000
AXPZ20 KNHC 311536
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1511 UTC Sun Jul 31 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.
  
...SPECIAL FEATURES... 

Low pressure embedded in the monsoon trough near 14.5N120W at 1007
mb continues to show signs of organization. Scattered moderate and
isolated strong convection is within 210 nm in the southeast and
120 nm in the northwest semicircles of the low. Overnight
scatterometer data indicated fresh to strong winds within 240 nm
in the se semicircle where seas are also 8 to 10 ft. The low is
forecast to continue to move to the west-northwest around 5 to 10
kt today, and then more northwesterly thereafter. The low has a
high chance of tropical cyclone formation during the next 48
hours.

...TROPICAL WAVES...

A tropical wave along 106W northward of 05N is moving west at 10
to 15 kt. Scattered moderate convection is from 09N to 17N
between 97W and 103W, and also from 10N to 14N between 93W and
97W. Model guidance continues to indicate the potential for broad
low pressure to form along the wave axis in the next few days.

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

The monsoon trough axis extends from 09N80W to 08N93W to 10N106W
to low pressure near 14.5N120W to 10N140W. Scattered moderate
convection is from 06N to 10N between 109W and 114W, and also
within 150 nm to the south of the axis between 123W and 138W.

Also, scattered moderate convection is from 21N to 23.5N within
120 nm west of the coast of Mexico. This convection developed
overnight across Jalisco and Nayarit before propagating offshore.

...DISCUSSION...   

N of 15N E of 120W:

In the Gulf of California, weak surface troughing will linger
along the Baja California peninsula for the next several days.
Light to moderate southerly flow will prevail across the northern
Gulf, with northerly flow across the southern Gulf.

Across the Gulf of Tehuantepec, nocturnal northerly flow will
pulse to fresh to strong during the overnight and early morning
hours starting late tonight, and occurring each night through
Thursday morning. Seas will build to up to 8 to 10 ft by early
Monday.

Elsewhere, a weak surface ridge extends into the area from the
northwest. This ridging will support mainly gentle west to
northwest flow across the open Pacific waters, occasionally
pulsing to moderate just offshore of the Baja California
peninsula. Seas will remain in the 4 to 6 ft range.

S of 15N E of 120W: 

Across the Gulf of Papagayo, fresh easterly drainage flow is
expected through Monday during the overnight hours helping to
build fresh seas to 7 to 9 ft. Weaker winds are expected through
the rest of the next week as the monsoon trough drifts slightly
northward. Otherwise, light to moderate flow is anticipated on
either side of the monsoon trough.

Long-period, cross-equatorial southwesterly swell producing seas
of 4 to 7 ft will linger through most of the week.

W of 120W:

Ridging extending from northwest of the area is disrupted by the
remnant 1014 mb circulation of Frank, currently near 22N133W.
This low remnant will become a trough later today or tonight.

Fresh to strong northerly winds offshore of California will
generate fresh northerly swells. Seas of 8 ft will propagate
down to 29N by late tonight into early Monday, decaying to less
than 8 ft by the middle of the week.

$$
LEWITSKY