000 AXPZ20 KNHC 300949 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE JUL 30 2013 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURE... A 1009 MB LOW PRESSURE IS CENTERED NEAR 11N112.5W AND IS MOVING W AT 11 KT ALONG THE SOUTHERN PERIPHERY OF A UPPER ANTICYCLONE. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 90 NM EITHER SIDE OF A LINE FROM 15N116W TO 11N113W TO 09.5N109W. THIS LOW MAY DEVELOP INTO A TROPICAL CYCLONE AS IT MOVES TO NEAR 14N116W LATE TONIGHT AND NEAR 15N119W ON WED NIGHT. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS E TO W FROM THE NW COAST OF COLOMBIA AT 09N77W TO ACROSS THE PANAMA/COSTA RICA BORDER TO THE COAST OF COSTA RICA AT 10N85W...THEN CONTINUES WNW TO THE EMBEDDED LOW PRESSURE AT 11N112.5W...THEN SW TO 10N120W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN INTERTROPICAL CONVERGENCE ZONE WHICH CONTINUES NW TO 12N133W...THEN TURNS SW TO BEYOND 10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED ALONG THE COAST OF COLOMBIA FROM 04-08N E OF 80W...WITHIN 90 NM EITHER SIDE OF A LINE FROM 07N96W TO 11N101W TO 12N107W...FROM 10N TO 15N BETWEEN 118W AND 123W...AND WITHIN 30 NM EITHER SIDE OF LINE FROM 14N130W TO 11N137W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 150 NM OF COAST OF CENTRAL AMERICA FROM 90-98W. ...DISCUSSION... THE MEAN AXIS OF A SERIES OF UPPER TROUGHS EXTENDS FROM 32N131W TO 13N130W EFFECTIVELY DIVIDING THE UPPER LEVELS OF THE DISCUSSION AREA TO THE E AND W OF 123W. VERY DRY UPPER AIR IS ADVECTED NE ACROSS THE DISCUSSION AREA WITHIN ABOUT 600 NM EITHER SIDE OF A LINE FROM 22N130W TO ACROSS SOUTHERN CALIFORNIA AND ALSO OVER THE NORTHERN PORTION OF THE BAJA CALIFORNIA PENINSULA AND THE GULF OF CALIFORNIA. A TROPICAL UPPER ANTICYCLONE IS NOTED AT 17N141W WITH AN UPPER RIDGE EXTENDING E TO 16N130W. WEAK UPPER DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF THE ASSOCIATED ANTICYCLONIC FLOW IS SUPPORTING THE CONVECTION PREVIOUSLY DESCRIBED ALONG THE WESTERN PORTION OF THE MONSOON TROUGH AND ALONG THE ITCZ...WITH THE DEBRIS MOISTURE EVAPORATING NEAR THE CLUSTERS AS THE UPPER LEVELS ARE DRY ELSEWHERE ACROSS THE TROPICS BETWEEN 130-140W. A LARGE UPPER ANTICYCLONE IS QUASI-STATIONARY OVER THE TEXAS PANHANDLE WITH ITS ENVELOPE OF ANTICYCLONIC FLOW EXTENDING S OVER THE DISCUSSION AREA TO THE N OF 21N BETWEEN 105-122W. DENSE DEBRIS MOISTURE...FROM PREVIOUS CONVECTION ALONG THE SIERRA MADRE OCCIDENTAL AND OVER N-CENTRAL OLD MEXICO THE...IS ADVECTED W ACROSS THE GULF OF CALIFORNIA AND THE BAJA PENINSULA TO THE S OF 28N. SOME OF THIS UPPER MOISTURE IS SPREADING N AND NE ACROSS SOUTHERN NEW MEXICO AND W TEXAS. A SMALL UPPER CYCLONE IS CENTERED OVER THE PACIFIC AT 17N108W AND CONTINUES TO MOVE W WITH TIME. ITS CYCLONIC CIRCULATION CONTINUES TO TAP MONSOON TROUGH DEBRIS MOISTURE AND ADVECTS IT N ACROSS THE PACIFIC TO THE N OF 11N BETWEEN 95-105W FEEDING INTO SMALL CLUSTERS OF CONVECTION OVER INTERIOR MEXICO FROM 17-21N. AN UPPER ANTICYCLONE IS OVER NICARAGUA WITH ITS ENVELOPE OF ANTICYCLONIC FLOW EXTENDING S OVER THE TROPICS TO THE N OF 04N BETWEEN 78-101W. THE ASSOCIATED UPPER DIFFLUENCE IS SUPPORTING THE CONVECTION PREVIOUSLY DESCRIBED ALONG THE E PORTION OF THE MONSOON TROUGH. INTENSE CONVECTION HAS DEVELOPED AGAIN THIS MORNING ALONG WESTERN COLOMBIA FROM 04N-11N. $$ NELSON