000 WTPZ45 KNHC 060311 TCDEP5 TROPICAL DEPRESSION TEN-E DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102011 800 PM PDT WED OCT 05 2011 INFRARED SATELLITE IMAGERY INDICATES THAT THE CONVECTIVE ORGANIZATION OF THE LOW PRESSURE AREA LOCATED ABOUT 600 MILES SOUTH OF MANZANILLO HAS INCREASED. A CDO-LIKE FEATURE WITH CLOUD TOP TEMPERATURES TO -90C HAS RECENTLY FORMED...WITH MICROWAVE DATA SUGGESTING THAT THE LOW-LEVEL CENTER LIES ON THE SOUTH SIDE OF IT. DVORAK CLASSIFICATIONS WERE T1.5 FROM TAFB AND SAB AT 0000 UTC BUT THIS WAS BEFORE THE CURRENT CONVECTIVE MASS DEVELOPED. BASED ON THE SUBSEQUENT INCREASE IN ORGANIZATION...ADVISORIES ARE BEING INITIATED ON THE SYSTEM AS A 30 KT TROPICAL DEPRESSION. SINCE THE DEPRESSION IS IN ITS FORMATIVE STAGE...THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 280/09. THE CYCLONE IS FORECAST TO MOVE ON A GENERAL WEST-NORTHWESTWARD TO NORTHWESTWARD COURSE FOR THE NEXT COUPLE OF DAYS TO THE SOUTH OF A MID- TO UPPER-LEVEL RIDGE CENTERED OFFSHORE OF WEST-CENTRAL MEXICO. BETWEEN 48-72 HOURS...AN UNSEASONABLY STRONG MID- TO UPPER-LEVEL TROUGH MOVING THROUGH THE SOUTHWESTERN UNITED STATES SHOULD ERODE THE RIDGE...CAUSING THE TRACK OF THE DEPRESSION TO SLOW AND TURN NORTHWARD. THE DEPRESSION IS EXPECTED TO TURN TOWARD THE NORTHEAST AFTER 72 HOURS AS IT COMES UNDER THE INFLUENCE OF A DEEP LAYER OF WESTERLY FLOW DOMINATING THE REGION. THE OFFICIAL TRACK FORECAST IS LEFT OF ALL OF THE TRACK GUIDANCE AND IS IN BEST AGREEMENT WITH A BLEND OF THE BAMS AND ECMWF MODELS. MOST OF THE GLOBAL MODELS HAVE A POOR HANDLE ON THE INITIAL MOTION AND LOCATION OF THE DEPRESSION...SO THE OFFICIAL TRACK FORECAST IS OF RATHER LOW CONFIDENCE. SHIPS AND UW-CIMSS SHEAR ANALYSES CURRENTLY DIAGNOSE MODERATE NORTH-NORTHEASTERLY SHEAR OVER THE DEPRESSION. GLOBAL MODELS INDICATE THAT SHEAR OF ABOUT THIS MAGNITUDE SHOULD CONTINUE FOR THE NEXT 48-72 HOURS...AND THE OFFICIAL FORECAST FOLLOWS THE INTENSITY CONSENSUS AIDS BY SHOWING ONLY SLOW INTENSIFICATION DURING THIS TIME. THE CYCLONE IS FORECAST TO PEAK IN STRENGTH AROUND THE POINT OF RECURVATURE AND JUST PRIOR TO ENCOUNTERING AN INCREASE IN WESTERLY VERTICAL SHEAR LATE IN THE FORECAST PERIOD. THE OFFICIAL INTENSITY FORECAST IS CLOSE TO THE MULTI-MODEL CONSENSUS BUT IS OF LOWER CONFIDENCE THAN NORMAL GIVEN THE HIGH DEGREE OF UNCERTAINTY REGARDING THE TRACK FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 10.0N 105.1W 30 KT 35 MPH 12H 06/1200Z 10.2N 106.2W 35 KT 40 MPH 24H 07/0000Z 10.6N 107.7W 40 KT 45 MPH 36H 07/1200Z 11.1N 108.7W 45 KT 50 MPH 48H 08/0000Z 11.8N 109.7W 50 KT 60 MPH 72H 09/0000Z 13.6N 110.2W 55 KT 65 MPH 96H 10/0000Z 15.6N 108.6W 55 KT 65 MPH 120H 11/0000Z 17.4N 106.3W 55 KT 65 MPH $$ FORECASTER KIMBERLAIN