000
AXPZ20 KNHC 190908
TWDEP 

TROPICAL WEATHER DISCUSSION                                  
NWS NATIONAL HURRICANE CENTER MIAMI FL                      
1005 UTC THU MAY 19 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
0700 UTC.     
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              

The monsoon trough axis was analyzed from 10N87W to 07N101W to
08N110W. The ITCZ axis was analyzed from 08N110W to 09N116W,
then continues from 09N121W to 06N140W. A surface trough was
analyzed from 13N116W to 08N120W. Isolated moderate convection
was found within 270 nm south of the axis between 90W-98W.
Scattered moderate convection was found from 10N-13N east of the
surface trough to 108W.

...DISCUSSION...                                             

The driving high pressure over the eastern North Pacific is well
northwest of the area near 42N145W, with a ridge axis extending
southeastward through 30N137W to 16N111W. The pressure gradient
between the ridge and the ITCZ/monsoon trough to the southwest
is supporting mainly moderate to fresh trade winds. The high is
expected to remain relatively stationary and weaken over the
next day or so, weakening the trade winds. A weak surface trough
currently found from 13N116W to 08N120W is forecast to continue
west around 8 kt. Convection near this trough is described
above. Little change is expected in the amount and intensity of
convection near this trough over the next two days.

North-northeasterly swell that originated off the California
coast is responsible for seas to 9 ft north of 28N and west of a
line from 30N128W to 28N132W this morning. A deep-layered trough
building over the northeastern portion of the forecast area will
send a weak surface cold front into the northeast waters later
today and force the ridge westward. North-northwest winds behind
the front well north of the area will send a new batch of swell
into north waters Friday. This north-northwest swell will
subside overnight Friday night, with seas to 8 ft confined north
of 29N between 119W-123W by the end of the period Saturday
morning.

Scattered moderate to strong convection was found north of 12N
to the coast east of 93.5W. There is plentiful low-level
moisture in this area. An anticylone aloft centered near 12N104W
extends a ridge axis eastward toward El Salvador. This upper
pattern is expected to change little over the next two days, but
the available moisture is expected to wane a bit. There is a
good chance that convection will persist over this area, but it
may not be as widespread or intense from tonight onward.

$$ 
Schauer