000
AXPZ20 KNHC 192206
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC surface analysis and satellite imagery through
2100 UTC.     
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              

The monsoon trough extends from 09N81W to 08.5N90W to 07N106W.
The ITCZ extends from 07N106W to 09.5N119W to beyond 04N140W.
Scattered moderate to strong convection is from 05N to 10N
between 84W and 105W. Widely scattered moderate to strong
convection is within 150 nm north of the ITCZ from 130W-138W.

...DISCUSSION...                                             

The main feature influencing the wind flow pattern over the
majority of the discussion area is a 1038 mb high pressure
system centered well northwest of the area near 43N145W, with a
ridge axis extending southeastward through 30N136W to 23N121W
then weakly to near 15N106W. The pressure gradient between the
ridge and the ITCZ/monsoon trough to the south is supporting
moderate to fresh trade winds, mainly south of 21N and west of
120W. The high is expected to remain relatively stationary and
weaken over the next day or so. This should result in a modest
weakening of the trade winds. 

North-northeasterly swell that originated off the California
coast is responsible for seas to 8 ft north of a line from
30N126W to 28N131W to 28.5N140W late this afternoon. A deep-
layered trough building over the northeastern portion of the
forecast area will send a weak surface cold front into the
northeast waters this evening and force the ridge westward.
North-northwest winds behind the front well north of the area
will bring a new pulse of swell into the northern waters Friday.
This north-northwest swell will subside overnight Friday night,
with seas to 8 ft confined north of 29N between 119W-122W by the
end of the period Saturday morning.

Scattered moderate to strong convection is noted over the
eastern portion of the area from 05N-10N between 84W-105W.
Precipitable water animations show abundant low-level moisture
across this area gradually shifting westward...and extending
northwest to coastal areas of Central America from Costa Rica to
near the Tehuantepec region of Mexico. Atmospheric conditions
are generally favorable for continued shower and thunderstorm
activity across this area. Expect clusters of convection to
develop off and on across the area and propagate westward here
through Friday.

Gulf of California... 
Low pressure associated with the Gulf of California thermal
trough is forecast to develop over the far northern Gulf of
California Friday afternoon, with strong south to southwest
winds occurring within 60 nm of the low. Seas across the far
northern Gulf will build to 6-8 ft Friday evening through
Saturday morning before the low shifts off the NE Saturday
afternoon and winds diminish 15 kt. This same scenario may
repeat itself again Saturday night through Sunday.

$$ 
Stripling