000
AXPZ20 KNHC 302158
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2008 UTC Fri Dec 30 2016

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 1800 UTC surface analysis and satellite imagery through
2100 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning...The pressure gradient between
a high pressure ridge over eastern Mexico and lower pressure
within the monsoon trough over the eastern north Pacific is still
generating gale force winds as high as 40 kt over the Gulf of
Tehuantepec. The area of high pressure will shift rapidly over the
southwestern Atlantic waters Saturday morning, which will cause
the winds over the Gulf of Mexico to veer. This will decrease
winds funneling into the Gulf of Tehuantepec and bring an end to
the latest gale force gap wind event. Please see the latest
National Hurricane Center High Seas Forecast product under
AWIPS/WMO headers MIAHSFEP2/FZPN03 KNHC for further details.

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

The monsoon trough extends from 08N77W to 09N83W to 06N98W. The
ITCZ continues from 06N98W to 07N111W to beyond 08N140W.
Scattered moderate and isolated strong convection is noted from
01N to 04N between 78W and 80W and from 04N to 07N between 93W
and 95W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please see the special features section for details on the
continuing Gulf of Tehuantepec gale-force gap wind event. The
pressure gradient between the high pressure ridge west of the Baja
California peninsula and a surface trough over western Mexico
produced fresh to strong winds over the southern tip of Baja
California. The trough has begun to weaken and this trend will
continue through Saturday. This is loosening the pressure
gradient. Winds in this area have decreased to below 20 kt.
Residual NW swell in this area will subside and allow seas in this
area to fall below 8 ft on Saturday. A surface trough will shift
into the coastal waters off the coast of Baja California Norte
this weekend. This will strengthen winds over this area, as well
as the northern portion of the Gulf of California Saturday into
Sunday. The trough will shift east of the area Sunday. Winds will
decrease to 20 kt or less by late Sunday. This trough will usher
in a round of NW swell on Saturday. The swell will cause seas off
the coast of Baja California Norte N of 25N to build to between 8
and 11 ft Saturday. The swell will begin to subside on Sunday.
This will allow combined seas to drop below 8 ft by midday on
Monday.
  
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...

Fresh to strong winds will pulse at night over the Gulf of
Papagayo tonight and Saturday. Peak winds will occur during the
overnight hours as the gap winds are enhanced by nocturnally
induced drainage flow. Winds will decrease to 20 kt or less by
Saturday evening. Elsewhere, winds will remain 20 kt or less, with
seas below 8 ft through the end of the week.

REMAINDER OF THE AREA...

Northwesterly swell continue to subside over the forecast waters.
Seas associated with these swell will fall below 8 ft Saturday.
Trades north of the ITCZ are expected to remain below 20 kt during
the next several days, but mixed trade-wind waves and NW swell
will maintain sea heights just above 8 ft from 07N to 10N between
106W and 111W. Seas in this area will decrease to below 8 ft by
Monday. A fresh set of NW swell has propagated into the NW waters.
Seas associated with these swell are peaking at 10 ft near 30N140W
as the swell begin to decay. Seas in this area will subside below
8 ft by Saturday evening.

$$
cam