000
AXPZ20 KNHC 171519
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Sun Dec 17 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: The pressure gradient between
high pressure along the eastern slopes of Mexico and the eastern
north Pacific monsoon trough is supporting gale- force north to 
northeast winds of 30-40 kt in the Gulf of Tehuantepec, with 
seas in the 9-13 ft range. A tight pressure gradient will support
gale conditions through much of the week. Seas with this latest 
gale force gap wind event are forecast to peak near 14 ft on Tue.

Eastern Pacific Gale Warning and Significant Swell event: A deep
extratropical low pressure system is located north of the area 
near 34N136W with pressure of 990 mb. A stationary front out 
ahead of this low pressure system stretches southward to 30N126W 
to 22N129W and to 15N137W. Gale-force southwest winds are north 
of 29N and between 132W-134W, with seas peaking in this area near
19 ft. These winds will lift north of 30N by this afternoon as 
the low tracks to the northeast. A large area of seas greater 
than 12 ft generated from this system covers much of the waters N
of 17N and W of 127W. These seas will start to subside today,
decreasing below 12 ft on Mon. Seas of 8 ft or greater with this
swell cover much of the waters N of 09N and W of 123W. Seas
greater than 8 ft will spread SE, covering much of the waters 
west of 120W on Mon before starting to gradually subside.

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

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

The monsoon trough extends from 09N83W to 05.5N97W. The ITCZ
continues from 05.5N97W to 07N140W. Scattered moderate convection
is noted from 03N to 09N between 83W and 89W, and within 60 nm of
the ITCZ between 102W and 135W. 

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

Please see the Special Features section for details on an 
ongoing Gulf of Tehuantepec Gale Warning.

Fresh northwest winds are over the Gulf of California. A weak 
pressure gradient dominates the Mexican offshore waters outside 
of the Gulf of Tehuantepec. Moderate or weaker winds and slight 
to moderate seas prevail across the rest of the offshore waters.
Seas across the Baja California offshore waters and over the 
southern Mexico offshore waters are in the 4-6 ft range in long-
period west to northwest swell.

For the forecast, the fresh northwest winds over the central and
southern sections of the Gulf of California will gradually 
diminish through the week. Seas to around 8 ft associated from a 
large swell event will reach the outer offshore forecast waters 
of Baja California between Cabo San Lazaro and Punta Eugenia 
tonight, then subside on Tue. 

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

Moderate to fresh northeast to east winds, and seas of 3-5 ft,  
are in the Gulf of Papagayo region. Seas of 6-9 ft in a 
northwest swell generated by the Gulf of Tehuantepec gap wind 
event are over the outer offshore waters of Guatemala and El 
Salvador. Gentle north winds and seas of 3-4 ft are in the Gulf 
of Panama.

For the forecast, winds in the Gulf of Papagayo will increase to
fresh to strong early this week, and continue through the week. 
These winds are expected to reach near gale force Mon night 
through Wed. Rough seas are expected over the Guatemala and El 
Salvador offshore waters today due to the Gulf of Tehuantepec gap
wind event. Fresh north winds are expected over the Gulf of 
Panama starting tonight and continuing well into the upcoming 
week. These winds will be fresh to strong Tue night through Wed 
night. Elsewhere, winds are expected to be moderate or weaker for
the next several days.

...REMAINDER OF THE AREA...

Please see above for details on the Gale Warning and significant
swell event for the western portion of the basin.

A 990 mb low pressure system is centered N of the area near 
34N136W. A stationary front out ahead of this low pressure 
system stretches southward to 30N126W to 22N129W and to 15N137W. 
A tight pressure gradient between this deep low and high pressure
centered to its east will remain in place over the northwest 
corner of the forecast area today. Elsewhere, gentle to moderate
winds are on either side of the ITCZ/Monsoon Trough with seas of
5-7 ft in mixed swell.

For the forecast, gale force winds over a portion of the
northwest forecast waters will lift northeast of the area 
this morning as the low tracks to the northeast. The trade winds
north of the ITCZ to will increase slightly to fresh speeds 
today. Winds south of the ITCZ will be in the moderate to fresh 
range through Mon. Swell from the Tehuantepec gap wind event 
will spread westward, with seas of 8-9 ft reaching to near 104W
tonight before starting to subside. 

$$
AL