000
AXPZ20 KNHC 240200
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0200 UTC Tue Oct 24 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 0000 UTC surface analysis and satellite imagery through
0200 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Storm Warning:
High pressure building across eastern Mexico in the wake of a
cold front has helped tighten the pressure gradient over the
area. In response to this tighter pressure gradient, northerly
flow funneling through the Chivela pass is reaching gale force as
the cold front moves through the western Gulf of Mexico.
Satellite imagery and reports from Salina Cruz on the Pacific
side of the Tehuantepec isthmus indicate increasing winds into 
the Gulf of Tehuantepec. Winds are forecast to further increase 
to storm force Tuesday night as a reinforcing cold airmass builds
north of the area, with seas building to near 22 ft by midweek. 
The storm force winds should diminish Wednesday evening, with 
gale force winds then persisting into early Thursday. Model 
guidance now indicates that gale or near gale force winds may 
persist through the end of the week, possibly into early next 
week.

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

The monsoon trough extends from 10N85W To 07N105W to 10N135W. 
The intertropical convergence zone extends from 10N135W to 
09N140W. Scattered moderate and isolated strong convection is 
within 120 nm off the coast of western Panama. Scattered moderate
convection is ongoing within 60 nm either side of ITCZ between 
120W and 125W, and west of 135W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please see the special features section above for information on
a developing storm event in the Gulf of Tehuantepec.

Northwest swell with wave heights of 8 to 10 ft will subside to
below 8 ft in the waters off Baja California Sur overnight, with
seas to 8 ft lingering off Baja California Norte beyond 200 nm 
through Tuesday. Gentle breezes associated with a weak pressure 
pattern along with slight to moderate seas will prevail by late 
week. 

High pressure over the Great Basin region of the western United 
States is maintaining fresh to strong winds over the Gulf of 
California. These winds are expected to continue through early
Wednesday, before diminishing as the area of high pressure 
shifts eastward and the pressure gradient weakens. Winds will be 
the strongest today, with seas peaking near 6 to 7 ft.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...
   
Gentle to moderate winds will prevail over the forecast area
the next several days, except fresh to strong S of the monsoon 
trough. The fresh to strong winds will support building seas of 8
to 10 ft SW of western Panama and Costa Rica.

NW swell originating from the Gulf of Tehuantepec will propagate
into the offshore waters of Guatemala and El Salvador by midweek.
Broad low pressure may develop along the monsoon trough by the 
end of the week, drifting to the NW.

REMAINDER OF THE AREA...

An old set of NW swell of 8 to 10 ft has continued to decay,ahead
of a reinforcing set arriving into the waters N of 25N and W of
135W. A combined area of NW swell will then continue to 
propagate SE, but will decay through midweek with seas less than 
8 ft by Wednesday evening. Tranquil marine conditions are 
expected Wednesday night through early Friday. A new large set of
NW swell will breach 30N140W Friday morning with seas rapidly 
building and reaching 14 ft near 30N140W Friday night.

$$
Christensen