000
AXPZ20 KNHC 071713 AAA
TWDEP 

Tropical Weather Discussion...updated
NWS National Hurricane Center Miami FL
1713 UTC Thu Sep 07 2017

updated to include mention of tropical wave along 90W/91W 

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
1515 UTC.

...TROPICAL WAVES...

A tropical wave axis extends along 90W/91W N of 07N, moving 
westward at 10-15 kt. Scattered moderate convction is within 120 
nm W of the wave axis from 07N-09N. Isolated showers and 
thunderstorms are within 120 nm E of the wave from 07N-09N.

INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough axis extends from 10N86W to 11N91W to 11N100W
to 15N110W to 10N122W to 12N135W. ITCZ extends from 12N135W to 
beyond 10N140W. Scattered moderate isolated strong convection is
within 120 nm S of the axis between 81W and 84W, and within 120
nm S of the axis between 100W and 103W.
  
...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A weak surface ridge covers the NW forecast area and extends E 
to Baja California adjacent waters. A NW to SE oriented trough 
is along the Baja California Peninsula. The pressure gradient 
between these two features supports moderate NW winds W of the 
Baja California Peninsula north of 27N E of 120W. These winds 
will diminish on Friday morning.

Gulf of California...Light southerly winds are expected through 
early Fri, then increase to a moderate breeze through the 
weekend.

Gulf of Tehuantepec: A gap wind event with fresh to strong winds 
and seas to 8 ft is forecast from Sat night through Sun morning. 
Winds will pulse again at night on Sun night.  

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...
    
Light and variable flow is expected N of the monsoon trough Sat 
night, then the pressure gradient will tighten with fresh 
monsoonal flow from the equator to along 09N, with seas building 
from 6 to 8 ft. 

REMAINDER OF THE AREA...

A weak 1021 mb high is centered near 28N138W, with a ridge
extending eastward to 120W. A stationary front stretches from 
32N136W SW to well W of the area. The gradient between the ridge
and lower pressure associated with the monsoon trough will 
maintain gentle to moderate trades N of the monsoon trough W of 
120W, with seas of 5 to 6 ft through Friday.

A surface trough extends from 18N136W to 14N137W to 10N136W. The
pressure gradient between the trough and the ridge to its N and 
NE is supporting an area of fresh NE to E winds from 14N to 19N
between 136W and 139W, with seas up to 9 ft. Latest satellite 
imagery shows scattered moderate isolated strong convection 
within 120 nm W of the trough. The trough is forecast to move W 
of 140W by Friday evening, with an area of seas in the range of 
6 to 8 ft lingering from 15N to 17N W of 138W. These seas are 
expected to subside to less than 8 ft by late Saturday afternoon.
  
Fresh monsoonal flow will develop Fri morning N of the Equator 
to along 10N east of 115W, with seas building to 8 to 9 ft 
through Saturday night. 

$$
Aguirre