000
AXPZ20 KNHC 181601
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1401 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.

...SPECIAL FEATURES...

Gulf of California...Moderate to fresh northwest winds continue to
move down the length of the Gulf of California this morning. The
winds were following a weakening cold front that has since
dissipated over the southern Gulf. The winds will increase
substantially over the northern Gulf starting tonight as strong
high pressure ridges southward over the Great Basin. Winds will be
near minimal gale force early Monday morning, with seas building
to 11 ft north of Tiburon Island. Winds and seas will then
diminish through early Tuesday as the high weakens and shifts
east, leaving areas of 20 to 25 kt winds across the Gulf. This
pattern repeats again starting late Wednesday with strong to near
gale force winds pushing across the Gulf through early Thursday.

Gulf of Tehuantepec...A cold front has entered the western Gulf
of Mexico. It will reach the southwest Gulf of Mexico by this
evening. Cooler, drier air behind the front will move across the
isthmus of Tehuantepec into the Gulf of Tehuantepec tonight, with
winds reaching gale force around 0600 UTC on Monday. A large
plume of gale force winds, possibly reaching near storm force by
Tuesday, will persist into early Wednesday across the Gulf of
Tehuantepec. Seas may reach as high as 19 ft by Tuesday morning given
the strength and extent of the gales. Winds diminish below gale
force with subsiding seas through mid week as the air mass to the
north modifies and shifts east. Looking ahead, there is some
disagreement among major models concerning the strength of another
gale event later in the week. Given this uncertainty, the official
forecast for Thursday night and Friday carries winds just below
gale force but another gale warning may be required in conjunction
with this event.
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...  

The monsoon trough extends from 09N77W to 09N89W. The ITCZ
continues from 09N89W to 09N98W to 08N104W to 10N111W to 10N116W.
The ITCZ resumes from 08N122W to 05N132W to 07N135W to beyond
08N140W. Scattered moderate and isolated strong convection is
found within 90 nm either side of a line from 10N115W to 07N124W.

...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.

Moderate to fresh northerly flow persists over the waters off
Baja California today, with 5 to 7 ft seas. The winds will
diminish today across the region. A small plume of fresh to strong
gap winds will emerge W of the peninsula and cross Sebastian
Vizcaino Bay late tonight and early Monday. Similarly another gap
wind plume with fresh to locally strong winds will emerge off Baja
California Sur near Todos Santos Tuesday with seas building to 7
ft offshore. These winds will diminish by late Wednesday.

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 and coast of Nicaragua during the overnight and
early morning hours through Monday, with the assistance of the
nocturnal drainage flow. Seas should build to 6-8 ft when winds
peak. 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 as far west as 97W
by Tuesday morning, with seas building to 10-11 ft west of 90W.
Moderate to fresh north winds are expected across the Gulf of
Panama at that time.

REMAINDER OF THE AREA...

Strong high pressure north of the area will support a broad area
of fresh to strong northeast to east winds over much of the region
north of 07N and west of 120W by Monday. Farther east, an upper
level trough to the west of Baja California will become cut off
near 24N124W by early on Tuesday. The upper level trough has been
inducing a surface trough that currently reaches from 07N120W to
13N116W to 16N112W. The trough will become more amplified and low
pressure could consolidate within it as it drifts northwest into
the ridge through the next couple of days. The tighter pressure
gradient on the N side of this system will enhance the area of
northeast winds Monday through mid week. Seas will build to
between 12 and 13 ft from 13N to 25N west of 125W by Monday
afternoon as longer period NW swell mix with shorter period NE
swell.
  
$$
cam