426 
AXPZ20 KNHC 230132
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Mon Dec 23 2024

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
0100 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: The pressure gradient between 
persistent high pressure over eastern Mexico and low pressure 
within the eastern north Pacific monsoon trough will continue to 
support gale-force gap winds in the Gulf of Tehuantepec through
tonight. Presently, strong N to NE winds extend beyond the 
Tehuantepec coast to near 250 nm offshore. Seas within and just 
downwind of the gale force winds at expected to peak near 13 ft.
The high pressure will shift east by early Mon and weaken across
Mexico, with the pressure gradient loosening. This will cause 
winds to diminish below gale force by early Mon with fresh to 
strong northerly pulses thereafter into Tue night, then moderate
to fresh through Wed before diminishing. Please see the latest 
NWS High Seas and Offshore Waters Forecasts issued by the 
National Hurricane Center at website:
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and 
www.nhc.noaa.gov/marine/offshores_eastpac.php for more 
details.

Significant NW swell: A large, complex, and powerful low 
pressure system north of the area will move NE through tonight, 
followed by another similar low pressure system sweeping just 
north of the area waters Mon through Tue. These systems are 
generating several rounds of large NW swell that will propagate 
into the area through the week and into next weekend. This 
evening, seas greater than 12 ft cover the waters west of a line
from near Punta Eugenia in Baja California to 07N133W. This 
large NW swell will continue to spread SE through Mon while
decaying while a reinforcing set quickly moves in behind. The 
large swell will peak across the offshore waters of SW Mexico
mid-week, and just beyond the offshore waters of Central America
thereafter. Peak seas will be around 22 ft tonight near 30N140W. 
Please see the latest NWS High Seas Forecast issued by the 
National Hurricane Center at website:
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details.

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

The monsoon trough extends from 09N84W to 06N108W. The ITCZ
extends from 06N108W to 07.5N127W to beyond 06N140W. Scattered
moderate convection is noted from 02N to 09N between 79W and 93W,
and from 06N to 09N between 130W and 134W.

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

Please read the Special Features Section for information on a 
Gale Warning in the Gulf of Tehuantepec, and significant NW 
swell that will impact the waters offshore Baja California 
through the week and into next weekend.

Aside from those conditions, 1024 mb high pressure is centered 
near 27.5N127.5W, with an associated ridge extending 
southeastward to offshore of Cabo Corrientes. The pressure 
gradient between this area of high pressure and a trough over NW 
Mexico is supporting moderate northerly winds across the Baja 
California waters, while gentle to moderate winds prevail south 
of 20N to offshore of Manzanillo and inside the Gulf of 
California. Seas are in the 4 to 7 ft over the open waters off 
Mexico to near Cabo San Lucas. Elsewhere across the Baja waters,
seas are 8 to 15 ft from Punta Abreojos north and northwestward.
Seas are 3 ft or less inside the Gulf of California.

For the forecast, other than the aforementioned Gale Warning in 
the Tehuantepec region and the significant NW swells, high 
pressure west of the area will maintain moderate northerly winds 
pulsing to fresh at times offshore of Baja California through 
Tue, then becoming fresh to strong from Cabo San Lazaro northward
Tue night through Thu night, with gentle to moderate winds 
across the remainder of the waters. Fresh to strong winds will be
in the northern Gulf of California late Tue night through Wed as
a cold front moves through the region. Significant NW swell will
continue to spread southeastward to impact most waters through 
the week. Peak seas of 15 ft or higher offshore of north and 
central Baja California are expected this afternoon and tonight, 
peaking across south and central Baja offshore waters Mon and 
Tue. 

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

The pressure gradient between a surface ridge extending southward over
the western Caribbean Sea and the EPAC monsoon trough is supporting
fresh to strong NE gap winds in the Papagayo region. Seas are 5 
to 7 ft across this area. Gentle to moderate winds prevail 
elsewhere north of the monsoon trough, with moderate to fresh
winds in the Gulf of Panama. South of the monsoon trough and 
07N, gentle to moderate S to SW winds and 3 to 5 ft seas in 
moderate S to SW swell prevail, except for seas of 6 to 9 ft 
well offshore of western Guatemala, where NW swell from the Gulf 
of Tehuantepec gap wind event persists. Weak 1009 mb low 
pressure is south of the Gulf of Panama near 06N79W. Active 
convection is present S of 07.5N from the coast of Colombia 
westward across the near and offshore waters of Panama and Costa 
Rica, and extends beyond 90W.

For the forecast, the pressure gradient between high pressure 
extending southward over the western Caribbean and the eastern 
north Pacific monsoon trough will support fresh gap winds pulsing
to strong winds in the Papagayo region into Tue, then moderate 
to fresh thereafter. Gales in the Tehuantepec region will 
generate northerly swell and rough seas well offshore Guatemala 
through tonight. Elsewhere, winds will be moderate or weaker with
moderate seas through mid-week, pulsing to moderate to fresh in 
the Gulf of Panama at times. A surge of at least fresh NW to N 
winds may move across the offshore waters of Guatemala mid- week.
Seas will build Wed as the strong NW swell moves into the 
regional waters.

...REMAINDER OF THE AREA...

Please read the Special Features section about large NW swell 
over the waters north of the Monsoon Trough/ITCZ through the 
next several days.

A cold front is just north of the NW waters with moderate to
fresh SW winds occurring over the waters just southeast of
30N140W. High pressure of 1024 mb is ahead of the front near 
27N127.5W. Light to gentle anticyclonic winds are elsewhere 
north of 23N and east of the front to 120W. The pressure 
gradient between the high pressure and lower pressure in the 
vicinity of the ITCZ is supporting moderate to fresh winds north 
of the ITCZ to 23N and west of 118W, and locally strong within 
210 nm of the ITCZ west of 123W. Across the remainder of the 
open waters, including south of the ITCZ, gentle to moderate 
trades prevail. Aside from the large swell discussed above, seas 
are mainly in the 5 to 8 ft range, except 6 to 9 ft downwind of
the Tehuantepec region due to a gale-force gap wind event.

For the forecast, other than the large NW swell discussed in 
detail in the Special Features sections, little significant change
in winds are forecast over the next several days, while a front 
manages to push SE of 30N140W Mon, decaying over the northern 
waters into mid-week. New high pressure will build into the 
region behind this front and increase trade winds to fresh to
strong west 130W Mon night through mid-week. Meanwhile, seas of 
8 ft or greater will cover most of the waters west of 110W by 
Mon evening, then west of 100W Tue evening, then west of 90W Wed
evening.

$$
Lewitsky