000
AXPZ20 KNHC 240312
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Sat Dec 24 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 0000 UTC surface analysis and satellite imagery through
0300 UTC.

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

The monsoon trough axis extends from 09N84W to 06N94W. The
intertropical convergence zone axis extends from 06N94W to
05N105W to 07N111W to 07N24W to 08N130W to beyond 06N140W.
Scattered moderate convection isolated strong convection
is noted within 120 north of the axis between 128W and 134W.

A weak surface trough is along a position from 13N132W to
10N135W with scattered moderate convection within 60 nm either
side of the trough from 10N to 12N.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of Tehuantepec: North to northeast winds are occurring
across 45 nm swath that extends from 16N95W to 14.5N95.5W with
associated seas in the range of 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 Saturday
morning, and to 15-20 kt later during Saturday afternoon with
seas subsiding to 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.

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. These seas over the northern portion will build higher
tonight into Saturday as a strong cold front extending from
32N124W to 28N131W to 28N140W sweeps across the those waters.
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 in behind the front.

Ascat data from Friday afternoon showed an area of fresh to
strong trades from roughly 08N to 20N W of 135W with seas of 8
to 11 ft as noted from 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 coverage of
these 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 a significant
tightening of the pressure gradient between the low pressure and
strong high pressure to its northwest that is expected to lead
to increasing northerly winds and seas over much of the northern
waters, mainly N of 25N and west of 125W.

$$
Aguirre