000 AXPZ20 KNHC 311554 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU JUL 31 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 1545 UTC. ...TROPICAL WAVES... A TROPICAL WAVE LOCATED N OF 03N ALONG 85W HAS MOVED W AT AN ESTIMATED 17 KT OVER HE PAST FEW DAYS. BROAD CYCLONIC TURNING IS NOTED ALONG THE WAVE AXIS OVER INTERIOR HONDURAS. A LARGE CLUSTER OF CONVECTION IS ENHANCED OVER THE GULF OF HONDURAS WITH SMALLER CLUSTERS NOTED ALONG THE CARIBBEAN COAST OF COSTA RICA AND NICARAGUA. ONLY SLIGHT ENHANCEMENT OF CONVECTION ALONG THE ITCZ IS NOTED WITHIN 150 NM OF 05N87W. A TROPICAL WAVE IS ANALYZED TO THE N OF 03N ALONG 105W AND HAS MOVED W AT ABOUT 12 KT OVER THE PAST 24 HOURS. A PERSISTENT CYCLONIC SWIRL IS ANALYZED ALONG THE WAVE AXIS AT 09N AND IS ACCOMPANIED BY SCATTERED MODERATE AND ISOLATED STRONG CONVECTION WITHIN ABOUT 90 NM OF 09N106W AT THE MOMENT. THIS LOW PRES IS EXPECTED TO DISSIPATE TONIGHT. ...ITCZ... THE ITCZ AXIS FLUCTUATES BETWEEN 08N AND 10N ACROSS THE E PACIFIC TO THE E OF 140W. ISOLATED MODERATE AND STRONG CLUSTERS ARE NOTED FROM 04N TO 11N TO THE E OF 130W. ...DISCUSSION... AN UPPER LEVEL TROUGH LIES ALONG THE NORTHERN PART OF THE DISCUSSION AREA WITH ITS MEAN AXIS FROM 36N135W TO AN UPPER CYCLONE AT 31N142W CONTINUING SW INTO AN UPPER CYCLONE AT NW OF HAWAII AT 25N159W. AN UPPER ANTICYCLONE IS CENTERED AT 13N143W WITH A RIDGE EXTENDING NE TO A CREST AT 26N135W. A WELL DEFINED UPPER CYCLONE IS CENTERED AT 28N123W WITH A TROUGH EXTENDING SW ALONG 20N126W TO 12N133W TO A BASE AT 04N131W. THIS LARGE CYCLONE IS NOW MOVING NW...AND IS ACCOMPANIED BY UPPER LEVEL MOISTURE WITHIN ROUGHLY 500 NM OF ITS CENTER. SOME OF THIS MOISTURE IS NOW ADVECTED N ACROSS CALIFORNIA AND ARIZONA. OTHERWISE...THE UPPER LEVELS ARE VERY DRY OVER THE DISCUSSION AREA TO THE N OF 12N AND W OF 130W...AND IS SUPPRESSING CONVECTION. THE REMNANT LOW OF FORMER TROPICAL CYCLONE GENEVIEVE IS NEAR 17N140W WITH ITS ASSOCIATED CONVECTION COMPLETELY SUPPRESSED. ADDITIONALLY...AT THE LOW LEVELS A COLD FRONT IS DISSIPATING N OF THE AREA FROM 35N145W TO 31N150W WITH A RIDGE BRIDGING ITS REMNANTS ALONG 32N143W TO 26N125W TO 15N107W. NW WINDS IN THE 15 20 KT RANGE ARE NOTED ALONG THE SW COAST OF THE BAJA PENINSULA. A TROPICAL UPPER ANTICYCLONE IS NEAR 12N126W. ASSOCIATED UPPER DIFFLUENCE IS ENHANCING CONVECTION ALONG A LOW LEVEL TROUGH THAT EXTENDS FROM 10N125W TO 20N121W WITH THE DEBRIS MOISTURE REMAINING WITHIN 150 NM EITHER SIDE OF A LINE FROM 09N128W TO 18N120W. FURTHER E...AN UPPER ANTICYCLONE IS QUASI STATIONARY OVER SOUTHERN NEW MEXICO NEAR 33N106W WITH A RIDGE EXTENDING SW ACROSS OLD MEXICO INTO THE E PACIFIC TO A GENTLE CREST NEAR 17N112W. CONVECTION CONTINUES TO BE ENHANCED UNDER THIS UPPER RIDGE...ALONG AND JUST OFFSHORE THE PACIFIC COAST OF MEXICO... WITHIN ABOUT 90 NM EITHER SIDE OF A LINE FROM 16N104W TO 21N108W. THE RESULTANT DEBRIS MOISTURE IS TRAPPED UNDER THE UPPER RIDGE...WITH SOME OF THE MOISTURE ADVECTED N ACROSS THE GULF OF CALIFORNIA AROUND THE W PERIPHERY OF ANTICYCLONE ACROSS SW ARIZONA. AN UPPER ANTICYCLONE IS NEAR 12N81W WITH ITS ENVELOPE OF ANTICYCLONIC FLOW EXTENDING W OVER THE TROPICAL PACIFIC TO THE E OF 93W...AND ENHANCING ITCZ CONVECTION AND CONVECTION ASSOCIATED WITH A TROPICAL WAVE. THE DEBRIS MOISTURE REMAINS S OF 20N BETWEEN 78W AND 90W. SEPARATING THIS ANTICYCLONE FROM THE OTHERS MENTIONED ABOVE IS THE SW EXTENSION OF AN ATLC TROPICAL UPPER TROUGH THAT EXTENDS THROUGH UPPER CYCLONES AT 21N73W AND 19N89W AND 10N98W TO A BASE AT EQUATOR AT 106W. SOUTHERLY WINDS TO 20 KT AND SOUTHERLY SWELLS TO 8 FT ARE OBSERVED OVER THE TROPICAL WATERS TO THE S OF 09N BETWEEN 92W AND 112W. ALTHOUGH THE WINDS ARE EXPECTED TO DIMINISH TO LESS THAN 20 KT...THE SOUTHERLY SWELLS ARE EXPECTED TO SPREAD E OVER THE WATERS S OF 08N BETWEEN 120W AND 83W BY SAT. $$ NELSON