000
AXPZ20 KNHC 181550
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Thu May 18 2017

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
1530 UTC.

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

The Monsoon Trough axis extends from 10N85W to 09N96W to 07N107W.
The ITCZ axis extends from 07N107W to 07N119W to 05N130W to
beyond 04N140W. Scattered strong convection is within 60 nm north
of the axis between 133W and 135W, within 60 nm either side of
the axis between 135W and 138W, and within 120 nm north of the 
axis west of 138W. Scattered moderate convection is noted within
60 nm either side of the ITCZ axis between 122W and 126W. Similar
activity is also within 30 nm of 07N95W and of 06N99W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Moderate to fresh northwest winds are off the coast of the Baja 
California peninsula. Light to gentle mainly southwest to west 
winds continue over the Gulf of California, except for stronger
winds in the fresh range from the northwest to north in direction
over the northwest sector of the northern portion of the Gulf.
Gentle to moderate northwest to north winds are evident 
elsewhere. Seas are in the 8 to 10 ft range off the coast of 
Baja California Norte due to a northwest swell, with the highest
of these seas north of 29N. Seas are in the 6 to 7 ft range off 
the coast of Baja California Sur, 1 to 3 ft over the Gulf of 
California, and 4 to 6 ft elsewhere. The northwest swell will 
be rather short-lived as Wave model guidance suggests that it
will dissipate by early on Friday allowing for seas to lower
below 8 ft.

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

Gentle to moderate south to southwest winds are over the 
offshore waters west of Ecuador, while light to gentle southwest 
to west winds are present elsewhere except for west to northwest
mainly light winds north of 09N. Seas are in the 5 to 7 ft range
in southwest swell west of Colombia, 6 to 8 ft in southwest
swell west of Ecuador, and 4 to 6 ft seas in southwest swell 
elsewhere. The southwest swell is forecast to propagate northward
to the waters west of Colombia by Friday evening and into
Saturday, then begin to subside Saturday night, with seas
lowering to below 8 ft early on Sunday. 

REMAINDER OF THE AREA... 

High pressure of 1029 mb, centered northwest of the area near 
36N139W extends a ridge southeastward to near the Revillagigedo 
Islands. The pressure gradient between the ridge and lower 
pressure in the vicinity of the ITCZ is maintaining moderate to 
fresh trades north of the ITCZ west of 120W. Seas in this trade- 
wind belt are in the 6 to 9 ft range due to mixed northeast wind
waves and northwest swell. The high pressure is forecast to 
pull off to the northeast further away from the area through the
weekend. This will allow for the pressure gradient to slacken
leading to winds and seas to decrease over the area through this
time. 

The former nearly stationary weak low pressure of 1010 mb near 
the position of 12N100W has weakened further to a trough along a 
position from near 16N100W to 10N102W. Latest satellite imagery 
shows scattered moderate isolated strong convection associated 
with the trough within 30 nm of 12N102W. The convection is 
expected to weaken this afternoon, while the trough gradually 
becomes diffuse through Friday.

$$
Aguirre