AXPZ20 KNHC 051558
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
Based on 1200 UTC surface analysis and satellite imagery through
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
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.