000
AXPZ20 KNHC 160752
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
652 UTC Fri Dec 16 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 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec...A Gale Warning is in effect for the Gulf
of Tehuantepec through late Friday morning. An ASCAT pass from 04
UTC indicated 20 to 30 kt winds were ongoing, and this will likely
increase to minimal gale force later in the morning, with seas
building to 9 to 11 ft. Winds will then diminish gradually
throughout the early afternoon, reach around 20 kt only across
the immediate Gulf of Tehuantepec this evening, and then less than
15 kt by Saturday morning. A stronger cold front over the weekend
could produce a more significant northerly gale wind event
beginning on Monday.

Gulf of California...A cold front approaching the region from the
west is forecast to reach northern Baja California this evening
and move eastward across the region, including the northern part
of the Gulf of California by tonight. Expect strong westerly gap
winds north of 29N winds over the far northern Gulf by this
evening ahead of the front, then veering to the northwest and
briefly increasing to minimal gale force tonight as the front
moves east of the area. Strong northwest to north winds will then
spread southward across the Gulf of California Sat and Sat night
as the front moves southeastward through the region.
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...  

The monsoon trough extends from 09N85W to 06N92W to 1012 mb low
pressure 09N107W. The ITCZ continues from 09N107W to 07N120W to
09N130W to beyond 08N140W. Scattered moderate convection is
noted within 120 nm either side of the axis between 100W and
105W, and within 90 nm n of the ITCZ between 128W and 132W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

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

Gentle to moderate northerly winds and seas of 3-4 ft continue
over the offshore waters west of Baja California this morning,
under the influence of a weakening ridge extending southward from
a 1019 mb high pressure centered near 24N122W. The high pressure
dissipates today ahead of a cold front expected to move across the
region from west to east through Saturday. This will bring strong
northwest flow to the waters off Baja California Norte by early
Saturday with 8 to 10 ft behind the front, with fresh northwest
winds and 5 to 8 ft seas off Baja California Sur. These winds and
seas will diminish late Saturday through Sunday as high pressure
builds eastward behind the front. Elsewhere off Mexico 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 across the Gulf of
Papagayo during the overnight and early morning hours with the
assistance of the nocturnal drainage flow during the next 48
hours. 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 Tuesday morning as strong trade wind flow in the
southwest Caribbean funnels across Central America.

REMAINDER OF THE AREA...

A cold front reaches from 30N130W to 27N136W then is stationary to
26N140W. The cold front will continue to move east across the
waters north of 25N through Saturday. This will keep the
subtropical ridge fairly weak and in turn result in only moderate
trade wind flow farther south in the deep tropics. The trade winds
will increase across the region north of 07N through late Saturday
as strong high pressure builds north of the area behind the front.
20 to 25 kt trade winds are anticipated from 09N to 16N west of
135W by late Saturday/early Sunday. 

Farther east, a weak 1012 mb surface low is centered along the
monsoon trough near 09N107W, with a surface trough reaching north
to 16N104W. Fresh east winds are noted in 04 UTC ASCAT pass over
the low pressure. Scattered showers and thunderstorms are also
noted near the low pressure along the monsoon trough. The low will
dissipate through Saturday as it drifts west along the monsoon
trough/ITCZ, with the trough persisting a couple of more days,
reaching near 120W by early next week. While the low pressure and
trough will have little impact on winds and seas in their vicinity
as they weaken further, scattered showers and a few thunderstorm
are likely with 120 nm through at least Saturday.
  
$$
CHRISTENSEN