000
AXPZ20 KNHC 301503
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1333 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 1200 UTC surface analysis and satellite imagery through
1500 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 continue
to support gale force winds up to 40 kt over the Gulf of
Tehuantepec. The area of high pressure will then shift rapidly
into 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 which will
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 09N85W to 05.5N92W to 05.5N95W. The
ITCZ extends from 05.5N95W to 09N127W to beyond 10N140W. Scattered
moderate isolated strong convection was noted within 90 nm north
of the monsoon trough between 92W 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
is supporting fresh to strong winds over the southern tip of Baja
California. The trough will weaken tonight into Saturday. This
will help loosen the pressure gradient, with resulting winds
decreasing to 20 kt or less late tonight. 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 and
winds will decrease to 20 kt or less late Sunday. This trough will
usher in a set of northwesterly swell Saturday with seas building
to near 10 ft off the coast of Baja California Saturday. The swell
will subside through the weekend, falling below 8 ft by 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 through 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 during the
late afternoon and early evening hours. 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 continues to subside over the forecast
waters. Seas associated with these swell will subside below 8 ft
Saturday. Trades north of the ITCZ are expected to remain below 20
kt during the next several days. A fresh set of NW swell has
propagated into the northwest waters. Seas associated with these
swell will peak near 10 ft this afternoon, then subside below 8 ft
by Saturday evening.

$$
AL