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| #43482 (Received by flhurricane at: 4:34 AM 01.Sep.2005) TCDAT3 TROPICAL DEPRESSION LEE DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT THU SEP 01 2005 A REVIEW OF MICROWAVE DATA STARTING AT ABOUT 31/1720Z SUGGESTS THAT THE LOW-LEVEL CENTER OF LEE MOVED NORTHWARD BETWEEN 31/1800Z- 01/0000Z AND NORTHWESTWARD SINCE THEN...AND DID NOT FOLLOW THE CONVECTION NORTHEASTWARD ACROSS 50W. AT THE MOMENT...A WELL-DEFINED SWIRL OF LOW CLOUDS EXISTS ABOUT 90 N MI W OF THE STRONGEST CONVECTION...AND WELL TO THE WEST OF THE PREVIOUS ADVISORY POSITION. THUS...THE INITIAL POSITION IS A CONSIDERABLE RE-LOCATION FROM THE PREVIOUS ADVISORY. WHILE SATELLITE INTENSITY ESTIMATES ARE WEAKENING...THE INITIAL INTENSITY REMAINS 30 KT BASED ON A 29 KT WIND REPORTED BY SHIP ELTZ7. THE INITIAL MOTION IS AN UNCERTAIN 310/10. THE CENTER OF LEE APPEARS TO HAVE MADE A PARTIAL LOOP AS IT MERGES WITH A BROAD NON-TROPICAL LOW PRESSURE AREA THAT WAS FORMING TO ITS NORTH. MOST LARGE-SCALE MODELS HAD A POOR INITIALIZATION OF THE CYCLONE...WITH THE CENTER TOO FAR EAST AND A FORECAST TRACK TOWARD THE NORTHEAST. THE CANADIAN MODEL HAD THE BEST INITIALIZATION AND DRIFTS LEE NORTHWARD FOR THE NEXT 72 HR. THE VARIOUS BAM MODELS CONTINUE THE NORTHWESTWARD MOTION FOR 24 HR AND THEN TURN LEE NORTHWARD. THE NEW FORECAST TRACK IS A CONSIDERABLE CHANGE FROM THE PREVIOUS TRACK BASED ON THE INITIAL POSITION AND MOTION... CALLING FOR A SLOW NORTHWARD MOTION IN BEST AGREEMENT WITH THE CANADIAN MODEL. THERE IS A POSSIBILITY OF SOME ERRATIC LOOPING MOTION DURING THE FIRST 12 HR OR SO AS LEE AND THE OTHER LOW FINISH THEIR MERGER. THE MERGER OF LEE AND THE NON-TROPICAL LOW CALLS INTO QUESTION HOW TROPICAL LEE ACTUALLY IS...ESPECIALLY SINCE WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL LOW AND ASSOCIATED DRY AIR JUST WEST OF THE SURFACE CENTER. NEITHER THE GFDL OR SHIPS MODEL CALLS FOR STRENGTHENING FOR 96 HR...AND THE CANADIAN BREAKS THE CIRCULATION OPEN INTO A TROUGH AFTER 72 HR. THE NEW INTENSITY FORECAST WILL BE THE SAME AS THE PREVIOUS ADVISORY ON THE PREMISE THAT CONVECTION COULD RE-FORM FOR A TIME NEAR THE SURFACE CENTER. HOWEVER...IF THIS DOES NOT OCCUR...LEE COULD BE DOWNGRADED TO A REMNANT LOW OR TO EXTRATROPCIAL STATUS WITH 24 HR. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 01/0900Z 31.9N 51.3W 30 KT 12HR VT 01/1800Z 32.7N 51.4W 30 KT 24HR VT 02/0600Z 33.4N 51.6W 30 KT 36HR VT 02/1800Z 34.6N 51.6W 30 KT 48HR VT 03/0600Z 35.8N 51.6W 25 KT 72HR VT 04/0600Z 38.0N 51.0W 25 KT...DISSIPATING 96HR VT 05/0600Z...DISSIPATED |
