000
AXPZ20 KNHC 182240
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Mon May 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
2100 UTC.

...SPECIAL FEATURES...
Significant Swell Event West of Baja California Norte: 
large, long-period NW swell is maintaining very rough seas of 12
to 13 ft, north of 27N between 118W and 127W, including waters
just west of Guadalupe Island. This swell will continue to decay
and retreat northward through late Tue, which should allow seas
to subside below 12 ft after midnight tonight.

Please refer to the latest High Seas and Offshore Waters 
Forecasts issued by the National Hurricane Center at websites: 
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and
https://www.nhc.noaa.gov/marine/offshores_eastpac.php for more 
details.

...TROPICAL WAVES...

A tropical wave is near 81W from the western Caribbean Sea
southward across western Panama into the eastern Pacific, and 
moving west at 5 to 10 kt. It is enhancing convection near the 
monsoon trough described in the section below.

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

A monsoon trough extends west-southwestward from central Costa
Rica to 07N91W. An ITCZ continues westward from 07N91W to 
07N120W to beyond 07N140W. Scattered moderate to isolated strong
convection is active near and south of the monsoon trough from 
02N to 11N east of 88W, including offshore waters of Costa Rica,
Panama and Colombia. Similar convection is present near the ITCZ
from 05N to 12N between 93W and 117W. Numerous moderate to
scattered strong convection is noted near the western portion of
the ITCZ from 03N to 11N west of 118W.

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

Please read the Special Features section above regarding  
Significant NW swell.

A broad surface ridge has shifted farther west to near 130W this
evening, which allows NW to N winds near Baja California and the
Revillagigedo Islands to become gentle to moderate. Residual
large, long-peroid NW swell is keeping seas at 10 to 13 ft west
of Baja Norte, at 7 to 10 ft west of Baja Sur, and at 5 to 7 ft
near the Revillagigedo Islands. Gentle to moderate SE to SW to 
NW winds with 2 to 4 ft seas dominate the Gulf of California. 
Light to gentle winds and seas of 4 to 5 ft in mixed moderate 
swell prevail for the central and southern Mexico offshore 
waters, except at the far southern waters off Chiapas State, 
where moderate E winds persist.

For the forecast, residual large, long-period NW swell will 
maintain 10 to 12 ft seas off Baja Norte until midnight tonight, 
then subside to between 6 and 8 ft by Tue afternoon. Seas of 8 to
11 ft near Baja Sur will also drop to between 6 and 8 ft by Tue 
afternoon. Winds near Baja California and the Revillagigedo 
Islands, and in the Gulf of California will become mostly gentle 
this evening, and stay this way most of this week. The only 
exception will be moderate with locally fresh NW winds off Cabo 
San Lucas in the night-time and early morning hours.
 
....OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA,
AND WITHIN 750 NM OF ECUADOR...

Fresh with locally strong NE to E gap winds and seas of 6 to 8 ft
are persisting in the waters off the Papagayo region. Fresh E winds
and 5 to 6 ft seas are seen farther downstream across the southern
offshore waters of Guatemala and El Salvador. Otherwise, mainly 
gentle winds and seas at 2 to 4 ft are seen for the rest of the
central America offshore waters. Gentle to moderate SE to SW
winds with 4 to 5 ft seas in moderate southerly swell prevail off
Colombia and Ecuador, and near the Galapagos Islands. Refer to
the Intertropical Convergence Zone/Monsoon Trough section above
for convection in the region.

For the forecast, fresh easterly gap winds in the Papagayo region
will pulse to strong during the night-time hours through Wed 
night. Elsewhere, gentle to moderate winds along with moderate 
seas in southerly swell are expected through most of this week. 
Scattered heavy showers and isolated thunderstorms will linger in
the offshore waters of Costa Rica, Panama and Colombia through 
tonight.

...REMAINDER OF THE AREA...

A broad surface ridge extends southwestward from a 1034 mb high
near 38N140W across 30N136W to near the Revillagigedo Islands.
This feature is supporting moderate to fresh N to NE winds north
of the ITCZ west of 120W. Under long-period, large to moderate NW
swell, seas in this area range from 7 to 13 ft, with the highest
near 29N123W. For the waters north of the ITCZ east of 120W, 
gentle to moderate NNE to E winds with 5 to 8 ft seas in mixed 
moderate swells exist. Gentle to moderate SE to E winds and seas
at 5 to 8 ft in mixed moderate swells prevail south of the ITCZ.

For the forecast, the aforementioned ridge will continue to 
gradually weaken while shifting westward through midweek. This 
will allow winds and seas north of the ITCZ to steadily subside 
from east to west through midweek, becoming gentle to moderate 
winds with 6 to 8 ft seas by Thu. Winds south of the ITCZ will 
also becoming gentle by Thu with seas staying at 5 to 7 ft in 
mixed swells.

$$

Chan