000
AXPZ20 KNHC 181507
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1109 UTC Sat Jun 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...         

The monsoon trough extends from 10N86W to 09N99W to 12N110W to
12N121W TO 09N127W. The ITCZ extends from 09N127W to 08N132W to
08N140W. Scattered moderate to isolated strong convection is noted
north of 05N and east of 90W. Scattered moderate convection is
noted within 240 nm south of the monsoon trough between 92W and
100W. Scattered moderate convection was noted within 90 nm either
side of the ITCZ between 132W and 138W.

...DISCUSSION...   

North of 15N east of 120W:

Weak 1012 mb low pressure in the vicinity of the Revillagigedo
Islands will dissipate by tomorrow. High pressure will build over
the northern waters. This will help tighten the pressure gradient
over between the area of high pressure and persistent troughing
over the Gulf of California. Winds will strengthen north of 28N
between 116W and 122W with seas building to near 8 ft by Sunday
morning. These winds will diminish Monday as the trough shifts
westward off the coast of the Baja California peninsula. Long
period southwest swell start to move north of 15N early next week.
The pressure gradient between high pressure building over the
Gulf of Mexico and the monsoon trough over the eastern North
Pacific will help for strong gap wind flow into the Gulf of
Tehuantepec. The mix of shorter period wind waves from the gap
winds and the longer period southwest swell will result in areas
of confused seas in and downstream of the Gulf of Tehuantepec. In
addition, the swell will allow the potential for hazardous surf
along exposed areas of the coast of Mexico starting late Monday
through mid week.

South of 15N east of 120W:

Gentle to moderate monsoonal flow prevails to the south of the
monsoon trough. Gentle to moderate northeasterly trade winds
prevail to the north of the monsoon trough. Subsiding southwesterly
swell continues to propagate across the area with seas in the 5 to
6 foot range from 100W westward, and in the 3 to 5 foot range
from 100W eastward. A fresh set of long period southwesterly swell
will move into the area starting late Sunday. Wave heights will
build to 6 to 9 ft. The swell will reach the coast of Central
America by mid week.

West of 120W:

A surface trough, the remnants of a dissipated cold front,
reaches from 30N128W to 24N140W. The trough will drift westward
later today as high pressure continues to build across the region
north of 25N. The pressure gradient between this area of high
pressure and low pressure in the monsoon trough and in the
vicinity of the ITCZ is supporting moderate to fresh winds with
seas in the 4 to 7 foot range. The ridge will prevail in the
northern waters during the next few days with these general
conditions persisting. A surge of northerly winds off the coast of
Southern California will push south of 32N by Monday day, bringing
fresh to strong winds as far south as 28N between 120W and 126W
with seas to 8 ft by early next week.

$$
AL