873 
AXPZ20 KNHC 150901
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL
1005 UTC Sun Jul 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 
0900 UTC.  

...SPECIAL FEATURE...

A broad area of low pressure is analyzed as a weak and 
disorganized 1008 mb surface low near 13N133W with a surface 
trough extending NE to near 16N133W. The pressure gradient will 
support fresh to locally strong trades across the tropics 
roughly within 540 nm N of the low as it reaches near 11N140W 
tonight, and then passes 140W by early Mon. Associated 
conditions should be W of 140W early Tue. This system has the 
potential to become a tropical cyclone. Refer to the EPAC 
Tropical Weather Outlook under AWIPS/WMO headers MIATWOEP/ABPZ20 
KNHC for additional information. 

...TROPICAL WAVES...

A tropical wave is analyzed from 05N95W to 13N96W and is 
estimated to be moving W at 20 kt. Scattered moderate and 
isolated strong convection is observed S of 12N within 180 nm of 
the wave axis.

A tropical wave is analyzed from 06N106W through a 1011 mb 
surface low at 11N106W to 15N106W, and is moving W at 12 kt. 
Scattered moderate isolated strong convection is observed S of 
11N within 240 nm of the wave axis. 

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

The monsoon trough extends W off the Pacific coast of Colombia 
at 08N78W to the Pacific coast of Costa Rica at 09N84W, then 
dips SW through a tropical wave at 07N95W then turns NW and 
loses identity near the surface low at 11N106W. Scatterometer 
winds indicate an ITCZ develops at 10N108W and drops SW to 
07N112W then continues W to 09N128W where it loses identity. 
The ITCZ resumes from 10N137W to 09N140W.

Except as mentioned near the tropical waves, scattered moderate 
isolated strong convection is observed within 90 nm of 05N78W, 
within 120 nm either side of a line from 07N83W to 07N95W to 
09N109W to 09N129W. 
  
Scattered moderate isolated strong convection is observed within 
30 nm either side of a line from 07N81W to 10N85W.
  
...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of Tehuantepec: Pulses of strong northerly drainage flow, 
accompanied by 6 to 9 ft seas, will continue through Wed night.
    
A surface ridge will meander across the area from near 23N116W 
to near 15N100W this week. A moderate NW breeze will develop 
within 90 nm of the Baja Peninsula during the evenings, 
otherwise gentle anticyclonic northerly winds are expected 
around the ridge axis, with 3 to 5 ft seas.   
  
Gulf of California: Moderate southerly flow will continue along 
30N through early Mon morning. Elsewhere, light to gentle 
southerly flow expected for the next 48 hours.  

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

Gulf of Papagayo: 

Gentle to occasionally moderate E winds are forecast elsewhere N 
of the monsoon trough which is meandering between 07N and 10N. 
Moderate southerly winds are forecast S of the monsoon trough 
for the next several days accompanied by 4 to 6 ft seas.

Extended model guidance is suggesting that long period southerly 
swell, in the form of 7 to 8 ft seas, will arrive along 03.4S to 
the E of 93W early Thu, and propagate N reaching the far 
offshore waters along 10N and W of 93W next weekend.   
  
REMAINDER OF THE AREA...
   
Refer to Special Features section above for information on a 
weak surface low near 10.5N133W.  

A surface ridge will meander across the discussion area from 
32N140W to 23N116W this week, with moderate to locally fresh 
anticylonic flow forecast elsewhere around the ridge accompanied 
by 4 to 7 ft seas. 
  
$$
Nelson