000
AXPZ20 KNHC 190908
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
908 UTC Mon Dec 19 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 California...A tight pressure gradient between strong
high pressure centered over the Great Basin north of the area and
lower pressure over west central Mexico will allow winds to reach
gale force this morning over the far northern Gulf of California.
Seas will build as high as 12 ft today between the mouth of the
Colorado River and Tiburon Island. Winds over the far northern
Gulf will diminish below gale force later today as the high
pressure shifts east. But fresh to strong northwest winds will
persist across much of the Gulf of California into Wednesday
before diminishing by late Wednesday. Seas will reach 8 ft between
Los Cabos and Cabo Corrientes by Thursday due in part to northerly
swell from the Gulf of California. 

Gulf of Tehuantepec...Cooler, drier air is spilling into the Gulf
of Tehuantepec behind a cold front, with winds likely reaching
gale force. A large plume of gale force winds will persist into
early Wednesday across the Gulf of Tehuantepec. Most model
guidance indicates this will be a relatively strong gale,
approaching storm force by Tuesday. Given the pattern north of
the area showing fairly cold air and strong high pressure through
Texas into northeast Mexico and the western Gulf of Mexico, this
seems plausible. Winds very gradually diminish below gale force
with subsiding seas by Thursday as the air mass to the north
modifies and shifts east. After a brief hiatus on Thursday, the
next cold front moving across the Gulf of Mexico is likely to
reinforce the Tehuantepec event on Friday and Saturday. There is
growing consensus among global models winds will again reach gale
force behind the next front, and this has been incorporated into
the forecast accordingly.
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...  

There are segments of the ITCZ from 07N97W to 10N118W, and from
10N123W to 07N140W. No significant monsoon trough is observed in a
very light wind flow, but there is weak troughing from the coast
of Colombia near 05N78W to 07N97W. A weak surface trough is
analyzed from 08N121W to 15N118W, related to an upper trough is
the same area. Scattered moderate showers and thunderstorms are
noted within an area bounded by 09N125W to 15N120W to 15N110W to
09N119W to 09N125W.

...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 4 to 6 ft, reaching 7 ft beyond 200 nm.
A small plume of fresh to strong gap 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 from the
Gulf of Papagayo to the Gulf of Fonseca during the overnight and
early morning hours through Wednesday morning, with the assistance
of the nocturnal drainage flow. Seas should build to building to
10 ft west of 90W. Northeast swell will merge with the Gulf of
Tehuantepec gap wind event to provide a large area of 8-12 ft
seas from 10N to 13N to 110W late Tuesday and to 117W on late
Wednesday. The gap winds should diminish by late Wednesday and
generally remain 20 kt or the rest of the week. Northerly moderate
to fresh breezes will pulse across the Gulf of Panama through the
end of the week.

REMAINDER OF THE AREA...

A 1035 mb high pressure is centered north of the area at 37N135W
west of California, supporting a broad area of fresh to strong
northeast to east winds over much of the region north of 07N and
west of 120W. Farther east, an upper level trough to the west of
Baja California will become cut off near 24N124W early on Tuesday.
The upper level trough has been inducing a surface trough that
currently reaches from 08N121W to 15N118W. 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 north side of this system
will enhance the area of northeast winds through mid week. Seas
will build to about 12 ft from 13N to 25N west of 125W by this
afternoon as longer period northwest swell mixes with shorter
period northeast swell.
  
$$
CHRISTENSEN