133 
 WTNT45 KNHC 281441
 TCDAT5
 TROPICAL STORM DANNY DISCUSSION NUMBER   9
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
 1100 AM EDT FRI AUG 28 2009
  
 THE CENTER OF DANNY REMAINS EXPOSED THIS MORNING...AND OVER THE PAST
 COUPLE OF HOURS HAS BEEN MOVING ALMOST DUE WESTWARD AWAY FROM THE
 DEEP CONVECTION. NOAA BUOY 41047 WELL SOUTHEAST OF THE CENTER
 REPORTED A 1-MINUTE PEAK SUSTAINED WIND OF 31 KT AT 1100 UTC. THE
 INITIAL INTENSITY IS HELD AT 35 KT...ASSUMING THAT HIGHER WINDS
 STILL EXIST WELL EAST OF THE CENTER. AN AIR FORCE RESERVE HURRICANE
 HUNTER AIRCRAFT WILL BE INVESTIGATING DANNY LATER THIS AFTERNOON TO
 PROVIDE MORE INFORMATION ON ITS INTENSITY AND STRUCTURE.
  
 THE INITIAL MOTION ESTIMATE IS 325/9...A COMPROMISE BETWEEN THE
 SHORT TERM WESTWARD MOTION AND THE LONGER TERM NORTH-NORTHWESTWARD
 MOTION OBSERVED OVERNIGHT. THE FORECAST IS ADJUSTED TOWARD THE WEST
 DUE TO THE INITIAL MOTION AND ACTUALLY LIES WEST OF ALL THE
 DYNAMICAL MODELS AT 12 HOURS...AS THESE MODELS IMMEDIATELY TURN
 DANNY NORTHWARD. LATER IN THE FORECAST PERIOD...THE TRACK IS
 VERY CLOSE TO THE TVCN MULTI-MODEL CONSENSUS. BY 36 HOURS...THIS
 POSITION IS JUST SOUTH OF THE COAST OF MASSACHUSETTS...WITH THE
 GFS...ECMWF...AND GFS ENSEMBLE MEAN SIGNIFICANTLY LEFT OF THE
 CONSENSUS...AND MOST OF THE OTHER GUIDANCE CLUSTERED TO THE RIGHT.
 BEYOND THAT TIME...DANNY SHOULD BE ACCELERATING TOWARD THE
 NORTHEAST THROUGH THE CANADIAN MARITIMES AND EAST-NORTHEASTWARD
 INTO THE NORTH ATLANTIC.
  
 IT SHOULD BE NOTED THAT THERE ARE A COUPLE OF ALTERNATIVE SCENARIOS
 THAT COULD OCCUR. THE SHALLOW BAM MODEL REPRESENTS AN EVEN MORE
 WESTWARD TRACK THAT COULD OCCUR IF DANNY LOSES ALL OF ITS DEEP
 CONVECTION. IT IS ALSO POSSIBLE THAT A NEW CENTER COULD RE-FORM
 UNDER THE DEEP CONVECTION FARTHER EAST. EITHER OF THESE SCENARIOS
 WOULD LIKELY REDUCE THE THREAT TO THE U.S. EAST COAST. 
  
 THE INTENSITY FORECAST SHOWS THE POSSIBILITY FOR A LITTLE
 STRENGTHENING IN THE NEXT 12 HOURS...BUT AFTER THAT TIME THE
 CYCLONE WILL BE MOVING INTO A VERY UNFAVORABLE ENVIRONMENT...WITH
 THE SHIPS MODEL SHOWING WIND SHEAR INCREASING TO OVER 30 KT BY 24
 HOURS AS DANNY INTERACTS WITH A DEEP-LAYER TROUGH OVER THE EASTERN
 UNITED STATES. THE GLOBAL MODELS AND PHASE SPACE DIAGRAMS SHOW THAT
 DANNY WILL BEGIN EXTRATROPICAL TRANSITION BEGINNING BY 48
 HOURS...AND THAT THE CYCLONE WILL BE FULLY EXTRATROPICAL BY 72
 HOURS. THIS EVOLUTION IS REFLECTED IN THE OFFICIAL FORECAST...WHICH
 SHOWS AN EXPANDING WIND FIELD AS DANNY MOVES FROM THE CANADIAN
 MARITIMES INTO THE NORTH ATLANTIC.
  
 DESPITE THE WESTWARD SHIFT IN THE TRACK...A TROPICAL STORM WARNING
 WILL NOT BE ISSUED FOR THE COAST OF NORTH CAROLINA AT THIS
 TIME...DUE TO THE CURRENT AND EXPECTED LIMITED EXTENT OF TROPICAL
 STORM FORCE WINDS ON THE WEST SIDE OF THE CIRCULATION. THE TROPICAL
 STORM WATCH REMAINS IN EFFECT IN CASE THE WIND FIELD BECOMES BETTER
 DEFINED ON THE WESTERN SIDE OF DANNY OR IF THE FORECAST CONTINUES
 TO SHIFT WESTWARD. A TROPICAL STORM WATCH MAY ALSO BE NEEDED FOR
 PORTIONS OF THE COAST OF NEW ENGLAND LATER TODAY.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      28/1500Z 30.1N  75.5W    35 KT
  12HR VT     29/0000Z 32.5N  75.7W    40 KT
  24HR VT     29/1200Z 36.2N  74.1W    40 KT
  36HR VT     30/0000Z 40.7N  70.7W    40 KT
  48HR VT     30/1200Z 44.6N  65.1W    40 KT...INLAND
  72HR VT     31/1200Z 49.6N  52.5W    40 KT...EXTRATROPICAL
  96HR VT     01/1200Z 52.5N  38.0W    40 KT...EXTRATROPICAL
 120HR VT     02/1200Z 54.5N  21.5W    45 KT...EXTRATROPICAL
  
 $$
 FORECASTER BRENNAN