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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 222156

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Fri Jun 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 1800 UTC surface analysis and satellite imagery through 
2100 UTC. 


A tropical wave along 101W/102W is moving west at 10 kt and has 
slowed its forward progress today. The wave is presently moving 
through a moist and unstable environment. Scattered moderate to 
strong convection associated with this wave is located from 06N 
to 16N between 97W and 105W. Global models show an area of low 
pressure develop from this wave along 106W this weekend. This 
area will be monitored for potential tropical cyclone 
development SW of Mexico early next week.


The monsoon trough extends from 09N71W TO 07.5N79W TO 13.5N101W 
to 1011 mb low pressure near 13N116W TO 09N121W. The ITCZ 
continues from 09N121W TO 07N127W TO 10N140W. Scattered moderate 
to strong convection is noted from 05.5N to 15.5N between 84W 
and 102W, from 09N to 14N between 102W and 119W, and from 06N to 
13N to the west of 133W.



Moderate NW winds are expected to prevail across the waters west 
of Baja California through early Sat before beginning to 
gradually diminish through the weekend, as a broad surface 
trough extending the full length of the peninsula shifts slowly 
westward across the Pacific waters. Winds west of the peninsula 
will become variable less than 15 kt through the weekend. 
Meanwhile, southerly winds will increase east of the trough axis 
inside the Gulf of California this weekend, becoming fresh to 
strong southeasterly N of 27N Sat afternoon, continuing into 
early Sun morning. Seas in the northern Gulf of California will 
build to 6-9 ft by Sat afternoon and evening, then subside Sun 
along with a decrease in surface winds. 

Further south, long period cross-equatorial SW swell will begin 
to reach the waters off Southern Mexico this afternoon, and 
build seas to 5-6 ft tonight, and reach 7-8 ft by Sun morning. 
Sea will then begin to subside Mon.  


The monsoon trough will meander between 09N and 11N the next 
several days. Light to gentle winds will prevail north of the 
monsoon trough, with gentle to moderate S to SW winds expected 
south of the trough axis. Long period cross-equatorial SW swell 
will spread across southern forecast waters today, with seas 
building to 5-6 ft this evening, and reaching 6-8 ft Sat 
afternoon through Sun, before gradually subsiding Mon.


High pressure centered well north of the area near 36N136W 
extends a modest ridge SE to near the Revillagigedo Islands. 
Moderate to fresh tradewinds prevail S of 27N and west of 125W, 
where seas are generally 6 to 8 ft, while light to gentle winds 
dominate the remainder of the basin westward of 110W. 

Tradewinds will diminish slightly across western portions of the 
area this afternoon through Sat as a trough along 142W shifts 
well west of the area. Seas are currently 8 to 9 ft in mixed NE 
and NW in this area, from 10N to 15N to the west of 137W and 
will gradually subside to 6-7 ft through Sat. A pulse of 
northerly swell will propagate into the northern waters with 
seas building to 6 to 9 ft north of 25N between 120W and 130W 
early Sat. Cross-equatorial southerly swell will build seas to 6 
to 9 ft south of 10N and west of 90W late tonight and continue 
through Sunday evening.

Low pressure centered near 13N116W is embedded along the monsoon 
trough with an estimated pressure of 1011 mb. Model guidance 
shows this low emerging from the trough and drifting northward 
with a gradual increase in intensity through the weekend. Active 
thunderstorms will continue to the east and southeast of this 
low through Sat.