000
AXPZ20 KNHC 180337
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC SUN Dec 18 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 0000 UTC surface analysis and satellite imagery through
0230 UTC.

...SPECIAL FEATURES...

Gulf of California...A cold front has continued to move SE
across northwest Mexico and Baja California Norte this evening,
and had reached from 25.5N108.5W TO 24N110W, and across southern
portions of the Gulf of California. Winds following the front
remain around 20-25 kt N of 25N this evening, and 15-20 kt
elsewhere N of the front. Seas remain very rough north of the
Tiburon Basin, and are estimated at 5-7 ft. The front will
continue moving southeastward and through the entire gulf basin
by Sunday morning, with NW to N winds gradually diminishing to
15-20 kt with seas of 4 to 6 ft. Strong winds are expected to
increase again late Sunday afternoon as strong high pressure
builds northwest of the area. These winds will increase to 20-30
kt across north portions of the gulf Sunday night through early
Monday morning, and reach near gale force Monday morning through
afternoon across the far northern gulf with seas building 9-11
ft, before diminishing late Monday into Tuesday. Looking ahead,
this pattern will repeat again by late Tuesday through mid week.

Gulf of Tehuantepec...A cold front will move through the entire
western Gulf of Mexico Sunday and reach the western Bay of
Campeche by the evening hours. Cooler, drier air behind the
front will move across the isthmus of Tehuantepec into the Gulf
of Tehuantepec Sunday night, with winds reaching gale force
before 1200 UTC Monday. A large plume of gale force winds will
persist into early Wednesday across the Gulf of Tehuantepec,
with seas reaching as high as 18 ft by late Tuesday. Winds
diminish below gale force with subsiding seas through mid week
as the airmass to the north modifies and shifts east.
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...  

The monsoon trough extends from Colombia near 06N75W to 09N85W
to 07N89W. The ITCZ continues from 07N89W to 06N95W to 09N115W
to 07N130W to beyond 09N140W. Scattered moderate to strong
convection is noted within 90 nm N of the ITCZ between 118W and
122W. 

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gale warnings are in effect for the Gulf of Tehuantepec and
northern Gulf of California. See Special Features section above
for details.

Fresh to strong northerly winds follow a cold front extending
from 24N110W TO 22N120W TO 22.5N130W. These winds will spread
southward behind the front along the Pacific coast of Baja
California through this evening, with seas building to 5 to 8
ft. Winds and seas diminish through early Sunday as the front
continues to push S of the Gulf of California. 

Elsewhere offshore of Mexico, and outside of the Gulf of
Tehuantepec and Gulf of California, gentle to moderate breezes and
3 to 5 ft seas will persist.
     
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...

Fresh to strong northeast winds are expected to pulse across the
Gulf of Papagayo during the overnight and early morning hours
through Monday, with the assistance of the nocturnal drainage
flow. Seas should build 6-8 ft during the peak of each nights
wind. A larger gap wind event appears to be in store for most of
zone PMZ113 and southern portions of PMZ111 off El Salvador and
Guatemala Monday night into Tuesday morning, as strong trade
wind flow in the southwest Caribbean funnels across Central
America. Marine guidance indicates fresh to strong winds across
the Gulf of Fonseca and the Gulf of Papagayo will extend
westward to beyond 92W/93W by Tuesday morning, with seas
building up to 10-11 ft W of 90W. Moderate northerly winds are
expected across the Gulf of Panama at that time.

REMAINDER OF THE AREA...

Strong 1036 mb high pressure northwest of the area will shift SE
through Monday then stall N of 30N, which will produce a strong
pressure gradient to the south and southeast of the ridge, and
allow northeast winds to increase across much of the area north
of 10N through late Monday. Fresh to strong winds will cover the
area from 07N to 28N west of 120W early next week between the
high pressure to the north and a trough to the east. Seas will
reach 10-13 ft W of 130W in this area with the added component
of long period northwest swell. The winds will then diminish
through mid week as the high pressure weakens and the trough
dissipates. Seas of 8 to 9 ft will linger over much of the area
west of a line from Baja California Norte to 05N140W through
Tuesday.

A low level trough continues to move westward in a wave-like
fashion through the tropical eastern Pacific, located from
08N116.5W to 16N112.5W. Abundant tropical moisture continues to
shift west with this feature, and under favorable upper level
ridging, is producing scattered moderate to strong convection
within 120 nm W of the trough, and from 12.5N to 17.5N between
105W and 112W. This trough will aid in tightening the pressure
gradient to the southeast of the aforementioned ridge late Mon
through Wed.
  
$$
Stripling