000
AXPZ20 KNHC 210901
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
901 UTC Wed Jun 21 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 0600 UTC surface analysis and satellite imagery through
0830 UTC.

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

The monsoon trough axis extends from 09N75W to 11N86W to 15N93W 
to 11N103W to 09N129W. The intertropical convergence zone axis 
extends from 09N129W to 08N140W. Scattered moderate and isolated
strong convection is N of 07N E of 80W, including the Gulf of
Panama, within 210 nm S and SW of a line from 05N77W to 05N85W to
09N91W, from 09N to 11N between 107W and 110W, and also from 08N
to 10N between 116W and 123W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

High pressure of 1034 mb, located well north of the area near 
43N136W, extends a ridge SE to near Clarion Island. The ridge 
will shift westward through late today as a surface trough 
develops near the Baja California Peninsula, where pressures are 
falling. Moderate northwest winds will persist off the coast of 
Baja California norte, shifting to the southwest off Baja 
California Sur starting later this morning as the above mentioned
trough develops and shifts westward.

In the Gulf of California, moderate SE to S winds are forecast 
to increase to fresh across the northern part tonight into
Thursday, and then again on Sunday night.

Long period northwest swell of 6 to 9 ft will continue to
propagate through the waters offshore of the Baja California
peninsula through Friday.

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

Gentle to moderate SW to W winds are expected across the entire 
forecast area today, then the pressure gradient will gradually 
relax with a gentle SW breeze continuing through Sunday night,
except will increase to moderate S of 06N Saturday night through
the end of the weekend. Long period SW swell of 5 to 7 ft will
gradually decay this weekend.

REMAINDER OF THE AREA...
 
A ridge dominates most of the waters N of the convergence zone. 
Scatterometer and altimeter passes from the past several hours 
indicated an area of moderate to fresh winds and seas of 8 to 10 
ft roughly north of 23N and west of 120W. The ridge will continue
to dominate the waters N of the convergence zone today, shifting
W as troughing developing near the Baja California peninsula 
also drifts W. A broad and weak low pressure is forecast to 
develop along the trough axis near 18N118W by tonight.

Northerly swell will continue to propagate across the waters N of
20N, building to 10 to 12 ft N of 27N Thursday through Friday as
fresh swell moves in around a low pressure system N of the area.
Seas will decay through the upcoming weekend as the low moves NW
while weakening.

$$
Lewitsky