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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 300213

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Fri Sep 29 2023

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 0000 UTC surface analysis and satellite imagery through
0150 UTC.


A tropical wave is along 98W north of 06N, moving west at around
10 kt. Scattered moderate convection is noted from 06N to 13N
between 93W and 101W.


The monsoon trough extends from 10N75W to 11N113W. The ITCZ 
extends from 11N113W to 10N127W to 11N140W. Scattered moderate 
isolated strong convection is noted from 04N to 11.5N between 80W
and 93W, from 06N to 13N between 108W and 116W, and from 05N to 
16N between 123W and 140W.


Surface ridging extends across the offshore waters of Mexico with
a surface trough along the Baja California Peninsula. Fresh to
strong N winds are noted in the immediate Gulf of Tehuantepec.
Fresh to strong S-SW winds are developing in the northern Gulf of
California due a tightening pressure gradient. Winds are 
moderate or weaker elsewhere. Seas are 6-9 ft in decaying NW 
swell offshore Baja California, and 4-6 ft elsewhere in the open 
waters. In the Gulf of California, seas are 1-3 ft except 3-4 ft 
near the entrance. A tropical wave is moving across portions of
southern Mexico as described above. 

For the forecast, the NW swell offshore Baja California will
continue to decay through Sat. Otherwise, mainly moderate seas 
will prevail. Fresh to strong N winds will pulse in the Gulf of 
Tehuantepec, mainly at night, through the weekend. Fresh to 
strong SW winds will pulse in the northern Gulf of California 
through Sun night due to a passing pre-frontal trough and 
weakening cold front. Winds will be moderate or weaker elsewhere.
Looking ahead, an area of low pressure is expected to form well 
south of the coast of southwestern Mexico early next week. 
Environmental conditions are expected to support at least gradual
development of the disturbance and a tropical depression could 
form during the middle to later part of the week while the system
moves generally northwestward.


Gentle winds are N of the monsoon trough with moderate S-SW 
winds S of the monsoon trough. Seas are 3-5 ft N of 10N as well 
as offshore Colombia to the Azuero Peninsula, and 4-7 ft in SE-S 
swell S of 07N, except 5-8 ft offshore Ecuador to the Galapagos 
Islands, highest S of the Galapagos Islands. Widely scattered 
showers and isolated thunderstorms are offshore western Panama 

For the forecast, winds will be moderate or weaker across the
offshore waters through the next several days. The southerly
swell will gradually decay into the weekend, then may build
back offshore Ecuador to the Galapagos Islands by the middle of 
next week. Otherwise, expect moderate seas to prevail across the 


A strong high pressure N of the monsoon trough/ITCZ is 
supporting fresh to strong winds from 12N to 19N and W of 137W. 
Moderate to fresh trades prevail elsewhere N of 12N and W of 
128W. Winds are moderate or weaker elsewhere. A large area of 
8-12 ft seas dominates the waters from the Equator to 23N and W 
of 105W in mixed SE and NW swell. Seas are 8-11 ft in more pure 
SE-S swell S of the Equator and W of 95W. Seas are 4-7 ft across 
the remainder of the open waters.

For the forecast, fresh to strong winds will diminish by early 
Sat. Winds of moderate or weaker will prevail elsewhere through 
the next several days. The elevated seas W of 105W will 
gradually decay through the weekend. A decaying cold front will 
push S of 30N this weekend with seas building to around 8 ft just
S of 30N Sun afternoon into early next week. The southerly swell
will decay slightly by the end of the weekend, however 7-9 ft 
seas will linger S of the Equator through early next week.