000 WTPZ43 KNHC 191707 TCDEP3 TROPICAL DEPRESSION THIRTEEN-E SPECIAL DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132007 1000 AM PDT WED SEP 19 2007 EVEN THOUGH THE CLOUD TOPS ARE BEGINNING TO WARM IN INFRARED SATELLITE IMAGERY....VISIBLE IMAGERY INDICATES THAT THE AREA OF DISTURBED WEATHER SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA HAS ACQUIRED ENOUGH ORGANIZATION TO BE CLASSIFIED AS A TROPICAL DEPRESSION. THE CENTER OF THE DEPRESSION IS LOCATED WITHIN THE EASTERN PORTION OF THE CONVECTION. DATA FROM A RECENT QUIKSCAT PASS AND A DVORAK INTENSITY FROM SAB SUPPORT A 30 KT INITIAL INTENSITY. THE DEPRESSION IS MOVING SLOWLY WESTWARD SOUTH OF A MID-LEVEL RIDGE TO THE NORTH. THE RIDGE IS FORECAST TO ERODE DURING THE NEXT DAY OR SO AS A LARGE MID-TO UPPER-LEVEL TROUGH DROPS SOUTHWARD OFF THE WEST COAST OF THE UNITED STATES. THIS IS EXPECTED TO LEAVE THE DEPRESSION IN AN AREA OF WEAK STEERING CURRENTS. AFTER 48 HOURS...THE DYNAMICAL GUIDANCE SUGGEST THAT THE TROUGH WILL DIG FAR ENOUGH SOUTH TO INDUCE A NORTHEASTWARD MOTION. MUCH OF THE GUIDANCE FORECAST AN ANTICYCLONIC LOOP OF THE CYCLONE...HOWEVER THE OFFICIAL FORECAST WILL SHOW A SLOW WESTWARD MOTION...WITH A TURN TO THE NORTHEAST AFTER 48 HOURS. FUTURE INTENSIFICATION OF THE DEPRESSION LOOKS RATHER BLEAK. THE INTENSITY FORECAST ALLOWS FOR STRENGTHENING TO A MINIMAL TROPICAL STORM IN 24 HOURS...ASSUMING THAT THE CYCLONE DOES NOT INGEST TOO MUCH OF THE STABLE AIR TO THE NORTH. THEREAFTER...THE CYCLONE WILL BE MOVING OVER COOLER WATER...AND SOUTHWESTERLY SHEAR IS EXPECTED TO INCREASE BEYOND 48 HOURS...WHICH SHOULD INDUCE WEAKENING. FORECAST POSITIONS AND MAX WINDS INITIAL 19/1700Z 17.1N 127.9W 30 KT 12HR VT 20/0000Z 17.2N 128.5W 30 KT 24HR VT 20/1200Z 17.2N 129.2W 35 KT 36HR VT 21/0000Z 17.2N 129.9W 35 KT 48HR VT 21/1200Z 17.5N 129.9W 30 KT 72HR VT 22/1200Z 18.5N 128.6W 25 KT 96HR VT 23/1200Z 19.5N 127.5W 25 KT 120HR VT 24/1200Z 20.5N 126.0W 25 KT $$ FORECASTER BROWN