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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 221545
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL
1605 UTC Tue May 22 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 
1545 UTC.  

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

The monsoon trough extends west from the Pacific coast of 
Colombia at 09N78W across the northern Gulf of Panama and then 
across Panama and southern Costa Rica continuing almost due west 
to 07N127W where scatterometer winds indicate a transition to an 
ITCZ which continues to 09N133W, then turns southwest to beyond 
06N140W. Scattered moderate isolated strong convection is noted 
within an area bounded by a line from 15N100W to 12N87W to 
03N79W to 05N101W, and within 180 nm either side of a line from 
07N109W to 10N126W to 08N140W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A northwest to southeast ridge will meander beyond 250 nm 
seaward of northern and central Mexico for the next few days. 
Moderate northwest flow is observed west of 100W, and light to 
gentle northwest flow is observed east of 100W.  An area of 6 to 
8 ft seas currently noted east of 115W will subside to 4 to 7 ft 
by early Wed. Little change then forecast through Thu afternoon 
when a tightening pressure gradient will produce a moderate to 
locally fresh northwest breeze west of the Baja Peninsula.
Locally strong conditions are forecast near 26N113W on Fri night.

Gulf of California: A moderate nocturnal southwest breeze is 
expected along 30N for the next several days. A moderate 
northwest breeze is forecast to begin across the southern Gulf 
of California on Thu.

Gulf of Tehuantepec: Moderate nocturnal drainage flow is expected 
this week.     

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



REMAINDER OF THE AREA...

A surface high is centered near 31N140W with a ridge extending 
southeast to near 13N108W. Moderate trades are observed south of 
the ridge with 5 to 8 ft seas currently observed near 12N123W 
are forecast to subside to 4 to 7 ft tonight, with little change 
then forecast through Thu. The pressure gradient is forecast to 
tighten as a surface low  develops along the ITCZ near 10N132W 
late this week resulting in fresh to possibly strong trades 
north of low with seas building to 8 ft.

Further north...the surface high will dissipate as the ridge 
shifts south on Wed allowing a cold front to reach along a 
position from 32n 137W to 30N142W tonight. The front will 
continue east eventually losing identity from 32N126W 24N128W on 
Thu night into Fri. Although only fresh winds northerly winds 
are forecast west of the front, northwest swell will miantain an 
area of 6 to 8 ft seas across the waters from 29N to 32N through 
Fri morning. 

$$
Nelson