000
AXPZ20 KNHC 231501
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1501 UTC Mon Oct 23 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 1200 UTC surface analysis and satellite imagery through
1500 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
this morning as the cold front moves through the western Gulf of
Mexico. Winds are forecast to further increase to storm force
Tuesday night, 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 next weekend.

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

The monsoon trough extends from 10N86W To 07N107W to 08N127W.
The intertropical convergence zone extends from 08N127W to 
09N140W. Scattered moderate and isolated strong convection is
within 105 nm SW of the coast of Panama and Costa Rica, from  
10N to 14N between 99W and 102W, from 10N to 13N between 118W 
and 129W, and also from 06N to 11N W of 128W.

...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.

Seas in the Baja California offshore waters continue in the 7 to
10 ft range. Seas will continue to gradually subside to less 
than 8 ft off Baja California Sur and within 200 nm of the coast 
of Baja California Norte through later today. 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, 
however, a reinforcing set has arrived near 30N140W. 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.

$$
Lewitsky