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| #156993 (Received by flhurricane at: 10:46 PM 28.Oct.2007) TCDAT1 TROPICAL STORM NOEL DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL162007 1100 PM EDT SUN OCT 28 2007 NOEL HAS NOT BECOME BETTER ORGANIZED OVER THE PAST FEW HOURS ALTHOUGH IT CONTINUES TO PRODUCE STRONG CONVECTION PRIMARILY IN CLUSTERS OVER THE NORTHEASTERN PORTION OF THE CIRCULATION. SOME OF THIS CONVECTION HAS BEEN SPREADING OVER HISPANIOLA AND IS LIKELY GENERATING VERY HEAVY RAINS OVER PORTIONS OF THAT ISLAND. DVORAK INTENSITY ESTIMATES ARE 45 KT FROM TAFB AND SAB...BUT BASED ON THE EARLIER AIRCRAFT OBSERVATIONS THE CURRENT INTENSITY IS KEPT AT 50 KT. ANOTHER RECONNAISSANCE PLANE IS SCHEDULED TO INVESTIGATE NOEL AROUND 0600 UTC TO GIVE A NEW ESTIMATE OF THE STRENGTH AND POSITION OF THE TROPICAL CYCLONE. IT IS DIFFICULT TO FIX THE LOCATION OF THE CIRCULATION CENTER BASED SOLELY ON CONVENTIONAL SATELLITE IMAGERY. UTILIZING POSITION ESTIMATES FROM EARLIER SSM/I AND AMSR-E MICROWAVE IMAGERY...THE INITIAL MOTION IS A RATHER UNCERTAIN 330/4. NOEL IS APPARENTLY EMBEDDED WITHIN THE EASTERN PORTION OF A MID- TO UPPER-LEVEL CYCLONIC CIRCULATION WITH A WEAKENING SUBTROPICAL ANTICYCLONE A LITTLE FARTHER TO THE NORTH. BOTH OF THESE FEATURES ARE FORECAST TO WEAKEN AS A MID-LEVEL SHORTWAVE TROUGH APPROACHES FROM THE NORTHWEST. THIS STEERING PATTERN EVOLUTION SHOULD CAUSE NOEL TO GRADUALLY TURN NORTHWARD IN A FEW DAYS. THE DYNAMICAL MODELS ARE BASICALLY CLUSTERING INTO TWO POSSIBLE SOLUTIONS. THE GFS AND THE ECMWF SUGGEST A WEAKER CYCLONE MOVING ON A GENERALLY WEST-NORTHWESTWARD TRACK. HOWEVER...THE GFS SOLUTION LOOKS QUESTIONABLE SINCE IT SPLITS NOEL INTO TWO LOWER-TROPOSPHERIC VORTICITY MAXIMA WITHIN A DAY OR SO AND DEVELOPS A THIRD CENTER FARTHER TO THE NORTHEAST WITHIN 72 HOURS. THE OFFICIAL TRACK FORECAST IS CLOSE TO A CONSENSUS OF THE GFDL...GFDN...HWRF...U.K. MET AND NOGAPS TRACKS. THIS IS VERY SIMILAR TO OUR PREVIOUS NHC TRACK. THE UPPER-LEVEL LOW HAS BEEN IMPARTING SOME SOUTHWESTERLY SHEARING ON THE TROPICAL CYCLONE WHICH IS INHIBITING AN INCREASE IN ORGANIZATION AT THIS TIME. DYNAMICAL GUIDANCE INDICATES THAT THIS LOW WILL SOON FILL...CREATING AN UPPER-LEVEL WIND ENVIRONMENT MORE CONDUCIVE FOR STRENGTHENING. A COMPLICATING FACTOR IS HOW MUCH THE INTERACTION WITH THE MOUNTAINOUS TERRAIN OF HAITI AND EASTERN CUBA WILL DISRUPT THE CIRCULATION OF NOEL. BY DAYS 3-5...INCREASING WESTERLY SHEAR SHOULD INTERRUPT THE INTENSIFICATION PROCESS...AND BY THE END OF THE PERIOD THE SYSTEM SHOULD BE LOSING ITS TROPICAL CHARACTERISTICS AS IT INTERACTS WITH A FRONTAL ZONE. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0300Z 17.1N 72.1W 50 KT 12HR VT 29/1200Z 18.3N 73.2W 50 KT...INLAND OVER HAITI 24HR VT 30/0000Z 19.7N 74.5W 60 KT...OVER WATER 36HR VT 30/1200Z 21.0N 75.7W 55 KT...INLAND OVER CUBA 48HR VT 31/0000Z 22.4N 76.1W 55 KT...OVER WATER 72HR VT 01/0000Z 25.0N 76.0W 55 KT 96HR VT 02/0000Z 28.0N 74.5W 50 KT 120HR VT 03/0000Z 31.0N 72.0W 45 KT...EXTRATROPICAL $$ FORECASTER PASCH/ROBERTS |
