000
AXPZ20 KNHC 240250 CCA
TWDEP 

Tropical Weather Discussion...corrected
NWS National Hurricane Center Miami FL
2205 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 1800 UTC surface analysis and satellite imagery through
2145 UTC.

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

The monsoon trough axis extends from 07N78W to 08N85W to 07N90W.
The intertropical convergence zone axis extends from 07N90W to
05N100W to 06N110W to 08N119W to 09N125W...then resumes at
08N135W to beyond 06N140W. Scattered moderate convection is
noted within 120 north of the axis between 119W and 122W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of Tehuantepec: The earlier observed northerly gale force
winds have diminished to just below gale force this afternoon,
with winds in the range of 20-30 kt with the aid of nocturnal
drainage flow. Seas with these winds are in the 8-10 ft. As the 
pressure gradient between high pressure over eastern Mexico and 
relatively lower pressures over southeastern Mexico and the far
eastern Pacific continues to slacken, these winds will continue
to further diminish reaching a range of 20-25 kt early on
Saturday afternoon, and to 15-20 kt later during Saturday
afternoon with seas less than 8 ft. Northerly winds briefly
pulse to 20-25 kt early on Sunday before diminishing to 15-20 kt
in Sunday afternoon with seas less than 8 ft. Model guidance
suggests that winds will increase again to minimal gale force
Monday night into Tuesday morning as high pressure builds across
the western Gulf 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 to 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 mixed northeast and 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.

Ascat data from this afternoon showed 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.

$$
Aguirre