000
AXPZ20 KNHC 172119
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Fri Dec 17 2021

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 1800 UTC surface analysis and satellite imagery through
2100 UTC.

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

The monsoon trough extends from 10N84W to 07N98W. The ITCZ 
continues from 07N98W to 09N115W to beyond 08N140W. Scattered 
moderate convection is noted from 07N to 10N W of 125W. 

OFFSHORE WATERS WITHIN 250 NM OF MEXICO

A dissipating cold front crosses the northern Gulf of California
and northern Baja California, then continues across the northern
forecast waters to 28N120W to 27N130. Seas of 8-10 ft follow the
front. A ridge dominates the remainder of the offshore forecast 
waters on Baja California producing mainly a gentle NW to N flow.
Gentle to moderate northerly winds are noted per scatterometer 
data inside the Gulf of California. Winds have diminished below 
20 kt in the Gulf of Tehuantepec while mainly fresh NE winds are 
noted in the Gulf of Papagayo based on recent satellite derived 
wind data. Light to gentle winds are elsewhere over the open 
waters off Mexico. Seas are in the 6-8 ft range N of 20N and W of
110W and 4-7 ft elsewhere over the open waters off Mexico. Seas 
of 2-4 ft are in the Gulf of California. 

For the forecast, NW swell will continue to dominate the offshore
forecast waters of Baja California with seas of up to 8 ft. This
swell event will gradually decay during the upcoming weekend.  
Fresh to strong winds will develop in the north and central parts
of the Gulf of California tonight through Sat. A new gap wind
event is expected in the Tehuantepec region beginning on Sun
night, with gale conditions possible on Tue. Seas are forecast 
to build to 10-12 ft with the strongest winds. 

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

Fresh to strong NE winds prevail across the Papagayo region.
Light to gentle winds are noted elsewhere north of the monsoon
trough. Gentle to moderate S to SW winds prevail south of the
monsoon trough. Seas of 3 to 5 ft in mixed swell dominate the 
offshore waters.

For the forecast, NE to E winds will pulse to fresh to strong in
the Papagayo region through the next several days, particularly
during the overnight and early morning hours. Gentle to moderate
winds will prevail elsewhere. No significant swell events are 
forecast through early next week.

REMAINDER OF THE AREA...

A ridge dominates the waters north of the ITCZ. Two surface 
troughs are embedded within the ITCZ, the eastern one extends 
from 11N122W to 06N125W, and the western one runs from 11N135W 
to 08N139W. The pressure gradient between the ridge and lower 
pressure in the vicinity of the ITCZ and within the troughs is 
supporting fresh to locally strong trade winds north of the ITCZ 
to near 21N and west of 120W. Gentle to moderate winds prevail 
elsewhere. NW to N swell is dominating the waters west of 110W, 
producing seas of 8-11 ft per recent altimeter passes. Seas of 
5-7 ft are noted elsewhere. The aforementioned dissipating cold 
front has ushered in a set of reinforcing NW swell with seas up
to 12 ft near 30N130W.

For the forecast, an area of fresh to locally strong trade winds
will persist across the west-central waters on Sat. The large NW
to N swell will gradually decay through the weekend. The next 
cold front is forecast to move southeast of 30N140W early Sun 
with fresh to locally strong winds on either side of the front. 
The front will slowly progress east-southeast through early next
week. The front will bring another NW swell event, building seas
to 8-12 ft.

$$
GR