000
AXPZ20 KNHC 291425
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1530 UTC Fri Dec 29 2017

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
high pressure over eastern Mexico and a surface trough over the
eastern North Pacific is supporting gale force winds over the
Gulf of Tehuantepec. The area of high pressure will weaken and
shift eastward tonight into Saturday. This will loosen the 
pressure gradient and diminish winds below gale force Saturday. 
In addition, winds north of the area will veer Saturday which 
will further diminish winds funneling into the Gulf of 
Tehuantepec. By Sunday, winds will diminish to 20 kt or less, 
bringing an end to this latest Gulf of Tehuantepec gap wind 
event. Refer to the latest high seas forecast issued under 
AWIPS/WMO headers HSFEP2/FZPN03 for more details.

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

A surface trough extends from 08.5N78W to 06N95W, where it 
transitions to the intertropical convergence zone and continues 
to 08N125W. It resumes from 09N130W to beyond 09N140W. No
significant convection is noted. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of Tehuantepec: Please refer to the special features 
section above for details on an ongoing Gulf of Tehuantepec Gale 
event. Looking ahead, A cold front will push into the Gulf of
Mexico on Sunday. The front will reach the Bay of Campeche
Monday, and will bring the next gale force gap wind event into
the Gulf of Tehuantepec, possibly as a strong gale.

Elsewhere, tranquil marine conditions are expected with light to
gentle winds prevailing over the forecast waters. Seas in the 
range of 3-5 ft will prevail over the offshore waters, while seas
in the 1-3 ft range will prevail in the Gulf of California.

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

Nocturnal winds will pulse to fresh to strong over the Gulf of 
Papagayo through mid week. Light to gentle winds will prevail 
elsewhere N of 09N with gentle to moderate winds prevailing S of 
09N.

REMAINDER OF THE AREA...

Low pressure along the intertropical convergence dissipated a few
hours ago as it move farther west and beyond the area of upper
support. A broad surface trough remains in its place from 10N to
15N between 125W and 130W. An earlier scatterometer pass
indicated trade winds have diminished on the north end of the
trough, but a concurrent altimeter pass showed lingering seas to
9 ft, likely due to a component of long period NW swell.
Elsewhere broad ridging dominates the waters north of 20N with
gentle to moderate trades farther south, and seas 5 to 7 ft
throughout the region. Little change is expected through Sunday.  
Looking ahead, deepening low pressure will approach the northwest 
portion of the forecast area Sunday. The pressure gradient 
between this deepening low and high pressure west of the area 
will bring strong to near gale force winds north of 25N and west 
of 130W, with the possibility for winds to reach minimal gale 
force over this area Monday. 

$$
Christensen