000
AXPZ20 KNHC 302232
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT JUL 30 2011

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.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH AXIS EXTENDS FROM 10N86W TO 1008 MB LOW PRES NEAR 
10N97W TO 13N115W TO 10N122W TO 12N130W TO 09N140W.  SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 150 NM S OF AXIS W OF 
114W.  

...DISCUSSION...
LARGE AMPLITUDE UPPER LEVEL TROUGH ENTERS REGION AT 32N131W 
DIGGING SE TO CYCLONIC VORTEX AT 26N115W.  AREA REMAINS VERY DRY 
DUE TO SUBSIDING AIR MASS N OF 16N W 0F 110W.  BROAD ANTICYCLONE 
19N120W BRINGS MODERATE NE-E WIND SHEAR OVER CONVECTION ALONG 
MONSOON TROUGH EFFECTIVELY CURTAILING ANY TROPICAL DEVELOPMENT 
FOR THE TIME BEING.  

ABUNDANT TROPICAL MOISTURE E OF 110W ENJOY A MORE FAVORABLE 
UPPER LEVEL ENVIRONMENT WITH LIGHTER E WINDS ALOFT AND A MORE 
AGGRESSIVE LOW LEVEL CONVERGING ALONG MONSOON TROUGH.  

ELSEWHERE AT THE LOWER LEVELS...

HIGH PRES CENTER 1032 MB WELL N OF AREA MOVES SE BEHIND WEAK 
SURFACE TROUGH FROM 33N137W TO 28N132W AND BRING BACK THE 
PROCESS OF TIGHTENING PRES GRADIENT AGAINST CALIFORNIA COAST 
TROUGH.  MODERATE TO FRESH NE BREEZE AFFECT EXTREME NW PORTION 
OF BASIN THROUGH SUN.  

LOW PRES CENTER AT 10N97W IS UNDER FAVORABLE UPPER LEVEL 
ENVIRONMENT AND EXPECTED TO DEVELOP TROPICAL ORGANIZATION WITHIN 
THE NEXT 18-24 HRS.

FRESH SW MONSOON BREEZE GET ABSORBED IN WIND FIELD SURROUNDING 
LOW PRES CENTER AT 10N97W WITH BUILDING SEAS UP TO 12 FT IN S 
SEMICIRCLE. DYNAMIC MODELS BRING TROPICAL CYCLONE CONDITIONS IN 
W-NW DIRECTION OVER 24-48 HOURS WITH POSSIBLE FURTHER 
INTENSIFICATION BEYOND THAT PERIOD.
   
$$
WALLY BARNES