000
AXPZ20 KNHC 180905
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
905 UTC Tue Oct 18 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
0830 UTC.

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

The monsoon trough extends from Costa Rica near 10N83W to 13N96W
to 10N100W to 11N103W TO 11N110W to 1008 mb low pres near 10N113W
to 09N116W to 14N130W to 1008 mb low pres near 14N133W to 10N140W.
Scattered moderate and isolated strong convection is within 180 nm
either side of the monsoon trough axis E of 134W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A high pres ridge extends SE from 34N138W to near the
Revillagigedo Islands at 18N110W. Fresh to strong NW to N winds
are occurring within 100 nm of the coast of Baja California N of
28N. Moderate to fresh N winds are present elsewhere W of Baja
California. The combination of winds and NW swell support seas of
8 to 10 ft W of Baja California Norte. NW swell of 6 to 8 ft are
propagating SE to offshore of Baja California Sur. Winds in this
area will lessen slightly on Tuesday as the ridge shifts to the
NE. Winds will be light to moderate Thursday and Friday as the
ridge to the N remains weak in response to an approaching cold
front. The large swell will begin to subside on Tuesday and
Wednesday, then subside. Seas in this area will subside below 8 ft
by Friday.

Fresh to strong N winds over the Gulf of Tehuantepec have
decreased, but will pulse to fresh each night through Wednesday
night. A strong area of high pres behind a cold front over the
Gulf of Mexico will support fresh to strong N to NE Tehuantepec
gap winds Thursday night, then Gale force winds Friday through
Monday. Model guidance suggests that winds could reach strong
gale force Saturday through Sunday night.

Elsewhere, light to gentle winds prevail. Surface troughing over
the Baja peninsula is promoting a light wind regime over the Gulf
of California. Seas are generally 2 ft or less there, and around
4-6 ft elsewhere. Fresh to strong winds may develop over the
northern Gulf of California Wednesday night through Thursday night
as the pressure gradient tightens between the high pres ridge W
of Baja and low pres over Arizona.

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

Moderate to fresh SW winds are evident S of the monsoon trough.
Mainly light to gentle winds continue N of the monsoon trough.
Seas are in the 4-6 ft range N of the monsoon trough in a mix of
NW and SW swell. Seas of 5-7 ft are S of the monsoon trough in
primarily SW swell. These conditions are forecast to prevail
through Friday.

REMAINDER OF THE AREA... 

1008 mb low pres is centered near 14N133W. This system has a low
potential to become a tropical cyclone during the next few days as
it moves W to WSW. The pres gradient between the high pres ridge
NW of the Revillagigedo Islands and the low is generating fresh to
strong winds in the NW semicircle within 360 nm of the low, with
seas of 9-11 ft. Elsewhere, moderate to fresh winds will prevail
between the monsoon trough and the ridge the next couple of
days...except light and variable winds along the ridge axis. A NW
swell event that has been affecting the area the last few days.
The event is being reinforced by another batch of NW swell
entering the NW waters. Swell greater than 8 ft generally covers
the area N of a line from 19N112W to 10N140W. This area of swell
will persist until mid week, then decrease in size Tuesday and
Wednesday. On Thursday 8 ft seas will be concentrated in the
vicinity of the low, which will be near 13N139W and W of Baja N of
25N between 119W and 130W. Elsewhere, the combination of SW winds
S of the monsoon trough and NW swell will support seas of 8-10 ft
mainly from 03N and 12N between 96W and 125W through Saturday. SW
swell of 8-9 ft will propagate NE between 95W and 115W and cause
seas S of 02N to build to between 8 and 9 ft Tuesday through
Thursday, then seas in this area will subside below 8 ft.

$$
FORMOSA