000
AXPZ20 KNHC 260242
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Tue Sep 26 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
0240 UTC.

...TROPICAL WAVES...

A tropical wave is analyzed along 120W from 04N to 17N, moving W
at 10 to 15 kt. No significant convection is evident at this time
near the wave axis.

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

The monsoon trough extends from 10N85W to 10N115W. The ITCZ 
extends from 11N130W to 10N140W. Scattered moderate convection is
evident from 10N to 12N between 91W and 93W, and from 08N to 10N
between 104W and 108W.

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

A surface ridge extends from 1018 mb high pressure centered near
29N125W to Baja California Sur. Various ship observations from
the past several hours showed fresh NW winds off Baja California,
and combined seas there are likely 5 to 7 ft. The pattern is also
supporting moderate to fresh NW winds over the central Gulf of
California, with lighter winds elsewhere. Gentle breezes are
noted farther south, with 3 to 5 ft seas. A cluster of
thunderstorms is active about 90 nm off the Michoacan coast. 

For the forecast, 

A modest surface ridge continues to dominate the offshore 
forecast waters of Baja California, centered on a 1021 mb high 
near 30N124W. This pressure pattern is supporting mainly fresh 
NW-N winds from near Cabo San Lazaro northward. Seas are 5-7 ft 
in NW swell offshore Baja California. Inside the Gulf of
California, N-NW winds have increased to fresh across central 
portions between 26N and 28N, where seas have built to 4 ft. 
Winds are moderate or weaker elsewhere, with seas of 4-5 ft, 
except 1-2 ft in the northern Gulf of California. Scattered 
moderate to strong convection persisting across the coastal 
waters of southwestern Mexico continues from 13N to 16N between  
98W and 102W.

For the forecast, fresh NW winds will persist off Baja 
California north of Cabo San Lazaro into mid week between high 
pressure north of the area and a trough over the Gulf of 
California. Winds will then gradually diminish Wed through Fri as
the ridge shifts NW. Seas will build 8 to 12 ft in new NW swell 
offshore Baja California Tue through Thu before slowly subsiding 
Fri through Sat. Farther south, moderate to fresh N gap winds 
will pulse to strong across the Gulf of Tehuantepec Tue night. 
Looking ahead, fresh to strong westerly gap winds are possible 
over the northern Gulf of California late Sat ahead of an 
approaching cold front.

...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, 
COLOMBIA, AND WITHIN 750 NM OF ECUADOR...

Light and variable breezes are evident off northern Central 
America, north of the monsoon trough, with gentle SW breezes
noted farther south. Combined seas are 3 to 5 ft across the
region with a component of southerly swell. Scattered showers and
thunderstorms are evident beyond 90 nm offshore of Nicaragua and
El Salvador. A few showers and thunderstorms are starting to
develop closer to shore in the Gulf of Papagayo and off southern
Nicaragua. 

For the forecast, gentle to moderate winds prevail to the north 
of 07N with seas 5 ft or less through Sat night. Gentle SW winds 
farther south will increase to moderate mainly south of 05N 
starting late Tue, with combined seas building to 6 to 8 ft in 
southerly swell off Ecuador. 

...REMAINDER OF THE AREA...

The remnants of T.C. Fourteen-E are fully exposed near 15N131W 
as a 1010 mb. An earlier scatterometer satellite pass indicated fresh
to strong winds are still accompanying the low on the northern
semicircle, implying rough seas near the low pressure as well.
Farther north, and altimeter satellite pass from 23 UTC showed
seas to 9 ft near 30N140W. This is indicative of long-period NW
swell reaching the discussion waters ahead of a cold front moving
through the north-central Pacific. Altimeter data also resolved
combined seas to 7 ft farther south, part of a large area of
southwest cross-equatorial southerly swell moving into the waters
south of 03N and west of 100W. Meanwhile earlier convection near
the tropical wave at 119W has diminished, but convection has
intensified near 08N105W south of the monsoon trough. 

For the forecast, the remnants of T.C. Fourteen-E will weaken to
a trough during the next 48 hours while moving west-southwestward.
The cold front approaching 30N140W will stall and dissipate north
of 28N and west of 135W into mid week. High pressure north of 
the front will increase the pressure gradient to the west of 
125W, and freshen the winds Tue through Thu. This will also 
coincide with the arrival of large NW to N swell generated across
the NE Pacific in recent days. This swell will push into the 
northern waters this afternoon, building seas to 7-11 ft north 
of 10N and west of 115W by the middle of the week. Elsewhere, 
weak high pressure will prevail N of the monsoon trough and E of 
120W through Wed and yield moderate or weaker winds. 

Looking ahead, another pulse of SE swell will enter the area S 
of the equator by mid week and spread northward through Fri.

$$
Christensen