000
AXPZ20 KNHC 072121
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2115 UTC Thu Sep 7 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 1800 UTC surface analysis and satellite imagery through
2115 UTC.

...TROPICAL WAVES...

A tropical wave axis extends along the Yucatan Peninsula into the
adjacent waters from 14N92W to 08N92W, moving westward at 10-15 
kt. Scattered moderate convection is from 07N-17N between 89W-
96W.

INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough extends from 10N86W to a 1010 mb low near 
14N112W to a 1010 mb low near 12N120W to 10N130W to 12N135W. 
Scattered moderate convection is within 120 nm S of the axis 
between 81W and 110W.
  
...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 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 1022 mb high is centered near 28N139W, with a ridge extending 
eastward to 110W. A cold front is north of the ridge analyzed 
from 31N130W to beyond 30N140W. 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 15N137W to 10N140W. 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 17N 
between 134W and 138W, with seas up to 9 ft. Latest satellite 
imagery shows scattered moderate convection within 120 nm N 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 19N W of 137W. 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. 

$$

ERA