000
AXPZ20 KNHC 180227
TWDEP 

TROPICAL WEATHER DISCUSSION                                  
NWS NATIONAL HURRICANE CENTER MIAMI FL                      
0405 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 0000 UTC surface analysis and satellite imagery through
0130 UTC.     
  
.Intertropical Convergence Zone/Monsoon Trough...                

The monsoon trough extends from 09.5N83W to 07.5N95W to
08N103W...where it transitions to ITCZ...continuing on to
09N112W to 09N123W to 09.5N135W. Scattered moderate to strong
convection noted from 05N to 12N between 79W and 87.5W...and
from 06N to 11N between 90W and 100W. Widely scattered moderate
to strong convection noted within 240 nm n of ITCZ between 109W
and 135W.


.Discussion...                                             

A surface ridge extends from a 1032 mb subtropical high pressure
center that is centered near 36.5N140W through 23N125W to
16N107W. The pressure gradient that exists between the ridge and
lower pressure along the ITCZ/monsoon trough is supporting
mainly moderate to fresh trade winds generally south of 22N to
the ITCZ and west of 120W. Fresh to strong winds of 20-25 kt
area occurring within 240 nm NW of a surface trough that extends
from 05N141W TO 13N132W. Wave model guidance and recent
altimeter data indicate seas across this area are running 8-10
ft in mixed SW swell and NE windwaves. The subtropical high will
migrate northwestward and merge with a new area of surface high
pressure, that is behind a cold front that is well to the north
of the area. The ridge will then shift to the west and weaken,
gradually shrinking the area of fresh tradewinds through
Wednesday afternoon as the surface trough shifts west of the
area. Isolated to widely scattered moderate convection is
located within 240 nm NW of the trough.

Northwest to north swell propagating into northeast portions of
the area is maintaining seas to 8 feet to the north of 29N
between 119W and 126W this evening. This swell is originating in
an area of 20-30 kt winds that is just to the north of the
forecast area off the California coast. The winds and associated
seas will shift westward as the subtropical ridge shifts
westward through Thursday. Combined seas to 9 feet are expected
in the forecast waters that are to the north of 28N to the west
of 126W by the end of the forecast period early Thursday morning.

East of 110W...weak monsoonal flow is found south of the monsoon
trough this evening...while very active convection described
above and associated with a low level wind and moisture surge
are exiting Colombia, Panama, and Costa Rica and gradually
shifting westward. This active convection will continue to
gradually shift westward and past 90w through late Wednesday.
Fresh to strong tradewinds prevail across much of the Caribbean
and are blowing across Central America to produce moderate
easterly winds along the Pacific coast of Nicaragua and Costa
Rica north of 10N. These winds will increase to around 20 kt and
gusty and extend farther offshore tonight and again Wednesday
night...especially across the preferred areas in the Papagayo
region. Elsewhere across Central America, gap winds are not
expected to dominate in the next couple of days.

$$ 
SS