000
AXPZ20 KNHC 050956
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Tue Sep 5 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 
0900 UTC.
  
...TROPICAL WAVES...

A tropical wave axis extends from 22N115W to 12N117W, moving 
westward at 15 kt. Scattered moderate isolated strong convection 
is seen within 150 nm E of the wave axis from 16.5N to 18N.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough axis extends from 10N85W to 12N98W to 17N109W 
to 14N123W to 13N140W. Clusters of scattered moderate isolated 
strong convection are evident from 13N to 16N between 97W and 
100W, from 17N to 19N between 103W and 108W, and from 08N to 11N 
between 128W and 133W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

The eastern periphery of a weak ridge over the NW portion of the 
discussion area will build eastward tonight and persist through 
Thursday. The gradient between the ridge and lower pressure over 
Mexico will support mainly gentle to moderate NW winds, and seas 
of 3 to 5 ft today. The pressure gradient will tighten tonight 
through Thursday, resulting in moderate to fresh winds west of 
Baja California Norte with seas of 5 to 7 ft.

Farther south, fresh to strong overnight gap winds are possible 
through the Gulf of Tehuantepec beginning late Thursday night, 
with seas building to near 7 ft. Otherwise, light to gentle 
winds and seas of 4 to 6 ft will prevail.

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

Light and variable winds are expected N of the monsoon trough, 
with moderate to locally fresh southerly winds S of the monsoon 
trough through Thursday, with 4 to 6 ft seas over entire area. 
By Friday, the southerly winds are forecast to increase slightly 
south of the monsoon trough, building seas to 6 to 8 ft. 

REMAINDER OF THE AREA...

A weak high is centered near 26N138W, with a ridge extending E 
to near 120W. The pressure gradient between the high and lower 
pressure associated with the monsoon trough will maintain mainly 
gentle to moderate trades N of the monsoon trough and W of 120W, 
with seas remaining 4 to 6 ft through Friday. Moderate to fresh 
trades are expected to develop N of the trough 128W Wed, then 
gradually shift to near 140W by Friday, with seas of 5 to 7 ft. 
Seas are expected to build to 6 to 8 ft over far western portion 
Thu from 15N to 20N as the gradient tightens somewhat. Long 
period cross-equatorial swell in SW waters will slowly decay 
today, but remain about 5 to 7 ft through Fri.

$$
Mundell