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#98120 (Received by flhurricane at: 11:00 AM 18.Jul.2006) TCDAT2 TROPICAL DEPRESSION TWO DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022006 1100 AM EDT TUE JUL 18 2006 CONVENTIONAL AND MICROWAVE SATELLITE DATA...ALONG WITH INFORMATION FROM SURROUNDING BUOYS...INDICATE THE LOW PRESSURE SYSTEM LOCATED ABOUT 250 NMI SOUTHEAST OF THE NORTH CAROLINA COAST HAS BECOME MUCH BETTER ORGANIZED THIS MORNING. BANDING FEATURES HAVE IMPROVED IN THE SOUTHEASTERN SEMICIRCLE WHERE AN EARLIER QUIKSCAT OVERPASS INDICATED SEVERAL 20-25 KT UNCONTAMINATED WIND VECTORS. THEREFORE...THE SYSTEM AS BEEN UPGRADED TO TROPICAL DEPRESSION TWO. THE INITIAL MOTION ESTIMATE IS A SOMEWHAT UNCERTAIN 360/04...MAINLY DUE TO SOME UNCERTAINTY IN THE EXACT LOCATION OF THE LOW-LEVEL CENTER RELATIVE TO THE DEVELOPING CONVECTIVE PATTERN. HOWEVER... LONG TERM SATELLITE LOOPS AND MICROWAVE DATA SUGGEST THAT A GENERAL SLOW NORTHWARD MOTION HAS BEEN OCCURRING FOR THE PAST 6-9 HOURS. THE DEPRESSION IS CAUGHT IN A BREAK IN THE SUBTROPICAL RIDGE WHOSE AXIS LIES ALONG ABOUT 35N LATITUDE. MOST OF THE GLOBAL MODELS HAVE KEYED ON A WEAK LOW PRESSURE SYSTEM LOCATED ABOUT 200 NMI NORTHEAST OF TD-2. THAT SYSTEM SHOWS NO SIGNS OF DEVELOPMENT. THE ONLY MODELS THAT HAVE INITIALIZED THIS SYSTEM WITH ANY REASONABLE ACCURACY DURING THE PAST 24 HOURS HAS BEEN THE NAM AND UKMET MODELS. THE 3 GFS-BASED BAM MODELS ARE ALMOST ON TOP OF EACH OTHER AND TAKE THE CYCLONE INTO NORTH CAROLINA NEAR CAPE LOOKOUT IN 36-48 HOURS. THE NAM AND UKMET MOVE THE SYSTEM OVER OR JUST EAST OF THE NORTH CAROLINA OUTER BANKS IN ABOUT 48 HOURS. THE LATTER SCENARIO IS PREFERRED AT THIS TIME DUE TO THE UNCERTAINTY IN JUST HOW FAR SOUTH AN UPPER-LOW WILL DIG THAT IS CURRENTLY SITUATED WEST-SOUTHWEST OF THE DEPRESSION. IF THE UPPER-LOW DIGS A LITTLE FARTHER SOUTH THAN FORECAST BY THE MODELS...THEN A MORE NORTHWESTWARD MOTION SIMILAR TO THE BAM MODELS COULD OCCUR. DUE TO THE THIS UNCERTAINTY...A TROPICAL STORM WATCH HAS BEEN ISSUED FOR THE EASTERN PORTIONS OF NORTH CAROLINA. THE INTENSITY FORECAST IS SOMEWHAT TRICKY. THE SHIPS MODEL ONLY BRINGS THE CYCLONE UP TO ABOUT 45 KT IN 48 HOURS. HOWEVER... THIS CONSERVATIVE INTENSITY FORECAST APPEARS TO BE DUE IN PART TO POORLY INITIALIZED SST CONDITIONS. THE SHIPS MODEL CURRENTLY INDICATES THE SYSTEM IS OVER 80F SSTS...WHEREAS SURROUNDING SHIP AND BUOY DATA INDICATE SSTS ARE 82-83F UNDER THE CORE OF THE CYCLONE. IN ADDITION...THE SHIPS MODEL INDICATES THAT UPPER-LEVEL DIVERGENCE WILL BE POOR AT BEST AND... THEREFORE... A NEGATIVE CONTRIBUTING FACTOR. IN CONTRAST...LATEST SATELLITE IMAGERY INDICATES CIRRUS OUTFLOW HAS BEEN EXPANDING TO THE NORTHWEST... WHILE AN UPPER-LEVEL LOW TO THE SOUTHEAST OF THE CYCLONE IS BEGINNING TO ENHANCE THE OUTFLOW TO THE SOUTH. GIVEN THIS FAVORABLE DEVELOPING OUTFLOW PATTERN... THE INTENSITY FORECAST IS HIGHER THAN THE SHIPS MODEL. FORECAST POSITIONS AND MAX WINDS INITIAL 18/1500Z 32.5N 73.4W 30 KT 12HR VT 19/0000Z 33.3N 73.7W 35 KT 24HR VT 19/1200Z 33.9N 74.1W 40 KT 36HR VT 20/0000Z 34.7N 74.8W 45 KT 48HR VT 20/1200Z 35.5N 75.0W 55 KT 72HR VT 21/1200Z 36.9N 74.7W 55 KT 96HR VT 22/1200Z 38.5N 71.0W 50 KT 120HR VT 23/1200Z 42.0N 63.0W 40 KT...BECOMING EXTRATROPICAL |