000
AXPZ20 KNHC 180922
TWDEP 

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

The monsoon trough axis was analyzed from 10N84W to 07N93W to
08N105W. The ITCZ axis was analyzed from 08N105W to 07N113W to
10N123W to 06N132W to 07N137W. A trough was analyzed from
14N135W to beyond 07N140W. Scattered moderate with isolated
strong convection was from 06.5N to 13N between 84.5W and 90W. 

.DISCUSSION...                                             

The driving high pressure over the eastern North Pacific is well
northwest of the area near 40N150W, with a ridge axis extending
southeastward through 22N126W to 14N105W. The pressure gradient
between the ridge and the ITCZ/monsoon trough to the southwest
is supporting mainly moderate to fresh trade winds. Winds are
enhanced northwest of a surface trough from 14N135W to beyond
07N140W, with the 0622 UTC ASCAT-A pass showing fresh to strong
northeast winds within 150 nm west of the trough from 11N-13N.
The subtropical high will migrate farther northward. The ridge
axis will shift west and weaken as deep-layer troughing builds
over the southwestern United States and over northeast waters,
shrinking the area of fresh trade winds westward. Fresh to
strong northeast winds should remain just west of the trough
until late morning as it continues westward. Convection near
this trough has dissipated.

Northwesterly to northerly swell that originated off the
California coast is responsible for seas to 8 ft north of 29N
between 120W-130W this morning. The aforementioned deep-layered
troughing building over the northeastern portion of the forecast
area will send a weak surface cold front into the northeast
waters Thursday night and force the subtropical ridge westward
with the northerly winds to the north of the area and the swell
moving into waters north of 28N expected to will follow suit.
Combined seas to 9 ft are expected over northwestern forecast
waters Wednesday night through at least Friday morning.

Scattered moderate to strong convection was found from 02.5N-08N
between 76W-79.5W. Strong upper level divergence can be found in
this area between southwesterly flow aloft to the east and
northerly flow aloft to the west. Conditions should remain
favorable for sustained convection in this area south of the
Gulf of Panama through tonight, with low-level moisture
diminishing and winds aloft becoming less favorable for vertical
lift thereafter.

$$ 
Schauer