000
AXPZ20 KNHC 130920
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE AUG 13 2013

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...

LOW PRESSURE IS CENTERED NEAR 13.5N130W AND ANALYZED AT 1008 MB 
OVERNIGHT. CONVECTION ASSOCIATED WITH THIS FEATURE REMAINS 
SHEARED OVER THE W QUADRANT OF THE LOW. THERE IS AN OPPORTUNITY 
FOR THE LOW TO BECOME BETTER ORGANIZED OVER THE NEXT COUPLE OF  
DAYS...AND IT HAS A MEDIUM CHANCE OF INTENSIFYING INTO A 
TROPICAL CYCLONE OVER THE NEXT 48 HOURS AS IT TRACKS IN A 
GENERALLY WESTWARD MOTION. 

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

THE MONSOON TROUGH AXIS EXTENDS FROM 10N85W TO 11N90W TO 10N96W 
TO 10N115W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 60 NM 
OF TROUGH E OF 87W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 150 NM N OF TROUGH BETWEEN 90W AND 
92W. 

...DISCUSSION...
 
BREAKDOWN OF THE MONSOON TROUGH REMAINS OVER THE WESTERN HALF OF 
THE FORECAST AREA W OF 115W WITH TWO LOW PRESSURE CENTERS 
EVIDENT...ONE JUST W OF THE AREA CENTERED NEAR 12N145W...AND THE 
OTHER DISCUSSED IN THE SPECIAL FEATURE SECTION ABOVE. A WEAK 
1023 MB HIGH IS ANALYZED NEAR 30N137W WITH ASSOCIATED RIDGE 
EXTENDING SE TO NEAR 25N115W. THE WEAK PRES GRADIENT BETWEEN THE 
HIGH AND PERSISTENT LOW PRES ALONG THE SIERRA MADRES 
OCCIDENTALES HAS BEEN PRODUCING MODERATE TO FRESH NNW WINDS 
ALONG AND OFFSHORE OF THE W COAST OF BAJA CALIFORNIA TO ABOUT 
120W. THESE CONDITIONS ARE FORECAST TO GENERALLY PREVAIL OVER 
THE NEXT 24-48 HOURS. 
 
THE PRES GRADIENT BETWEEN THE AREA OF HIGH PRESSURE AND THE LOW 
PRESSURE MENTIONED ABOVE IN THE SPECIAL FEATURE SECTION IS 
MAINTAINING FRESH TO STRONG WINDS AND SEAS TO NEAR 9 FT IN THE 
NORTHERN SEMICIRCLE OF THE LOW. THESE WINDS AND SEAS ARE 
EXPECTED TO MAINTAIN TO THE N OF THE LOW THROUGH WED AFTERNOON 
BEFORE THE LOW SHIFTS W OF THE FORECAST AREA. WINDS AND SEAS 
OVER THE FORECAST AREA ASSOCIATED WITH THIS LOW WILL THEN 
GRADUALLY DECREASE BELOW ADVISORY CRITERIA THROUGH THU 
AFTERNOON. ASIDE FROM THIS AREA...WINDS AND SEAS OVER THE 
REMAINDER OF THE FORECAST AREA ARE EXPECTED TO REMAIN BELOW 
ADVISORY CRITERIA. 

$$ 
AL