000
AXPZ20 KNHC 170841
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 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 0600 UTC surface analysis and satellite imagery through
0840 UTC.

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

The monsoon trough extends from 09.5N85W to 07N90W to 08N110W. 
The ITCZ continues from 08N110W to 09N115W. It resumes from 
08N121W to 10N130W, then from 08N136W to 07N140W. Scattered 
moderate convection is noted from 07N to 14N between 112W and 
120W, and from 08N to 10N between 120W and 130W. 

OFFSHORE WATERS WITHIN 250 NM OF MEXICO

Low pressure troughing stretches across northwestern mainland
Mexico while high pressure ridging dominates the waters north of
15N. The pressure gradient between the troughing and ridging is 
supporting fresh to strong winds west of Baja California Norte.
Moderate winds are noted west of Baja California Sur and the Gulf
of California. Fresh to strong gap winds prevail over the Gulf of
Tehuantepec. Light to gentle winds are elsewhere over the open
waters off Mexico. Seas are in the 8-9 ft range west of 110W and 
4-7 ft elsewhere over the open waters off Mexico. Seas of 4-5 ft
are over the southern Gulf of California and 1-3 ft over the
northern Gulf of California. 

For the forecast, NW swell west of around 110W will decay by the 
weekend. Fresh to strong winds west of Baja California will 
diminish by the end of the week. Fresh to strong winds will 
develop in the northern Gulf of California tonight through Sat. 
Fresh to strong N winds in the Gulf of Tehuantepec will diminish 
today, then return Sun afternoon, possibly increasing to gale- 
force Tue night.

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. Gentle to 
moderate winds will prevail elsewhere. No significant swell 
events are forecast through early next week. 

REMAINDER OF THE AREA...

High pressure ridging dominates the waters north of the ITCZ. Two
surface troughs are embedded in the ITCZ, the eastern one from
12N116W to 07N120W, and the western one from 11N131W to 07N135W.
The pressure gradient between the ridging and lower pressure in 
the vicinity of the ITCZ and within the troughs is supporting 
moderate to fresh trades north of the ITCZ to near 23N 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. Seas of 5-7 ft are noted elsewhere. A cold front has
moved into the northern waters extending from 30N125W to 29N134W.
This front has ushered in a set of reinforcing NW swell.  

For the forecast, winds across the open waters will gradually 
diminish during the first part of the weekend while another 
approaching front helps weaken the pressure gradient. The large 
NW to N swell will gradually decay through the weekend. The next
front is forecast to move southeast of 30N140W early Sun with 
moderate to fresh winds on either side of the front. The front 
will slowly progress east- southeast through early next week. The
front will usher in another set of NW swell, building seas to 
8-12 ft.

$$
AL