030 
 WTNT42 KNHC 252047
 TCDAT2
  
 TROPICAL STORM PHILIPPE DISCUSSION NUMBER   7
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL172011
 500 PM AST SUN SEP 25 2011
  
 THE APPEARANCE OF PHILIPPE ON VISIBLE IMAGERY HAS IMPROVED OVER THE
 PAST FEW HOURS. CONVECTION HAS PERSISTED ALONG A CURVED BAND
 LOCATED TO THE WEST AND SOUTH OF THE MAIN CENTER OF CIRCULATION...
 AND A CDO-LIKE CENTRAL CONVECTIVE FEATURE HAS ALSO DEVELOPED.
 DVORAK ESTIMATES OF INTENSITY HAVE INCREASED SINCE THE LAST
 ADVISORY...AND A BLEND OF THESE ESTIMATES YIELDS AN INITIAL
 INTENSITY OF 50 KT. 
 
 PHILIPPE IS MOVING TO THE NORTHWEST TOWARD A WEAKNESS IN THE
 SUBTROPICAL RIDGE.  THIS MOTION IS EXPECTED TO CONTINUE FOR THE
 NEXT COUPLE OF DAYS...AND THERE IS GOOD AGREEMENT AMONG THE MODELS
 THROUGH 48 HOURS. BEYOND THAT TIME...THE UNCERTAINTY INCREASES AS
 SOME MODELS RECURVE THE TROPICAL CYCLONE TOWARDS THE NORTHEAST...
 WHILE OTHERS ALLOW THE RIDGE TO REBUILD...RESULTING IN A MORE
 WESTWARD TRACK. THIS DISCREPANCY IS LIKELY RELATED TO THE INTENSITY
 OF PHILIPPE...AS A DEEPER AND STRONGER SYSTEM WILL LIKELY MOVE
 FARTHER NORTH...WHILE A WEAKER SYSTEM WILL BE STEERED TO THE WEST
 BY LOWER LEVEL EASTERLIES. OVERALL...THE GUIDANCE ENVELOPE HAS
 SHIFTED WESTWARD...AND THE TRACK HAS BEEN NUDGED IN THAT DIRECTION
 ACCORDINGLY.
  
 THE ENVIRONMENT AROUND PHILIPPE CONTINUES TO BE CONDUCIVE FOR
 INTENSIFICATION. THIS FAVORABLE ENVIRONMENT IS EXPECTED TO PERSIST
 FOR THE NEXT 24 TO 36 HOURS. AFTER THAT...PHILIPPE WILL BEGIN
 INTERACTING WITH AN UPPER-LEVEL TROUGH...WHICH SHOULD RESULT IN A
 SUBSTANTIAL INCREASE IN THE VERTICAL WIND SHEAR. ADDITIONALLY...
 THE CYCLONE WILL BEGIN MOVING OVER COOLER SSTS AND INTO A MORE
 STABLE ENVIRONMENT. THE OFFICIAL INTENSITY FORECAST HAS NOT CHANGED
 SUBSTANTIALLY...AND THE FORECAST STILL CALLS FOR PHILIPPE TO
 APPROACH HURRICANE INTENSITY WITHIN THE NEXT COUPLE OF DAYS.  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  25/2100Z 13.2N  31.7W   50 KT  60 MPH
  12H  26/0600Z 14.0N  33.1W   55 KT  65 MPH
  24H  26/1800Z 15.1N  34.7W   60 KT  70 MPH
  36H  27/0600Z 16.1N  35.9W   65 KT  75 MPH
  48H  27/1800Z 17.3N  36.9W   60 KT  70 MPH
  72H  28/1800Z 20.0N  38.7W   55 KT  65 MPH
  96H  29/1800Z 22.5N  39.5W   55 KT  65 MPH
 120H  30/1800Z 25.0N  39.5W   50 KT  60 MPH
  
 $$
 FORECASTER ZELINSKY/STEWART