000
AXPZ20 KNHC 291617
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE JUL 29 2008

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...TROPICAL WAVES... 
TROPICAL WAVE ALONG 94N N OF 05N MOVING W AT 15 KT.  WEAK UPPER 
LEVEL TROUGH FROM WRN CARIBBEAN TO BASE OF AXIS BRINGS DRY AIR 
THROUGH WAVE DECREASING CONVECTION AND ARRESTING CHANCES OF 
ORGANIZATION.  ADVERSE ENVIRONMENT ALOFT SHOULD CONTINUE FOR 
NEXT 24-36 HR AFTER WHICH WAVE ENTERS MORE FAVORABLE LOW LEVEL 
CONDITIONS AND LESS ADVERSE SHEAR ALOFT. 

SECOND TROPICAL WAVE ALONG 119W FROM 06N-20N MOVING W AT 12 KT
HAS 1011 MB LOW PRES EMBEDDED IN THE ITCZ WITH SCATTERED 
MODERATE CONVECTION WITHIN 240 NM S OF ITCZ FROM 114W-123W.
UPPER LEVEL CONFLUENT FLOW N OF 14N CURTAILS DEEP CONVECTION ON 
NRN HALF OF WAVE...BUT A MORE FAVORABLE LESSENED SHEAR ON SRN 
HALF AND ABUNDANT MOISTURE ENHANCES CONVECTION HERE.  UPPER 
ENVIRON MOVES W IN SYNC WITH WAVE...BUT IS EVENTUALLY STOPPED 
BY BLOCKING RIDGE NOW ALONG 131W.  WAVE HEADS FOR A MORE STABLE 
COOLER AND DRIER AIR MASS WHICH SHOULD ARREST ANY FURTHER 
DEVELOPMENT.
  
...ITCZ...
AXIS ALONG 08N78W TO 07N92W TO 07N100W TO 15N112W TO 09N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 240 NM OF 
AXIS FROM 113W-127W AND WITHIN 60 NM N AND 120 NM S OF AXIS FROM 
78W-93W.

...DISCUSSION...
WRN DRIFT OF UPPER LEVEL CYCLONE NOW AT 20N119W FORCING RIDGE 
RETREAT REDUCES DRY AIR MASS REGION TO W OF 126W N OF 11N...AT 
LEAST FOR THE TIME BEING.  RIDGE IS REINFORCED BY ANTICYCLONE 
DROPPING SE WHICH SHOULD STOP RETREAT AND REVERSE IT WELL 
OUTSIDE FORECAST PERIOD...DECOUPLING UPPER SUPPORT AWAY FROM 
SURFACE TROPICAL WAVE.    

ELSEWHERE AT THE SURFACE...
SURFACE LOW PRES 1011 MB AT 09N98W EMBEDDED IN ITCZ WITH LIMITED 
MODERATE CONVECTION DUE TO WIND SHEAR ALOFT.  SYSTEM EXPECTED TO 
DISSIPATE WITHIN 24 HR. 

$$
WALLY BARNES