000
AXPZ20 KNHC 150812
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0811 UTC Tue May 15 2018

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
0745 UTC. 
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough axis extends from northwestern Colombia near 
10N75W to 09N94W to 09N100W to 14N110W to low pressure near 
11N116W 1010 mb to 07N122W to 04N129W, where latest 
scatterometer data indicated that it transitions to the ITCZ to 
03N154W. Scattered strong convection is within 360 nm south of 
the trough between 109W and 111W and within 60 nm north of
the trough between 112W and 114W. Scattered moderate convection 
is within 240 nm south and 120 nm north of the trough between 
114W and 119W, also within 180 nm south of the trough between 
86W and 90W and within 180 nm south of the trough between 94W and
100W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A NW to SE oriented high pressure ridge prevails across the 
offshore waters west of Baja California, producing fresh NW
winds over those waters. These winds will remain at fresh speeds
through Wed, then increase to fresh to locally strong Wed night 
as the ridge strengthens slightly. Altimeter data from last
night indicated that seas were just below 8 ft, in the 5-7 ft 
range. They will change little through tonight before building 
slightly on Wed to 6-8 ft in SW swell mixed with fresh NNW wind 
swell. 

The gradient offshore Baja California will tighten more than 
what it has been during the past several days as the above
mentioned ridge strengthens. This will lead to NW winds offshore
most of the peninsula to increase to strong speeds beginning 
late Wed afternoon or evening, with seas remaining at 6-8 ft. 
Model guidance indicates that these winds will continue through 
Thu night.

Gulf of California: S to SW winds of around 15-20 kt over a 
small section of the northern Gulf of California from 30N to 
30.5N W of 113W will become light and variable Tue. Gentle to 
moderate NW winds will continue across the remainder of the Gulf 
through Wed, except for fresh NW winds along the coast of
Mexico from 24N to 26N beginning late this afternoon through Wed
evening.

Gulf of Tehuantepec: Winds are light to gentle S to SW in 
direction. Winds will briefly become moderate fresh N to NE 
tonight into Wed morning, then become gentle S to SW winds
on Wed afternoon. This cycle of changing winds will repeat
through Thu as a weak pressure pattern remains over Mexico
and Central America.
  
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR... 

Gulf of Papagayo: Light to gentle winds will dominate the gulf 
most of the forecast period with seas of 5-6 ft diminishing 
slightly today to 4-5 ft in long period SW swell. A strong pulse
of cross equatorial SW swell will move into the regional waters 
beginning Wed, and build seas to 5-7 ft Thu through Sat. 
  
Gulf of Panama: Gentle to moderate S to SW winds are forecast 
during the next several days, with seas of 4-6 ft in long period 
southerly swell, building to 5-7 ft Wed night through Sat as 
long period SW swell reaches the coasts of Panama and Colombia.

Elsewhere, gentle to moderate SW winds are expected to the south
of the monsoon trough with its axis roughly along 09N/10N, with 
light to gentle variable winds north of trough. Seas are forecast
to build to 6-7 ft in long period SW swell between Ecuador and 
the Galapagos Islands beginning on Wed. 

REMAINDER OF THE AREA...

A ridge extends from the NW waters southeastward to near the 
Revillagigedo Islands. The pressure gradient between the ridge 
and the monsoon trough and ITCZ to the south is presently weak, 
and yielding moderate NE-E trades between about 10N and 22N to 
the west of 110W. Seas across this area of trades are 6-8 ft, 
and should change little through Thu. The ridge will shift 
slightly southeastward through Wed, with the resultant pressure 
gradient forecast to induce a slight increase of trades across 
the tropics. Stronger high pressure is then forecast to build 
southeastward over the northern portion of the discussion area, 
with and even tighter gradient expected to lead to trades increasing
to fresh to strong speeds. Seas are expected to increase to 7-9 
ft Thu into Fri.

Decaying NW swell is propagating through the waters north of 21N
between Baja California and 117W, where seas are peaking at 7-8 
ft. These seas will subside to less than 8 ft late tonight and 
change little through Thu.

$$
Aguirre