517 
 WTNT44 KNHC 160252
 TCDAT4
 TROPICAL STORM DEAN DISCUSSION NUMBER  11
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL042007
 1100 PM EDT WED AUG 15 2007
  
 DEAN HAS CONTINUED TO GRADUALLY BECOME BETTER ORGANIZED THIS
 EVENING...WITH A 2311 UTC TRMM PASS SUGGESTING THAT A SMALL BANDING
 EYE FEATURE MAY BE FORMING. THE 00Z DVORAK SATELLITE INTENSITY
 ESTIMATES WERE 55 KT...HOWEVER...THE SATELLITE APPEARANCE HAS
 IMPROVED SINCE THEN AND THE ADVISORY INTENSITY HAS BEEN INCREASED
 TO 60 KT. 
 
 THE INITIAL MOTION ESTIMATE IS 280/20. DEAN IS FORECAST TO CONTINUE
 MOVING WEST TO WEST-NORTHWESTWARD SOUTH OF A DEEP-LAYER RIDGE
 LOCATED OVER THE CENTRAL ATLANTIC. THE TRACK GUIDANCE IS TIGHTLY
 CLUSTERED ON THIS MOTION DURING THE NEXT 72 HOURS. AT DAYS 4 AND
 5...THE TRACK GUIDANCE HAS A BIT MORE SPREAD...BUT STILL IS IN GOOD
 AGREEMENT ON A CONTINUED WEST-NORTHWEST MOTION INTO THE
 NORTHWESTERN CARIBBEAN SEA. THE GLOBAL MODELS SHOW VERY LITTLE
 INTERACTION BETWEEN DEAN AND A MIDDLE-LEVEL TROUGH CURRENTLY OVER
 THE BAHAMAS...AS THEY CONTINUE TO MOVE THE TROUGH WESTWARD AHEAD OF
 DEAN. THE NOGAPS IS A LITTLE SLOWER TO MOVE THE TROUGH WEST AND ITS
 TRACK IS THEREFORE A LITTLE FARTHER NORTH THAN THE REST OF THE
 GUIDANCE. THE NEW OFFICIAL TRACK FORECAST IS NEAR THE MIDDLE OF THE
 GUIDANCE ENVELOPE AND CLOSE TO THE GUNA MODEL CONSENSUS.
  
 THERE ARE SEEMINGLY FEW FACTORS THAT WOULD INHIBIT STRENGTHENING
 DURING THE FORECAST PERIOD.  AS MENTIONED IN THE PREVIOUS
 DISCUSSION...THE MODELS UNANIMOUSLY DEVELOP A LARGE UPPER-LEVEL
 ANTICYCLONE OVER DEAN AS IT MOVES INTO THE CARIBBEAN SEA.
 MYSTERIOUSLY...THE GFDL AND HWRF MODELS HAVE BACKED OFF ON THEIR
 RESPECTIVE INTENSITY FORECASTS.  HOWEVER...THE SHIPS AND LGEM
 MODELS CONTINUE TO INDICATE STEADY STRENGTHENING AND THE OFFICIAL
 INTENSITY FORECAST IS UNCHANGED FROM THE PREVIOUS ADVISORY.
 
 AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT WILL BE 
 INVESTIGATING DEAN TOMORROW AFTERNOON...AND THE NOAA GULFSTREAM-IV
 WILL CONDUCT A SYNOPTIC SURVEILLANCE MISSION FOR THE 17/00Z
 ANALYSIS CYCLE.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      16/0300Z 13.1N  50.2W    60 KT
  12HR VT     16/1200Z 13.6N  53.2W    65 KT
  24HR VT     17/0000Z 14.2N  57.2W    70 KT
  36HR VT     17/1200Z 14.8N  61.1W    75 KT
  48HR VT     18/0000Z 15.3N  64.7W    85 KT
  72HR VT     19/0000Z 16.3N  71.5W    95 KT
  96HR VT     20/0000Z 17.8N  78.5W   105 KT
 120HR VT     21/0000Z 19.5N  85.5W   115 KT
  
 $$
 FORECASTER BROWN