426 
AXPZ20 KNHC 300944
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Sat Dec 30 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 0600 UTC surface analysis and satellite imagery through
0930 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: Strong high pressure building 
across the western Gulf of Mexico behind a strong cold front is
forcing gale force winds across the Gulf of Tehuantepec. The 
gale force northerly gap winds are expected to persist through 
tonight, diminishing by early Sun morning. Seas will build to 12
ft in the next few hours. Seas will then subside by Sun night 
across the region. Strong winds will also briefly subside by
early Mon morning.

Very Large Swell Event Across Eastern Pacific: A cold front 
stretches across Eastern Pacific from 30N122W to 21N134W.
Moderate winds are noted behind the front confirmed by
scatterometer. Meanwhile, very large NW swell is associated with
this system, with the highest seas of 20 ft noted N of 26N 
between 123W and 135W. The 12 ft seas extend as far south as 04N
and as far east as 110W, including to the coastline of Baja 
California. The 8 ft seas extend even farther south to the 
Equator and as far east as 106W. The front will dissipate tonight
over the Baja California offshore waters. However, the reinforcing
swell will continue to spread south and east across the waters 
over the next few days. Seas will subside below 20 ft this 
morning. The 12 ft seas will subside by Sun night, and continue 
to gradually subside through early next week. 

Please refer to the High Seas Forecast issued by the National 
Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml
for details.

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

The monsoon trough extends from the coast of Costa Rica near
09N84W to 04N96W. The ITCZ continues from 04N96W to 06N120W to 
beyond 06N140W. Scattered moderate convection is noted from 03N 
to 10N between 104W and 140W. 

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

See the Special Features Section above for details on a Gale 
Warning for the Gulf of Tehuantepec.

A 1022 mb high pressure is centered to the west of the Baja 
California offshore waters near 25N122W. The ridging from this 
high extends across most of the offshore waters of Mexico. The 
pressure gradient between this high pressure and lower pressure 
over Mexico is supporting moderate NW winds across the central 
and southern Gulf of California with seas 2 to 4 ft. Meanwhile, 
gentle to moderate N winds are noted in the Baja California and 
southwest Mexico offshore waters. A large NW swell event is 
impacting the waters west Baja California with seas of 10 to 14 
ft. Seas of 8 ft or greater in NW swell likely extend as far east
as 105W. Elsewhere, gentle winds are noted with seas 5 to 8 ft 
in NW swell.

For the forecast, very large NW swell impacting the Baja 
California offshore waters will bring seas of 12 to 17 ft today 
through Sun. Seas over 8 ft expanding across most of the 
southwest and southern Mexico offshore waters through the 
weekend. Conditions will begin to improve by early next week as 
seas are expected to subside Sun night into Tue night. The 
moderate NW winds over the Gulf of California will diminish to 
light to gentle later today.

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

Quiescent marine conditions dominate the waters with gentle to
moderate winds and seas of 4-6 ft in mixed swell. 

For the forecast, a building ridge north of the area will 
support fresh to strong NE gap winds over the Gulf of Papagayo 
region tonight through Tue night. Seas will build to 8 ft Sun 
through Mon night. Meanwhile, gale- force gap winds in the Gulf 
of Tehuantepec will cause NW swell with seas 7 to 9 ft over the 
Guatemala and El Salvador offshore waters tonight into Sun 
night. Fresh N winds will pulse at night in the Gulf of Panama 
from Sun night through Tue night. Otherwise, a weak pressure 
gradient will result in moderate or lighter winds across the rest
of the area through early next week. 

...REMAINDER OF THE AREA...

See the Special Features Section above for details on the very 
large NW swell across most of the forecast waters. 

The weak pressure gradient between a 1022 mb high at 25N122W and
the ITCZ is yielding moderate to fresh NE trades from the ITCZ 
to 22N and west of 115W. South of the ITCZ and monsoon trough, 
winds are moderate or less. Seas of 8 to 14 ft prevail across 
most of the area west of 104W and SE of a line from 20N105W to 
00N120W. To the NW of that line, seas are 12 to 20 ft. East of 
105W, seas are 5 to 7 ft.

For the forecast, see the Special Features section above for 
details on the very large swell over much of our forecast 
waters. Elsewhere, weak high pressure will dominate leading to 
generally moderate to fresh trades through Sat. High pressure is
expected to build across the northwest waters later in the 
weekend. This will enhance the NE trades between the ITCZ and
20N, and to the west of 127W from Sun through most of the week, 
bringing fresh to strong winds and 8 to 12 ft seas to the area. 

$$
AReinhart