000
AXPZ20 KNHC 102212
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
2205 UTC SAT AUG 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...SPECIAL FEATURES...   
BROAD LOW PRESSURE REMAINS EMBEDDED WITHIN THE MONSOON TROUGH... 
CENTERED NEAR 12.5N119.5W 1010 MB...AND IS NEAR STATIONARY THIS 
AFTERNOON. VISIBLE SATELLITE IMAGERY THIS AFTERNOON SHOWS A FEW 
LOW LEVEL CYCLONIC CLOUD SWIRLS ROTATING CYCLONICALLY ABOUT THE 
MEAN CENTER...WITH DRY AIR AND LITTLE TO NO SIGNIFICANT 
CONVECTION WITHIN 270 NM ACROSS THE EASTERN SEMICIRCLE. ACTIVE 
CONVECTION DESCRIBED BELOW CONTINUES TO THE SW OF THE MEAN 
CENTER...WHERE FRESH NE WINDS ARE CONVERGING WITH S TO SW WINDS 
OCCURRING THE TO S OF THE MONSOON TROUGH. THIS SYSTEM REMAINS 
OVER WARM SEA SURFACE TEMPERATURES...AND IS EMBEDDED WITHIN AN 
AREA OF ABUNDANT TROPICAL MOISTURE...BUT AT PRESENT IS POORLY 
ORGANIZED. THIS SYSTEM IS EXPECTED TO BECOME GRADUALLY BETTER 
ORGANIZED OVER THE NEXT FEW DAYS...AND HAS MODERATE POTENTIAL TO 
DEVELOP INTO A TROPICAL CYCLONE OVER THE NEXT 48 HOURS AND A 
HIGH CHANCE WITHIN THE NEXT FIVE DAYS. 
                       
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 08N74W TO 11N81W 
TO 08N91W TO 08.5N98W TO 10.5N102W...WHERE IT FRACTURES. THE 
TROUGH RESUMES FROM NEAR 17N112W TO BROAD LOW PRES AT 
12.5N119.5W TO WEAK LOW PRES NEAR 12N133W TO 10N140W.  SCATTERED 
MODERATE ISOLATED STRONG CONVECTION NOTED FROM 09N TO 14.5N 
BETWEEN 120W AND 126W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION NOTED WITHIN 60 NM N AND 150 NM S OF TROUGH BETWEEN 
129W AND 138W.

...DISCUSSION... 
WATER VAPOR IMAGERY SHOWS AN ELONGATED UPPER LEVEL ANTICYCLONE 
NEAR 21.5N125W WITH A RIDGE STRETCHING SW TO 10N140W...AND 
ANOTHER RIDGE NE TO ACROSS SRN BAJA CALIFORNIA. BROAD UPPER SW 
TO W FLOW IS SEEN N OF THE ANTICYCLONE AND ASSOCIATED RIDGES. 
THIS FEATURE IS KEEPING THE ATMOSPHERE RATHER DRY AND STABLE 
THROUGHOUT N AND NW OF A LINE FROM 26N110W TO 17N121W TO 16N130W 
TO 15N140W AS SUGGESTED BY THE MODERATE TO STRONG SUBSIDENCE 
OBSERVED ON THE WATER VAPOR IMAGERY. AT THE SURFACE...A 1021 MB 
HIGH IS ANALYZED AT 29N129W WITH A RIDGE SE TO 22N114W. A 
WEAKENING COLD FRONT HAS STALLED ACROSS THE NW CORNER OF THE 
AREA FROM 30N135W TO 29N140W WHERE IT THEN CURVES W AND NW FROM 
THERE. ONLY ISOLATED SHOWERS ARE POSSIBLE WITHIN ABOUT 30-60 NM 
OF THE FRONT. THE HIGH IS FORECAST TO DISSIPATE OVER THE NEXT 24 
HOURS AS ANOTHER HIGH OF 1021 MB N OF THE AREA AT 36N141W MOVES 
SE TO NEAR 32N138W. THE PRES GRADIENT BETWEEN THE HIGH AND THE 
MONSOON TROUGH TO THE S IS MODEST AT BEST...AND IS AIDING IN 
PRODUCING SMALL AREAS OF FRESH NE TRADES TO THE N AND NW OF TWO 
LOW PRES CENTERS EMBEDDED ALONG THE MONSOON TROUGH...BOTH 
MENTIONED ABOVE WITH CONVECTION. THESE LOWS WILL SHIFT WWD OVER 
THE NEXT FEW DAYS...WITH FRESH NE TRADES PERSISTING ACROSS THE N 
AND NW PORTIONS AS THEY SHIFT WWD. 

E OF 110W...LIGHT TO MODERATE MONSOONAL FLOW DOMINATES THE 
REGION...WITH SMALL CLUSTERS OF MODERATE CONVECTION ALONG THE 
TROUGH. A WEAK TROPICAL WAVE IS SUGGESTED BY GLOBAL MODEL OUTPUT 
AND SATELLITE IMAGERY MOVING ACROSS CENTRAL AMERICA ALONG ABOUT 
85W...AND WILL LIKELY INDUCE ADDITIONAL CONVECTION TONIGHT AND 
SUNDAY AS IT SHIFTS W 10-15 KT. 
 
$$ 
STRIPLING