000 AXPZ20 KNHC 101555 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI SEP 10 2010 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 1545 UTC. ...ITCZ... AXIS FROM 08N82W TO 07N87W TO 09N93W THEN RESUMES 12N98W TO 09N110W TO 12N117W TO 12N133W THEN RESUMES 12N136W TO 10N140W. SCATTERED MODERATE WITHIN 60 NM S OF AXIS E OF 86W. SCATTERED MODERATE ISOLATED STRONG WITHIN 120 NM S OF AXIS BETWEEN 92W AND 94W. SCATTERED MODERATE WITHIN 120 NM S OF AXIS BETWEEN 98W AND 100W AND WITHIN 150 NM N OF AXIS BETWEEN 99W AND 104W. SIMILAR CONVECTION IS WITHIN 60 NM OF AXIS BETWEEN 115W AND 130W. ...DISCUSSION... RATHER SHARP NEGATIVELY TILTED UPPER LEVEL TROUGH ENTERS NW CORNER OF THE DISCUSSION AREA NEAR 32N134W AND CONTINUES SSE TO A CYCLONIC CIRCULATION NEAR 16N128W. THIS NARROW TROUGH IS SITUATED BETWEEN TWO ANTICYCLONES AND RIDGE AXES. THE FIRST ANTICYCLONE IS OVER THE EXTREME PORTION OF THE DISCUSSION AREA NEAR 19N140W WITH A RIDGE EXTENDING EWD TO NEAR 21N130W. THE OTHER AND MORE EXTENSIVE ANTICYCLONE IS CENTERED ALONG THE RIO GRANDE RIVER NEAR 27N98W AND EXTENDS WWD ACROSS NORTHERN MEXICO CENTRAL BAJA CALIFORNIA TO 23N125W. THE UPPER LEVEL CYCLONE IS LIKELY TO REMAIN TRAPPED IN PLACE WHILE THE PARENT TROUGH SHIFTS MORE NE AND WEAKENS TO A SHEAR AXIS IN BETWEEN THE TWO DOMINANT ANTICYCLONES. VERY DRY AND STABLE ATMOSPHERE DUE TO MODERATE TO STRONG SUBSIDING AIR MASS COVERS THE AREA W OF A LINE FROM 30N105W TO 20N130W TO 10N140W...AND S OF THE ITCZ W OF 115W. SOUTHERN PERIPHERY OF RIDGE ADVECTING ABUNDANT MID AND UPPER LEVEL TROPICAL MOISTURE INTO ACROSS BAJA CALIFORNIA AND THE E PACIFIC N OF 20N E OF 120W. ABOVE NORMAL VERTICAL SHEAR ACROSS TROPICAL E PACIFIC CURTAILS SIGNIFICANT CONVECTION DEVELOPING ALONG SUMMERTIME MONSOONAL TROUGH. AT THE SURFACE...HIGH PRES CENTER 1026 MB WELL NW OF BASIN NEAR 43N145W HAS AN ASSOCIATED RIDGE EXTENDING SE THROUGH 30N133W TO 21N115W. A WEAK 1011 MB SURFACE LOW WAS NOTED ALONG THE ITCZ NEAR 12N135W...HOWEVER STABLE AIR MASS IN PLACE AND ADVERSE UPPER ENVIRONMENT IS LIMITING CONVECTIVE ACTIVITY AND HENCE DEVELOPMENT OF THE LOW. $$ COBB