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000
AXPZ20 KNHC 232110
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2013 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 1800 UTC surface analysis and satellite imagery through
2100 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 afternoon 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 early next week.

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

The monsoon trough extends from 10N86W To 08N105W to 09N115W.
The intertropical convergence zone extends from 09N115W 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 through tonight,
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