000
AXPZ20 KNHC 021546
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL
1605 UTC Fri Sep 02 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
1545 UTC.
  
...SPECIAL FEATURE... 

A broad area of low pressure embedded within the monsoon trough
is analyzed with a mean center near 12N95W, with an estimated
pressure of 1009 mb at 1200 UTC. Scattered moderate to strong
convection is currently observed within 150 nm either side of a
line from 11N91W to 16N104W. Although the convection is
disorganized, atmospheric and oceanic conditions are favorable
for rapid intensification, and this low has a high potential for
tropical cyclone development over the next 5 days as it tracks
northwestward reaching estimated positions near 14N99W on Sat,
near 15N100W on Sun, near 18N107W on Mon and near 21N110W on
Tue. Fresh to locally strong southwesterly flow is currently
observed s of the monsoon trough axis and this embedded low,
roughly within the area from 09N to 11N between 91W and 107W,
with combined seas of 6 to 8 ft primarily due to 3 to 4 second
southwest swell.

As the pressure gradient tightens tonight, strong cyclonic winds
are expected to develop initially over the se semicircle of the
low. Although currently disorganized, the array of global model
guidance suggest strong to near gale conditions could gradually
develop over the e semicircle of the low beginning late Sat. Due
to the close proximity to the Pacific coast of Mexico, these
winds, and the resultant high seas and surf, could reach the
Pacific coast of Mexico between 96W and 101W as early as Sat
night. These strong, or higher winds, will shift northward along
the Mexican coast through early next week, and likely spread
into the southern Gulf of California on Tue. Scattered to
numerous thunderstorms will most likely reach the coast as well,
and result in high rainfall accumulations and possible mudslides
near elevated terrain.    

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

The monsoon trough axis extends w from the Pacific coast of
Costa Rica at 10N82W, through an embedded 1009 mb low pressure
center estimated at 12N95W, then continues nw 12N107W...then
turns sw through a 1011 mb low pressure at 10N120W, and then
continue w to beyond 10.5N140W. 

Scattered moderate isolated strong convection is observed e of
the low pressure at 10N120W, roughly within 90 nm of 11N118W.
Isolated moderate to strong convection is observed within 75 nm
of 05N80W. Scattered moderate isolated strong convection is
observed within 90 nm either side of a line from 06N92W to
09N96W, and elsewhere within 90 nm either side of a line from
11N113W to 08N128W to 12N135W to 11N140W. 

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

See special features section above for the discussion on a
tropical low, or tropical cyclone, that is developing just s of
the Gulf of Tehuantepec, and tracking northwestward through the
offshore waters through the middle of next week.  

Otherwise, a sub-tropical ridge axis extending se just to the w
of the offshore waters, will maintain gentle to moderate nw
flow, with 5 to 7 ft combined seas, across the waters along the
Pacific coast of Baja through Sun, with fresh nw flow expected
to develop within 120 nm of Baja Peninsula on Sun evening
through Mon night. Light and variable winds are forecast
elsewhere in the offshore waters s of the Gulf of California
surrounding the cyclonic winds associated with the tropical low.

A thermal trough will meander over the Baja Peninsula, and
across the northern Gulf of California supporting light and
variable flow across the Gulf of California through Mon, except
increasing to moderate to fresh southerly flow between 30N and
31N tonight, and fresh to locally strong southerly flow is
expected in the same area on Sat night. As mentioned, winds and
seas conditions are anticipated to deteriorate across the
southern Gulf of California beginning on Mon night, and then
spread n across the entire gulf waters by the middle of next
week. 

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

See special features section above for discussion on a tropical
low near 12N95W that is expected to move n across the western
waters of offshore zone PMZ111 through tonight accompanied by
fresh to strong sw flow.

Gentle westerly winds and 3 to 5 ft seas expected elsewhere n of
05N, and moderate to locally fresh southerly flow and 3
to 5 ft seas forecast s of 05N through the period.
 
REMAINDER OF THE AREA...

Except as previously mentioned, a quasi-stationary surface ridge
extending from near 32N140W to near 13N113W will shift slightly
n as the monsoon trough shifts n through the weekend.

Moderate to fresh ne to e flow will continue through late Sat s
of the ridge and n of the monsoon trough, with combined seas of
4 to 7 ft. The gradient should relax some late in the weekend.
  
An ill-defined tropical low currently near 10N120W will move w
and gradually lose identity in the monsoon trough on Sat. Fresh
to locally strong sw flow currently observed within 90 nm se of
a line from 11N112W to 08N123W, is forecast to diminish to 15 to
20 kt on Sat. 

$$
Nelson