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#44414 (Received by flhurricane at: 11:08 PM 06.Sep.2005) TCDAT1 TROPICAL DEPRESSION SIXTEEN DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT TUE SEP 06 2005 DATA FROM THE WSR-88D AT MELBOURNE SHOWS THAT TROPICAL DEPRESSION SIXTEEN HAS A CIRCULATION CENTER ELONGATED WEST-SOUTHWEST TO EAST-NORTHEAST. THE EARLIER NOAA AIRCRAFT FLIGHT FOUND MAXIMUM FLIGHT-LEVEL WINDS OF 27 KT MORE THAN 60 N MI AWAY FROM THE BROAD CENTER. BASED ON A 27 KT WIND FROM BUOY 41010 AND SATELLITE INTENSITY ESTIMATES...THE INITIAL INTENSITY IS INCREASED TO 30 KT. IT SHOULD BE NOTED THAT DURING THE LAST 30 MIN OR SO...THE MELBOURNE RADAR HINTS THAT A BETTER DEFINED INNER CORE MAY BE FORMING. THE NEXT NOAA AIRCRAFT WILL ARRIVE IN THE CYCLONE AT ABOUT 06Z TO SEE IF THAT IS THE CASE. THE INITIAL MOTION IS AN UNCERTAIN 330/3...WITH THE RADAR DATA HINTING AT A FASTER FORWARD MOTION. TRACK GUIDANCE AGREES ON A SLOW NORTHWESTWARD MOTION FOR 48 HR OR SO...THEN THERE IS SERIOUS DIVERGENCE. THE GFDL...GFDN...ECMWF...AND BAMS TURN THE CYCLONE WESTWARD ACROSS THE FLORIDA PENINSULA INTO THE GULF OF MEXICO. THE GFS...UKMET...NOGAPS...CANADIAN...AND BAMD TURN IT NORTHWARD AND EVEN NORTHEASTWARD OFFSHORE OF THE SOUTHEASTERN UNITED STATES. THE MODELS ARE SIMILAR IN THE OVERALL PATTERN...WITH THE CYCLONE BETWEEN TWO SEGMENTS OF THE SUBTROPICAL RIDGE AS A STRONG DEEP-LAYER TROUGH MOVES OFF THE U.S. EAST COAST. THE DIFFERENT TRACKS RESULT MAINLY FROM WHICH SEGMENT OF THE RIDGE WILL BE STRONGER...AND IT IS NOT APPARENT AT THIS TIME WHICH CLUSTER OF GUIDANCE WILL BE CORRECT. THEREFORE...THE FORECAST TRACK WILL SPLIT THE DIFFERENCE BETWEEN THE TWO EXTREMES AND CALL FOR A SLOW NORTHWESTWARD MOTION AFTER 72 HR. THIS IS A LOW-CONFIDENCE TRACK FORECAST. THE DEPRESSION IS EXPERIENCING SOME SOUTHERLY SHEAR WHICH IS PROBABLY SLOWING DEVELOPMENT. THIS SHEAR WILL LIKELY LET UP IN 12-24 HR AND ALLOW THE DEPRESSION TO STRENGTHEN INTO A TROPICAL STORM. THE SHIPS MODEL AND THE SPREAD BETWEEN THE BAMS AND BAMD SUGGEST THAT THE SHEAR WILL INCREASE AGAIN IN 48-72 HR...SO THE INTENSITY FORECAST WILL CALL FOR A PEAK INTENSITY OF 60 KT AT THAT TIME. THE INTENSITY FORECAST IS IN BEST AGREEMENT WITH THE SHIPS MODEL AND FAR ABOVE THE GFDL FORECAST. THE GFS AND UKMET SUGGEST THAT THE DEEP-LAYER TROUGH COULD COME CLOSE ENOUGH TO FEED COOLER AIR INTO THE CYCLONE...AND SHOULD THAT HAPPEN IT COULD THROW A MONKEY WRENCH INTO THE CYCLONE STRUCTURE AND THE INTENSITY FORECAST. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 07/0300Z 27.4N 78.5W 30 KT 12HR VT 07/1200Z 27.7N 78.8W 35 KT 24HR VT 08/0000Z 28.1N 79.3W 40 KT 36HR VT 08/1200Z 28.5N 79.7W 50 KT 48HR VT 09/0000Z 28.8N 80.0W 60 KT 72HR VT 10/0000Z 29.5N 80.5W 60 KT 96HR VT 11/0000Z 30.5N 81.5W 50 KT...INLAND 120HR VT 12/0000Z 30.5N 82.5W 30 KT...INLAND |