000
AXPZ20 KNHC 300901
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
518 UTC Fri Sep 30 2016

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 0600 UTC surface analysis and satellite imagery through
0900 UTC.

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

The monsoon trough extends from 07N78W to 10N85W to 09N91W to
12N107W. It resumes at 11N113W to 09N123W to low pressure near
13N134W. Scattered moderate isolated strong convection is noted
within 60 nm south of the monsoon trough east of 83W. Scattered
moderate convection was noted within 90 nm south of the monsoon
trough between 113W and 116W. Scattered moderate convection was
noted within 30 nm north and 60 nm south of the monsoon trough
between 122W and 125W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Post-tropical remnant low of Roslyn is centered near 24.5N
116.5W. Winds and seas associated to this feature have fallen
below advisory criteria. The low is forecast to dissipate by this
afternoon.

A weak pressure gradient over the forecast waters is supporting
mainly light to gentle winds across the area. The exception to
this is in the Gulf of Tehuantepec where gap winds are reaching
near gale force. Seas are in the 4-6 ft range north of 20N outside
the Gulf of California, 6-7 ft south of 20N, and 2 ft or less over
the Gulf of California. Seas are reaching near 10 ft in the area
of near gale force winds over the Gulf of Tehuantepec.

A surface trough is noted from 21N111W to low pres near 17N111.5W
to 11N111W. This low will continue to propagate west northwestward
over the next few days. Once the remnant low of Roslyn dissipates,
high pressure will build back across the northern waters. This
will bring an increase to the winds north of 20N over the weekend
and into early neat week with seas building to 6-8 ft north of 25N
by Monday night. 

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...

Light and variable winds are expected north of the monsoon
trough, while gentle to locally moderate south to southwesterly
winds are expected south of the monsoon trough through the
upcoming weekend. Combined seas of 4 to 7 ft, primarily in long-
period southwesterly swell is expected across the offshore waters
through the upcoming weekend.

REMAINDER OF THE AREA... 

Tropical Storm Ulika has moved west of 140W and its influence on
the forecast waters will continue to decrease, with winds and seas
falling below advisory criteria today. High pressure will build
over the northern waters which will increase the pressure
gradient, freshening winds north of the monsoon trough this
weekend. The long fetch of these fresh trades will help build seas
to the 7-9 ft range early next week. 

$$
AL