000
AXPZ20 KNHC 200304
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
035 UTC Wed Dec 20 2017

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 ITCZ extends from 07N94W to 09N115W to 09N126W to 08N132W to
beyond 10N140W. There is no significant convection.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of California: Northerly winds will increase abruptly to 
strong to near gale force behind the next cold front expected to
move through most of the basin early Thu through Fri. Seas will 
build quickly to 6-9 ft by late Thu. These strong winds are also 
forecast to seep through Baja California mountain passages and 
into the open Pacific waters W of the peninsula.

Elsewhere across the offshore waters of Mexico, gentle to 
moderate mainly NW winds prevail with 4-7 ft seas. A fresh pulse
of NW swell will propagate into the waters off the coast of Baja
California Norte Thu behind the next cold front, with seas 
building briefly 8-10 ft across the far northern waters, then 
fading to 6-9 ft early Fri.

Gulf of Tehuantepec: Northerly winds will pulse fresh to strong 
tonight before diminishing. Looking ahead...gale force winds will
be possible over the gulf Sunday night as a strong cold front
moves across the Gulf of Mexico, and winds funnel through the
Chivela pass into the Gulf of Tehuantepec. 

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...

Fresh to strong NE winds will pulse mainly at night offshore of 
Gulf of Papagayo through Wed. Elsewhere gentle to moderate NE-E 
winds will prevail N of 08N, while gentle SW flow will prevail S 
of 08N. 

REMAINDER OF THE AREA...

Gentle to moderate winds prevail over the forecast waters N of 
the ITCZ to 20N and W of 112W. High pressure across the NE 
Pacific will dominate the regional waters for the next few days 
with little change in winds.

Looking ahead, the pressure gradient will increase N of 20N and W
of 130W between the high and low pressure moving northward W of
140W. SE flow around the high will increase to fresh to strong 
with seas building to 7-9 ft Thu night. The low may then briefly
cross to near 30N140W by late Fri night. The gradient may
continue to tighten and if so, gale conditions may be possible 
in the NW corner with seas building to well over 12 ft.

$$
AL