the current ridge
in place. 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.