000
AXPZ20 KNHC 190320
TWDEP 

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

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

A discontinuous ITCZ axis extends from 04N89W to 03N104W to 
08N123W to 06N140W. Scattered moderate convection from 08N to 
10N between 125W and 134W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Satellite water vapor imagery shows a large moisture plume of 
mid and upper level clouds advecting northeastward towards much 
of central Mexico. Jet stream energy is combining with the deep 
moisture to produce widespread offshore showers from south of 
Manzanillo northward to Mazatlan. The upper trough will slide 
eastward through Friday and shear out. A stronger trough will 
sweep southeastward and merge into the first trough Thursday, 
with associated moisture and weather shifting eastward with it.

Scatterometer data shows gentle to moderate northwest to north 
winds west of Baja California and in the Gulf of California. 
Light to gentle northerly winds prevail south and east of 
Acapulco. Seas in the area are 5-6 ft west of Baja California, 1 
to 3 ft in the Gulf of California, and 3-5 ft elsewhere. 

Global models indicate a cold front will move into the waters 
off Baja California Norte Thursday, then become diffuse ahead of 
a much stronger cold front that will quickly move in across Baja 
California and the Gulf of California Friday and Saturday. The 
second cold front will be accompanied by fresh to strong winds 
and large northwest swell. This swell event is expected to build 
seas to 12-19 ft off Baja California Norte Saturday, and 8-13 ft 
seas off Baja California Sur. Wave model guidance indicates max 
seas may be around 21 ft in the waters north of 29N on Saturday. 
These marine conditions are likely to bring hazardous marine 
conditions to mariners navigating the near shore and coastal 
waters, and very dangerous surf conditions along the coast. 
Southwest winds ahead of the second cold front are expected to 
increase to near gale force over much of the northern Gulf of 
California late Friday nigh, with seas building to 8-9 ft.
  
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...

Northeast winds will pulse over 20 kt late tonight across the 
Gulf of Papagayo and downwind to about 88W. Winds will diminish 
Thursday night, becoming light to gentle variable winds Friday.

Light to gentle easterly winds will prevail elsewhere through 
Saturday. Seas will be generally 3-5 ft in the forecast waters.

REMAINDER OF THE AREA...

A ridge extends eastward from 25N140W to the Baja peninsula. The 
gradient between the ridge and low pressure associated with the 
ITCZ is supporting an area of fresh to strong northeast trade 
winds from 08N to 13N west of 130W in 9-10 ft seas. ASCAT data 
shows fresh trades elsewhere, from 07N to 20N west of 115W. Seas 
with the trades are 7-10 ft in northwest swell and northeast 
wind waves. The ridge will be nudged southwest over the next two 
days as the aforementioned cold fronts sweep across the waters 
north of 25N. This will allow the trades to decrease in coverage 
and shift westward through Friday.  

Looking ahead, northwest swell with seas to 8-16 ft associated 
with a cold front moving eastward across the waters north of 25N 
Thursday will be followed by a second front expected to sweep 
southeastward across the northern waters Thursday night and 
Friday. Wave model guidance shows large northwest swell will 
propagate southeastward into the waters north of 20N behind the 
second front, with seas building quite large to 15-21 ft in the 
far northern waters east of 130W late Friday into Saturday. 

$$
Mundell