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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 221553

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.


A new tropical depression has formed SW of southern Mexico and it
is forecast to strengthen to a hurricane over the next couple of
days. AT 22/1500 UTC, Tropical Depression Seventeen-E is centered
near 12.7N 100.5W moving W at 9 kt. Estimated minimum central 
pressure is 1007 mb. Maximum sustained wind speed is 30 kt with 
gusts to 40 kt. On the forecast track, the system would be 
approaching the coast of southwestern Mexico early next week.
Strengthening is forecast, and the depression is expected to become 
a tropical storm by tonight, and a hurricane over the weekend.
Tropical Depression Seventeen will produce 5 to 10 inches of 
rain with isolated storm total amounts of 15 inches across 
coastal sections of the Mexican states of Guerrero, Michoacan, 
and Colima starting Saturday night. This will likely produce 
flash flooding and mudslides.

Please read the latest HIGH SEAS FORECAST issued by National
Hurricane Center at website and the latest 
Tropical Depression Seventeen-E NHC Forecast/Advisory and Public
Advisory at for more details.

The monsoon trough extends from 10N85W to Tropical Depression
Seventeen-E located near 12.7N 100.5W to 11N110W to 1010 mb low 
pressure situated near 11N119W to 09N129W. The ITCZ continues 
from 09N129W to beyond 07N140W. Aside for the convection
associated with Tropical Depression Seventeen-E, scattered
moderate isolated strong convection is noted from 05N to 10N
between 79W and 85W, near 11N89W, and from 07N to 13N between
105W and 130W. 


A new tropical depression has formed SW of southern Mexico.
Please, see the Special Features section for more details.

A surface ridge extends from 1022 mb high pressure centered near
26N132W to near the Revillagigedo Islands. Moderate to occasionally
fresh NW winds persist between the ridge axis and lower pressure
over north central Mexico. An altimeter pass confirmed 8 to 9 ft
seas were already impacting the offshore waters of Baja California
N of Cabo San Lazaro. This is part of a larger area of NW swell 
in excess of 8 ft propagating into the region. 

For the forecast, please, see the Special Features section for 
more details on Tropical Depression Seventeen-E. Elsewhere, 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 


A cold front is moving across the NW corner of the forecast
region and extends from 30N130W to 27N140W. A 1022 mb high 
pressure centered near 26N132W is shifting east ahead of a cold 
front. Large, long period NW swells follow the front forecast to
reach from 30N119W to 26N140W by Sat morning while weakening. 
Moderate to fresh SW winds are between the front and the high. 
Currently, seas of 8 to 12 ft in NW swell cover the area 
NW of a line from 30N128W to 25N140W. Highest seas of 12 to 15 
ft are noted NW of a line from 30N132W to 27N140W. An altimeter
pass just W of 140W confirmed the presence of these sea heights.
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.