Skip Navigation Links
NOAA NOAA United States Department of Commerce

Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 220904

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Fri Oct 22 2021

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
0900 UTC.


Gale warning: A gale warning is in effect for developing low
pressure centered approximately 220 nm south of Acapulco, Mexico.
Showers and thunderstorms near the low are becoming better
organized, and there is a high chance a tropical depression will
form over the next couple of days. Regardless of development,
mariners can expect gales and rough seas in the offshore waters from
western Oaxaca to Michoacan through Mon. Please see latest 
Tropical Weather Outlook at

The monsoon trough extends from 09N79W to 1009 mb low pressure
near 13N99W to 09N105W to 1012 mb low pressure near 12N117W to
08N131W to 10N140W. Scattered moderate convection is observed in
the Gulf of Panama. Numerous moderate to isolated strong
convection is noted from 10N to 16N between 92W and 12W. 
Scattered moderate to isolated strong convection is evident from 
10N to 14N between 113W and 121W.


Please see the Special Features section regarding the developing
low pressure area off southern Mexico.

A surface ridge extends from 1024 mb high pressure centered near
28N125W to south of Los Cabos. Moderate to occasionally fresh NW
winds persist between the ridge axis and lower pressure over
north central Mexico. A radar altimeter satellite pass from 03
UTC confirmed 8 to 9 ft seas were already impacting the offshore
waters of Baja California. This is part of a larger area of NW 
swell in excess of 8 ft propagating into the region.  

For the forecast, in additional the high likelihood of a 
tropical depression forming off southern Mexico over the next 
couple of days, NW swell in excess of 8 ft moving into the 
offshore waters of Baja California Norte will subside later 
today. However, another set of large NW swell will follow 
tonight, reach as far south as Socorro Island by Sun, then 
subside through late Mon. Looking ahead, a third round of NW 
swell may reach Baja California Norte waters Mon, reaching 
Socorro Island by Tue night. 


Mainly gentle to moderate S to SW will follow the 
monsoon trough as it lifts north of the area over the next couple
of days. By Sat night into Sun, expect building seas in SW swell
between Ecuador and the Galapagos Islands. This swell event is 
forecast to reach the offshore forecast waters of western Panama 
on Sun, supporting seas to 8 ft. Seas will subside thereafter
across the region.


1024 mb high pressure centered near 28N125W is shifting east ahead
of a cold front moving across waters north of 25N over the next 
couple of days. Large, long period NW swells follow the front 
forecast to reach 30N128W to 27N140W later today, and from 
30N119W to 26N140W on Sat while weakening. Moderate to fresh SW 
winds are between the front and the high. Currently, seas of 8 to
11 ft in NW swell cover the area northwest of a line from 
Guadalupe Island to 14N140W. Highest seas of 12 to 15 ft are 
expected in the wake of the front this morning. This swell event
will continue to propagate across the forecast region through at
least Sat, with seas in excess of 8 ft covering much of the 
waters N of 20N W of 120W. 

Looking ahead, another large area of NW swell will move south of
30N Sun night, bring seas in excess of 8 ft to most of the area 
west of 110W through mid week.