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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 051558
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Sat Dec 5 2020

Tropical Weather Discussion for the eastern Pacific Ocean from
the Equator to 32N, east of 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: A ridge across the eastern 
slopes of the Sierra Madre Mountains will support fresh to 
strong northerly winds, with frequent gusts to gale force over 
the Gulf of Tehuantepec this morning. Winds will further diminish
this afternoon, and then remain below gale force through much of
the weekend. A cold front will enter the Gulf of Mexico tonight,
and shift across the Gulf of Mexico through early next week. 
High pressure will build in the wake of the front, and support 
another round of gale force gap winds in the Gulf of Tehuantepec 
late Sun night through Wed night. This will be a stronger gap 
wind event with winds in excess of 40 kt late Mon into early 
Tue. Seas will build to 14-16 ft during this period of strongest 
winds. Please read the latest NWS High Seas Forecast issued by 
the National Hurricane Center at website 
https://www.nhc.noaa.gov/text/MIAHSFEP2.html for more details.

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

The monsoon trough extends from 08N77W to 1010 mb low pressure 
near 09N93W to 07N105W to 1010 low pressure near 10N118W to 
08N130W. The ITCZ continues from 08N130W to beyond 07N140W. 
Scattered moderate isolated strong convection is noted from 08N 
to 14N between 118W and 126W, from 06N to 09N between 126W and 
134W, and from 15N to 18N between 109W and 113W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

Please see the Special Features section for more on the Gulf of 
Tehuantepec gale force gap wind event.

Elsewhere, moderate to locally fresh NW-N winds prevail over the
Gulf of California, with seas in the in the 2-4 ft range. NW 
swell continues across the offshore waters off Baja California 
with sea heights of 8-10 ft. Seas over this area will subside 
through the weekend, falling below 8 ft late on Sunday. Another 
set of NW swell will enter the waters off Baja California early 
next week. Seas will peak near 14 to 15 ft off Baja California 
Norte by Tue.

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

Gulf of Papagayo: Mainly fresh NE to E winds are expected in the
Gulf of Papagayo at night through Mon. Then, fresh to strong 
winds are expected in the Papagayo region Mon night through Wed 
night as high pressure builds over the western Caribbean. 

Elsewhwere, light to gentle winds are expected north of the 
monsoon trough, with gentle to moderate S to SW winds south of 
the monsoon trough, through the upcoming weekend. Swell from the 
upcoming gale force gap wind event in the Gulf of Tehuantepec 
will build seas to 8-9 ft over the waters off Guatemala and El 
Salvador early next week. Seas in the 4-5 ft range will prevail 
elsewhere.

REMAINDER OF THE AREA...

High pressure of 1026 mb is centered near 32N127W. The pressure 
gradient between this area of high pressure and lower pressure in
the vicinity of the ITCZ, and within the monsoon trough, is 
supporting moderate to fresh trade winds roughly from 10N to 20N 
west of 120W. Seas are 8 to 10 ft in NW swell across this area. A
ridge will persist across the northern forecast waters over the 
next several days, keeping a large area of fresh trade winds.

Large, long period, NW swell continues to propagate across most 
of the waters N of the equator and W of 120W. Seas associated 
with this swell have started to subside and will continue to 
slowly subside through the weekend. Another large NW swell event 
will reach the NW corner of the forecast area by Sat. This swell 
will bring seas greater than 12 ft, over much of the waters 
north of 20N on Tue. Seas will peak near 15-17 ft Tue before
starting to subside. Seas greater than 8 ft with this swell will
propagate SE across the area, covering much of the waters west of
105W by Wed night.  

$$
GR