ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM HURRICANE DALILA DISCUSSION NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013 200 AM PDT WED JUL 03 2013 EARLIER MICROWAVE IMAGERY SUGGESTED THAT THE CORE CONVECTION OF DALILA HAD AGAIN BECOME SOMEWHAT DISORGANIZED...POSSIBLY DUE TO SHEAR INDICATED BY CIRRUS CLOUDS MOVING INTO THE CYCLONE FROM THE EAST. HOWEVER...THE CLOUD TOP TEMPERATURES REMAIN PERSISTENTLY NEAR OR COLDER THAN -80C...AND THE SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB HAVE NOT CHANGED DURING THE PAST 12 HOURS. THE INITIAL INTENSITY THUS REMAINS 65 KT...ALTHOUGH IT IS POSSIBLE THAT THIS IS GENEROUS. THE INITIAL MOTION IS AN UNCERTAIN 225/2. THERE IS LITTLE CHANGE IN EITHER THE TRACK FORECAST PHILOSOPHY OR THE MODEL GUIDANCE SINCE THE LAST ADVISORY. A STRONG DEEP-LAYER RIDGE OVER THE WESTERN UNITED STATES SHOULD BUILD SOUTHEASTWARD DURING THE NEXT SEVERAL DAYS AS A TROPICAL DISTURBANCE SOUTH OF EASTERN MEXICO MOVES TOWARD DALILA. THIS EVOLUTION SHOULD CAUSE THE CYCLONE TO MOVE GENERALLY WEST-SOUTHWESTWARD FOR 36 HOURS OR SO...FOLLOWED BY A WESTWARD MOTION. THE GUIDANCE BECOMES QUITE DIVERSE AFTER 72 HOURS...WITH FORECAST TRACKS SPREAD BETWEEN A SOUTHWESTWARD MOTION AND A NORTHWESTWARD MOTION. THIS PORTION OF THE TRACK WILL SHOW A GENERAL WEST-NORTHWESTWARD MOTION NEAR THE CENTER OF THE GUIDANCE ENVELOPE. THE NEW FORECAST TRACK IS SIMILAR TO THE PREVIOUS TRACK. THE ECMWF...UKMET...AND CANADIAN MODELS FORECAST DALILA TO DISSIPATE COMPLETELY DURING THE NEXT 3-5 DAYS...WHILE THE GFS AND NAVGEM MODEL SHOW IT SURVIVING AS A TROPICAL CYCLONE OR LOW PRESSURE AREA FOR 5 DAYS. THE DISSIPATION SCENARIO IS SUPPORTED BY DRY AIR SEEN NEAR THE CYCLONE IN MICROWAVE DATA...WHILE THE SURVIVAL SCENARIO IS SUPPORTED BY WARM SEA SURFACE TEMPERATURES DURING THE FIRST 3 DAYS OF THE NEW FORECAST TRACK. THE INTENSITY FORECAST GOES WITH THE SURVIVAL SCENARIO...CALLING FOR DALILA TO MAINTAIN HURRICANE STRENGTH FOR 24 HOURS WITH GRADUAL WEAKENING THEREAFTER. THE INTENSITY FORECAST HAS BEEN TWEAKED SLIGHTLY TO MATCH THE INTENSITY CONSENSUS FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 03/0900Z 18.1N 107.5W 65 KT 75 MPH 12H 03/1800Z 17.8N 107.9W 65 KT 75 MPH 24H 04/0600Z 17.4N 108.7W 65 KT 75 MPH 36H 04/1800Z 17.2N 109.6W 60 KT 70 MPH 48H 05/0600Z 17.2N 110.7W 55 KT 65 MPH 72H 06/0600Z 17.5N 113.0W 50 KT 60 MPH 96H 07/0600Z 18.0N 115.0W 40 KT 45 MPH 120H 08/0600Z 18.5N 117.5W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ FORECASTER BEVEN NNNN