000
AXPZ20 KNHC 190931
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Tue Dec 19 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 0600 UTC surface analysis and satellite imagery through 
0800 UTC.

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

The ITCZ extends from 06N96W to low pres near 07N113W to 08N126W 
TO beyond 10N140W. Scattered moderate isolated strong convection 
is noted from 08N to 13N between 122W and 140W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of California: Gentle to moderate NWly winds prevail across 
most of the gulf tonight and will change little through Wed. 
Northerly winds will increase abruptly 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, except 6-8 ft 
seas in the vicinity of las Islas Revillagigedo where NW swell 
prevails. 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 
mainly during the overnight and early morning hours with seas 
occasionally building to 8 ft the next couple of nights.

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 Fri. Fresh N winds over the Gulf of 
Panama are pulsing to around 20 kt tonight but will only 
increase to 15-20 kt Tue night.

Elsewhere, mainly gentle NE-E winds will prevail N of 09N, and 
moderate SW flow S of 09N.

REMAINDER OF THE AREA...

Northerly swell of 7-9 ft N of 20N continues to subside and will
be less than 8 ft over much of this area by early Wed. 

Mainly moderate winds prevail elsewhere 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.

$$
Stripling