000
AXPZ20 KNHC 300921
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED JUL 30 2008

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0915 UTC.

...TROPICAL WAVES... 
TROPICAL WAVE ALONG 98W/99W N OF 04N MOVING W AT 15 KT.  THIS 
TROPICAL WAVE IS TRAILING A SURFACE LOW PRESSURE SYSTEM NEAR
09N101W. A SMALL UPPER LEVEL CYCLONIC CIRCULATION NW OF THE WAVE
AXIS NEAR 14N101W IS CARRYING DRY AIR THROUGH THE WAVE. THIS DRY 
AIR COUPLED WITH A LACK OF DIFFLUENCE ALOFT IS LIMITING 
CONVECTION ALONG THE WAVE AXIS ITSELF. HOWEVER...SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION CAN BE FOUND TO THE NW OF 
THE LOW PRESSURE SYSTEM WITHIN 180 NM N OF THE ITCZ BETWEEN 101W 
AND 108W. THE LOW PRESSURE IS EXPECTED TO DISSIPATE WITHIN 24 
HOURS. 

TROPICAL WAVE ALONG 126W FROM 07N-18N MOVING W AT 10 KT. THIS 
TROPICAL WAVE IS EMBEDDED IN THE ITCZ WITH SCATTERED MODERATE 
CONVECTION WITHIN 90-120 NM OF THE ITCZ BETWEEN 123W AND 128W.
A LARGE UPPER LEVEL LOW LIES TO THE NORTHEAST OF THE WAVE AND 
A WEAK UPPER LEVEL ANTICYCLONE CAN BE FOUND TO THE E OF THE 
WAVE. UPPER LEVEL DIFFLUENCE BETWEEN THESE TWO FEATURES COUPLED 
WITH DEEP TROPICAL MOISTURE ON THE SOUTHERN EDGE OF THE TROPICAL 
WAVE IS SUPPORTING THE CONVECTION AT THE MOMENT...BUT EXPECT THE 
CONVECTION TO WANE AS THE SYSTEM MOVES INTO A REGION OF LOWER 
SEA SURFACE TEMPERATURES AND INTO AREA MARKED BY STRONG UPPER
LEVEL SUBSIDENCE OVER THE NEXT FEW DAYS.
  
...ITCZ...
AXIS ALONG 06N77W TO 08N97W TO 07N107W TO 11N120W TO 10N140W. 
SCATTERED MODERATE TO STRONG FROM 03N TO 06N E OF 80W TO THE 
COAST OF COLOMBIA. SCATTERED MODERATE ISOLATED STRONG WITHIN 180 
NM EITHER SIDE OF THE AXIS BETWEEN 101W AND 115W. SCATTERED 
MODERATE WITHIN 90-120 NM EITHER SIDE OF THE AXIS W OF 124W. 

...DISCUSSION...
THE MID LEVEL RIDGE EXTENDING WEST-SOUTHWEST FROM THE DEEP 
ANTICYCLONE CENTERED OVER SOUTHERN NEW MEXICO WILL BE WEAKENED 
BY THE LARGE CYCLONIC CIRCULATION NEAR 23N120W AND ASSOCIATED 
TROUGH WHICH IS CURRENTLY PROVIDING UPPER LEVEL SUPPORT FOR A 
SURFACE TROUGH EXTENDING FROM 20N114W TO 11N119W. THE UPPER 
LEVEL ANTICYCLONE IS ALSO EXPECTED TO RETREAT E TO THE SOUTHERN 
HIGH PLAINS BY THURSDAY. THE CYCLONIC CIRCULATION IS FORECAST TO 
MOVE SLOWLY WESTWARD AND MERGE WITH THE INVERTED TROUGH THAT HAS 
PERSISTED NEAR 135W BY LATE THURSDAY. THE REMNANT LOW OF 
GENEVIEVE NEAR 17N136W IS ENCOUNTERING THIS WESTERN TROUGH AND
ASSOCIATED DRY AIR ALOFT AND IS FORECAST TO OPEN UP INTO A 
SURFACE TROUGH WITHIN 24 HOURS. 

AN INCREASE IN THE AVAILABLE ATMOSPHERIC MOISTURE COUPLED WITH 
UPPER LEVEL DIFLUENT EASTERLY FLOW ALOFT ALONG THE SOUTHERN 
PERIPHERY OF THE SW U.S. ANTICYCLONE AIDED IN THE DEVELOPMENT OF 
CONVECTION TONIGHT. THE STEERING FLOW HAS PUSHED SOME OF THIS 
CONVECTION OFFSHORE OF THE MEXICAN COAST BETWEEN PUERTO ANGEL
AND MANZANILLO. 

$$
COBB