000
AXPZ20 KNHC 231526
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1413 UTC Fri Dec 23 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 Tehuantepec: Winds to minimal gale force into the Gulf of
Tehuantepec will end later this morning as high pressure north of
the area weakens and overnight drainage effects cease. Northerly
winds of 20-30 kt are expected tonight into Saturday morning,
once again with the aid of the nocturnal drainage flow. Winds will
further diminish to 20-25 kt Saturday night into Sun morning.
Marine guidance suggests that winds will increase again to minimal
gale force Monday night into Tue morning as a ridge builds across
the western Gulf of Mexico.

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

The monsoon trough axis extends from 07N78W to 08N85W to 06N92W.
The intertropical convergence zone axis continues from 06N92W to
05N110W to 10N123W, then resumes west of a trough at 09N130W to
beyond 06N140W. Scattered moderate convection is from 09N to 12N
between 120W and 124W. Similar convection is within 30 nm of 07N134W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of California: A cold front approaching from the west will
bring an increase in winds across the north waters on Saturday.
Southerly winds in the 20-30 kt range are expected ahead of the
front in the northern Gulf of California with fresh to strong W-NW
winds in the wake of the front. The cold front will be moving
across northern Baja California and the Gulf of California,
including also forecast zones PMZ009, PMZ011, and PMZ013 Saturday
and Saturday night. NW winds of 20-25 kt and building seas of 10
to 14 ft in NW swell are expected in the wake of the front. The
highest of these seas are forecast to be confined to zone PMZ009,
and the northwest section of zone PMZ011 late on Saturday.

Currently, gentle to moderate NW-N winds are noted per
scatterometer data over the offshore waters W of Baja California
with seas of 8-10 ft in NW swell across much of the area W of
110W. On Saturday, expect increasing winds and building seas in
association with a cold front reaching the offshore waters.
  
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...

Fresh to strong gap winds pulsing through the Gulf of Papagayo
will diminish later this morning. The overall gradient is
weakening north of the area, but will allow brief pulses to 20 kt
over the next couple of nights. Winds will increase again to a
fresh to strong breeze across the Gulf of Papagayo Monday night
into Tuesday. Elsewhere across the region, winds will remain 20 kt
or less, with seas below 8 ft through early next week. Moderate
Northerly winds are expected across the Gulf of Panama during the
overnight and early morning hours.

REMAINDER OF THE AREA...

Long period northwest swell continues to impact much of the
waters N of 07N west of 110W with seas of 8 to 11 ft. Seas will
slightly subside today, but will build back across the northern
waters this evening as a cold front reaches the northern forecast
area. Fresh to strong northerly winds and a new set of large
northwest swell, with building seas up to about 14 ft along 30N,
will follow the front.

The most recent scatterometer data indicate an area of fresh to
strong trades from roughly 08N to 20N W of 135W, and from 08N TO
17N between 125W AND 135W. Seas of 8 to 11 ft, in mixed wind
wave and NW swell are noted within the area of the trade winds
based on altimeter passes. The strong high pressure that follows
the aforementioned cold front is forecast to move SE through
Saturday approaching the far NW corner of the forecast area. As
this high pressure builds in, the aerial extent of the trades will
increase again across the west-central waters. Another cold front
will move into the north waters Sunday night through Monday,
followed by strong northwest winds and 9 to 14 ft seas. Most of
the global models show the parent surface low related to this
front entering the forecast region by early Monday afternoon. The
main impact of this would be to tighten the pressure gradient
between the low pressure and the ridge to the northwest,
increasing northerly winds and seas over the north waters,
particularly N of 25N and west of 125W.

$$
GR