000
AXPZ20 KNHC 311508
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1452 UTC Mon Dec 31 2018

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.

.INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

A surface trough extends from 07N77W to 05N87W. The ITCZ 
continues from 05N87W to beyond 06.5N140W. Scattered moderate
isolated strong convection is noted from 05N to 07N between 104W
and 116W. Scattered moderate isolated strong convection is noted
from 05N to 08N W of 125W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

A surface ridge extending from the NE Pacific southeastward to 
near 18N108W is maintaining moderate NW to N winds across the 
offshore waters of Baja California. Northerly swell propagating 
into the waters off Baja California Norte will build seas to 
7-10 ft on Mon, and 5-7 ft offshore of Baja California Sur. Seas 
will then subside through Wed.

Gulf of California: A cold front will sweep southward across 
California and Baja California Norte Tue through late Wed. 
Associated strong high pressure behind the front will build from 
the Great Basin of United States southward across the region by 
midweek, supporting strengthening NWly winds over the Gulf of 
California Tue through Thu. Strong northerly winds will prevail 
across much of the Gulf by Tue night will spill through the 
mountain gaps of the Baja Peninsula to produce narrow zones of 
strong and gusty NE winds across the offshore Pacific waters of 
Baja California Tue night through late Wed night.

Gulf of Tehuantepec: Strong gap winds are expected to return to 
Tehuantepec late tonight through Tue night before diminishing 
Wed and Thu. Another cold front is expected to move across the 
western Gulf of Mexico Thu, allowing northerly winds to 
strengthen across Tehuantepec on Thu night, likely increasing to
gale force late Thu night through at least Fri. 

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

Fresh to strong NE to E winds are expected across and downstream
of the Gulf of Papagayo through Fri, peaking near 30 kt during 
the overnight and early morning hours. Moderate to fresh N winds 
are expected across the Gulf of Panama through Thu, pulsing to 
strong during the overnight hours. Elsewhere, gentle to moderate 
NE winds will prevail N of 08N, while gentle to moderate 
southerly winds are expected S of 08N.
  
REMAINDER OF THE AREA...  

High pressure of 1033 mb centered N of the area near 45N131W 
extends a ridge SE across the forecast waters to near 18N108W. 
The pressure gradient between this area of high pressure and 
lower pressure in the vicinity of the ITCZ is supporting a broad 
area of fresh to strong tradewinds N of the ITCZ to near 20N and
W of 110W. The area of high pressure will remain in place N of 
the area helping to maintain this broad area of fresh to strong 
trades. Long period NW swell is merging with this tradewind swell
to produce seas of 8 to 12 ft over much of the area north of the
ITCZ west of 120W. 

Global models continue to indicate a cold-core upper low will 
dig southward into the base of a mid/upper level trough between 
130W and 135W Tue through Fri. This will support the development
of a sharp surface trough or even weak low pressure along the 
ITCZ between 120W and 130W by mid week. The resultant tightened 
pressure gradient will enhance trade winds north of the ITCZ and
west of 120W, with near gale conditions possible north of the 
surface trough or low.

$$
AL