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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 220800
TWDEP 

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

...TROPICAL WAVES...

A tropical wave axis extending from 17N100W to 04N102W is moving 
west at 15 kt. Scattered moderate isolated strong convection in 
an area bounded by 12N98W to 07N107W to 14N105W back to 12N98W. 
An area of low pressure is expected to develop from this wave by 
early next week, and a tropical cyclone may eventually develop 
as the tropical low becomes better organized south of Mexico.

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

The monsoon trough extends from coast of Costa Rica near 10N86W 
to 14N107W to 1011 mb low pressure near 13N106W to 08N122W. The 
ITCZ continues from 08N122W to 10N138W. Scattered moderate 
convection is within 120 nm either side of the convergence zone 
axis west of 114W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Moderate NW winds west of Baja California will diminish through 
Sat night, and a broad surface trough will prevail along the 
length of the peninsula through Sun morning. Southerly winds 
will increase east of the trough axis in the Gulf of California 
this weekend, becoming fresh to strong southeasterly N of 29N 
Sat afternoon, continuing into early Sun morning. Seas in the 
northern Gulf of California will build to 6-8 ft by Sat night, 
then subside Sun along with a decrease in surface winds. Long 
period cross-equatorial SW swell will reach the waters off 
Southern Mexico this afternoon, and build seas to near 7 ft in 
offshore waters by Sat. Seas will subside there Sun and Mon.  

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

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, with seas building 
to around 8 ft S of 08N by early Sat, then gradually subside on 
Sun and Mon.

REMAINDER OF THE AREA... 

Low pressure centered near 14N116W is embedded in 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. The 
GFS forecast is much more aggressive with this low than other 
global models, and considered an outlier at this point. However, 
this low merits close observation over the next few days for 
signs of increased organization. 

A trough is analyzed from 14N137W to 07N140W. Scattered moderate 
convection is associated with this feature. Seas to 8 ft are 
evident near the trough axis in latest altimeter sea state data. 
The trough will drift westward, and move west of 140W tonight.

Elsewhere, high pressure centered well north of the area extends 
a ridge SE to near the Revillagigedo Islands. Gentle to moderate 
trades prevail west of 120W, and light to gentle winds dominate 
the remainder of the basin, based on latest ASCAT data. 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.

$$
Mundell