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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 310403

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Tue Jan 31 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
0345 UTC.


The monsoon trough axis extends from northwestern Colombia
westward to southern Costa Rica and to the coast near 09N85W to 
06N93W and to 06N100W. The ITCZ extends from 06N100W to 08N108W 
to 06N115W to 07N124W to 06N131W and to 07N140W. Scattered
moderate convection is within 60 nm north of the ITCZ between 
106W-109W, also between 115W-121W and within 60 nm south of the
ITCZ between 134W-137W.


Satellite imagery shows weak low pressure of 1011 mb located
about 60 nm west of the border between southern California and 
Baja California Norte. An occluded front extends from the low to 
30N117W, where it transitions to a cold front to 26N120W, and 
continues to 25N125W and northwestward to 27N131W and to 30N137W.
Fresh northwest to north winds are north of the cold front, 
except for an area of fresh to strong northwest winds noted north
of 27N and between 120W-125W. Seas over these waters are in the 
7-10 ft range due to a long period NW swell. Gentle to moderate 
northerly winds and seas of 4-6 ft prevail in the remainder of 
the Baja California offshore waters, except for moderate to fresh
W to NW winds from 26N to 27N. Satellite imagery also indicates 
broken to scattered low and mid-level clouds with possible 
shower activity offshore extreme southern California and northern
Baja California Norte.

Moderate to fresh southerly winds are found in the northern Gulf
of California. Seas in the waters described are 2-4 ft. Light to
gentle winds and seas of 1-3 ft prevail in the rest of the Gulf
of California. Elsewhere in the Mexican offshore waters, gentle 
to moderate variable winds and moderate seas are prevalent.

For the forecast, the aforementioned cold front will sweep 
southeastward across the Baja California peninsula and Gulf of 
California tonight through Tue evening while weakening. Fresh to 
strong NW winds behind the front are expected to reach near 28N 
tonight, but be just west of the offshore waters. These winds 
will diminish to fresh speeds late tonight. Otherwise, high 
pressure in the wake of the front will shift E along 30N through 
Thu, with winds diminishing and seas subsiding. The next Gulf of 
Tehuantepec gale force gap wind event is possible starting at the
end of the week. This event is expected to be on the high range 
of gale force winds, with some chance of winds reaching storm 


Fresh to strong easterly trade winds remain in the Gulf of 
Papagayo, and Nicaraguan offshore waters. The strong winds extend
westward to near 89W. Seas are 6-8 ft in the waters described, 
with the maximum seas in the Gulf of Papagayo region. A recent 
altimeter satellite pass depict seas to 8 ft near 10N88W. 
Moderate to locally fresh N winds are found the Gulf of Panama, 
extending southward to about 03N. Seas in these waters are 3-6 
ft. Elsewhere, light to gentle winds and seas 4-6 ft in S to SW 
swell prevail.

For the forecast, the fresh to strong trade winds in the Gulf of
Papagayo region will prevail through the rest of the week and 
into the upcoming weekend. Pulsing fresh to locally strong N 
winds in the Gulf of Panama will diminish to moderate speeds Thu 
into the weekend.


The subtropical ridge remained located well northwest of the 
eastern tropical Pacific, extending weakly southeastward to the 
Revillagigedo Islands. Satellite imagery reveals a cold front 
that extends from weak low pressure within 60 nm offshore the 
border between extreme southern California and northern Baja 
California, then southwestward to beyond the outer limits of
the Mexican offshore waters at 27N120W and continues to 25N125W
and northwestward from there to 27N131W and to 30N137W. Fresh 
northwest to north winds are north of the cold front, except for
an area of fresh to strong northwest winds noted north of 27N 
and between 120W-125W. Winds become moderate to fresh NE to E in 
direction north of the front and west of 131W. Seas over these 
waters are in the 8-11 ft due to a long-period NW swell mixing
with NE to E wind waves. Fresh easterly trade winds are present 
between the ITCZ and the cold front, and also from the ITCZ to 
26N west of 137W. Seas are 7-10 ft over these waters due to NW to
N swell mixing with the waves generated by the easterly winds. 
Elsewhere, gentle to moderate winds and moderate seas prevail 
remainder of the basin.

For the forecast, the NW swell propagate through the north-
central and NE waters is expected to build seas to 12 ft near
29N123W tonight. An area of fresh to strong NW winds is N of 
of 27N and between 120W-125W, with seas of 8-11 ft. The moderate
to fresh trade winds will continue through late Wed, however, an
area of fresh to strong NE trade winds is expected to develop 
from about 09N to 17N and between 114W-128W as the gradient 
tightens between troughing that sets up roughly from near 17N114W
to 11N116W, and the aforementioned high pressure that will be 
shifting E along 30N in response to a cold front that will be 
entering the far NW part of the area at that time. This cold 
front is expected to be preceded by fresh to strong S to SW winds
and seas of around 8-10 ft.