571 
 WTNT44 KNHC 192047
 TCDAT4
 HURRICANE DEAN DISCUSSION NUMBER  27
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL042007
 500 PM EDT SUN AUG 19 2007
  
 THE RECONNAISSANCE AIRCRAFT COMPLETED ITS MISSION...FINDING PEAK
 FLIGHT-LEVEL WINDS OF 144 KT...WITH PEAK SFMR WINDS OF 121 KT.  ONE
 OF THE LAST EYEWALL DROPSONDES GAVE A SURFACE ESTIMATE OF 118 KT
 DERIVED FROM THE LOWEST 150 METERS OF THE SOUNDING.  IN SPITE OF A
 GRADUAL PRESSURE RISE...THESE DATA INDICATE THAT 125 KT IS STILL A
 GOOD INTENSITY ESTIMATE.  CONCENTRIC EYEWALLS ARE APPARENT IN
 MICROWAVE...CONVENTIONAL SATELLITE...AND AIRCRAFT DATA...WITH THE
 STRONGEST WINDS NOW ASSOCIATED WITH THE OUTER EYEWALL.  SHORT-TERM
 INTENSITY CHANGES WILL BE GOVERNED BY INNER-CORE PROCESSES THAT ARE
 DIFFICULT TO TIME...BUT OVERALL CONDITIONS IN THE WESTERN CARIBBEAN
 WOULD FAVOR FURTHER INTENSIFICATION...AND DEAN COULD VERY WELL
 BECOME A CATEGORY FIVE HURRICANE DURING THE NEXT DAY OR TWO.
  
 THE INITIAL MOTION IS 280/17. THERE IS NO MAJOR CHANGE TO THE
 FORECAST THINKING...ALTHOUGH MODEL GUIDANCE HAS BEEN TRENDING
 SOUTHWARD...WITH NEARLY ALL OF THE LARGE-SCALE MODELS BUILDING THE
 SUBTROPICAL RIDGE WESTWARD IN TANDEM WITH DEAN. THE UPPER LOW IN
 THE GULF OF MEXICO CONTINUES WESTWARD AND IS NOT EXPECTED TO BE A
 MAJOR PLAYER IN THE FUTURE TRACK OF THE HURRICANE. THE OFFICIAL
 FORECAST HAS BEEN SHIFTED A LITTLE TO THE SOUTH...BUT STILL LIES TO
 THE NORTH OF ALL THE MAJOR MODELS EXCEPT FOR THE HWRF. ALTHOUGH I
 CANNOT EXPLAIN WHY...THE DETERMINISTIC RUN OF THE GFS IS ALONG THE
 SOUTHERN END OF THE GUIDANCE ENVELOPE...WHILE THE GFS ENSEMBLE
 MEMBERS ARE ALMOST UNIFORMLY ALONG THE NORTHERN EDGE. BECAUSE MOST
 OF THE GUIDANCE MODELS LIE TO THE SOUTH OF THE OFFICIAL FORECAST...
 SOME ADDITIONAL SOUTHWARD ADJUSTMENTS TO THE TRACK ARE POSSIBLE.
   
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      19/2100Z 17.3N  76.8W   125 KT
  12HR VT     20/0600Z 17.8N  79.4W   130 KT
  24HR VT     20/1800Z 18.4N  83.0W   135 KT
  36HR VT     21/0600Z 19.0N  86.5W   140 KT
  48HR VT     21/1800Z 19.9N  90.0W    80 KT...INLAND
  72HR VT     22/1800Z 21.5N  96.5W   100 KT
  96HR VT     23/1800Z 23.0N 101.0W    35 KT...INLAND
 120HR VT     24/1800Z...DISSIPATED
  
 $$
 FORECASTER FRANKLIN/RHOME