000
AXPZ20 KNHC 290326
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE JUL 29 2008

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.


...TROPICAL WAVES... 
TROPICAL WAVE ALONG 90W N OF 05N MOVING W AT 15 KT. CONVECTION 
IS STRONGEST ALONG THE S EDGE OF THIS TROPICAL WAVE WHERE BOTH 
DEEP TROPICAL MOISTURE AND STRONG UPPER LEVEL DIFFLUENCE BETWEEN 
THE UPPER LEVEL RIDGE AXIS INTENSIFYING OVER THE SW CARIBBEAN 
AND THE CYCLONIC FLOW ALONG THE COAST OF NW SOUTH AMERICA CAN BE 
FOUND.  THIS TROPICAL WAVE IS EMBEDDED IN THE ITCZ WITH NUMEROUS 
MODERATE TO ISOLATED STRONG CONVECTION FOUND WITHIN 300 NM OF S 
OF THE ITCZ FROM 87W TO 92W AND WITHIN 150 NM S OF THE ITCZ 
BETWEEN THE COSTA RICAN COAST AND 87W. THE CENTRAL PORTION OF 
THIS TROPICAL WAVE LIES IN A REGION WITH LOW PRECIPITABLE WATER 
VALUES AND UPPER LEVEL CONFLUENCE BETWEEN THE RIDGE OVER THE SW 
CARIBBEAN AND A CYCLONE OVER JAMAICA AND...AS A RESULT...REMAINS 
RELATIVELY DEVOID OF CONVECTION.

FARTHER W...THERE IS A SECOND TROPICAL WAVE ALONG 116W BETWEEN 
06N AND 20N MOVING W AT 12 KT.  THIS TROPICAL WAVE IS ALSO 
EMBEDDED IN THE ITCZ WITH SCATTERED MODERATE CONVECTION WITHIN 
210 NM OF THE ITCZ BETWEEN 111W AND 123W. THIS WAVE SHOULD MOVE 
INTO A REGION OF LOWER SEA SURFACE TEMPERATURES OVER THE NEXT 
DAY OR TWO.  THIS SHOULD LIMIT THE AVAILABLE ATMOSPHERIC 
MOISTURE...HENCE THE CONVECTION...WITH THE SYSTEM.

  
...ITCZ...

THE ITCZ AXIS LIES ALONG 11N86W TO 06N102W TO 13N113W TO 10N128W 
TO 07N140W.  NUMEROUS MODERATE TO ISOLATED STRONG CONVECTION CAN 
BE FOUND WITHIN 300 NM S OF THE ITCZ FROM 87W TO 92W AND WITHIN 
150 NM S OF THE ITCZ BETWEEN THE COSTA RICAN COAST AND 87W. 
ISOLATED MODERATE CONVECTION LIES WITHIN 90 NM BETWEEN 96W AND 
99W.  SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 210 NM 
OF THE ITCZ BETWEEN 111W AND 123W.  SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION LIES WITHIN 120 NM OF THE ITCZ W OF 
136W.


...DISCUSSION...
THE MID TO UPPER LEVEL RIDGE EXTENDING FROM THE ANTICYCLONE 
FOUND ALONG THE MEXICO SW CONUS BORDER WILL EXPAND TO THE SW 
OVER THE NEXT FEW DAYS.  THE BUILDING RIDGE WILL PUSH THE 
TROPICAL WAVE CURRENTLY ALONG 116W WEST-NORTHWEST TOWARD COOLER 
WATER AS WELL AS TOWARD THE WEAK INVERTED MID LEVEL TROUGH THAT 
HAS PERSISTED NEAR 135W.  EXPECT CONVECTION TO DIMINISH OVER THE 
NEXT DAY OR SO AS A RESULT.  FARTHER TO THE NORTHEAST...THE 
REMNANT OF GENEVIEVE SHOULD ALSO BE INFLUENCED BY THIS INVERTED 
TROUGH...WITH THE SYSTEM EXPECTED TO LOSE ITS CLOSED SURFACE 
CIRCULATION OVER THE NEXT TWO DAYS AS IT ENCOUNTERS MORE 
VERTICAL SHEAR.

A SURFACE LOW PRESSURE SYSTEM CURRENTLY 1010 MB NEAR 08N96W IS 
EMBEDDED WITHIN THE ITCZ AND SUPPORTS ONLY ISOLATED MODERATE 
CONVECTION WITHIN 90 NM OF THE ITCZ BETWEEN 96W AND 99W.  THIS 
LOW PRESSURE SYSTEM IS EXPECTED TO PERSIST FOR A DAY OR TWO AS 
IT MOVES W AROUND 10-14 KT BEFORE WEAKENING AS A REGION OF UPPER 
LEVEL CONFLUENCE PASSES OVER THE SYSTEM LIMITING CONVECTION.

RELATIVELY DRY CONDITIONS AND WEAK UPPER LEVEL CONFLUENCE IS 
LIMITING CONVECTION OVER MUCH OF MEXICO AND NORTHERN CENTRAL 
AMERICA THIS EVENING.  SOME SCATTERED MODERATE TO ISOLATED 
STRONG CONVECTION FIRED ALONG THE SIERRA MADRE OCCIDENTAL AS 
WELL AS ALONG 98W BETWEEN 17N AND 21N BUT LITTLE SEEMS TO BE 
SURVIVING LONG ENOUGH TO MAKE IT TO THE COAST UNDER WEAK E 
STEERING FLOW.  THE ONLY EXCEPTION MAY BE THE COMPLEX PUSHING 
THROUGH SW GUERRERO WHICH APPEARS TO BE ORGANIZED ENOUGH TO 
POSSIBLY IMPACT THE COAST BETWEEN 98W AND 101W...INCLUDING 
ACAPULCO...OVERNIGHT.

$$
SCHAUER CLARK