509 
 WTPZ44 KNHC 300848
 TCDEP4
 TROPICAL STORM KEVIN DISCUSSION NUMBER   4
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP142009
 200 AM PDT SUN AUG 30 2009
  
 ALTHOUGH KEVIN HAS BEEN UNDER THE INFLUENCE OF SOME EASTERLY
 SHEAR...THE LOW-LEVEL CENTER IS NOW LOCATED JUST UNDERNEATH THE
 HEAD OF A CURVED BAND THAT WRAPS AROUND THE WESTERN SIDE OF THE
 CIRCULATION...AND THIS PATTERN IS YIELDING DVORAK ESTIMATES OF
 T3.0...45 KT...FROM TAFB AND SAB.  IN ADDITION...A 0243 UTC
 QUIKSCAT PASS SUPPORTS MAINTAINING THE INITIAL INTENSITY AT 45 KT.
  
 WITH THE HELP OF A 0045 UTC TRMM AND A 0155 UTC WINDSAT PASS...THE
 INITIAL MOTION IS ESTIMATED AT 360/6.  KEVIN LIES ON THE WESTERN
 SIDE OF A MID-LEVEL ANTICYCLONE CENTERED BETWEEN IT AND HURRICANE
 JIMENA...AND THIS IS CAUSING THE CURRENT NORTHWARD MOTION. 
 HOWEVER...THE STEERING CURRENTS ARE EXPECTED TO REMAIN LIGHT DURING
 THE NEXT SEVERAL DAYS...AND KEVIN IS FORECAST TO MOVE SLOWLY
 NORTH-NORTHEASTWARD TO NORTHEASTWARD DURING THAT TIME.  ONE
 COMPLICATING FACTOR TO THIS FORECAST IS HOW KEVIN WILL INTERACT
 WITH THE CIRCULATION OF JIMENA.  MOST OF THE GLOBAL MODELS ARE
 PLAYING A GAME OF PINBALL...PULLING KEVIN NORTHEASTWARD TOWARD
 JIMENA AND THEN PUSHING IT BACK TO THE SOUTH OR SOUTHEAST TOWARD A
 NEW AREA OF LOW PRESSURE EXPECTED TO DEVELOP FARTHER EAST.  THE
 HWRF AND CANADIAN MODELS ARE THE ONLY TWO WHICH STILL SHOW KEVIN
 TURNING NORTHWESTWARD IN RESPONSE TO A BUILDING RIDGE TO THE NORTH. 
 THE NEW OFFICIAL FORECAST IS SHIFTED A LITTLE EAST OF THE PREVIOUS
 FORECAST TOWARD THE MODEL CONSENSUS AND SHOWS VERY LITTLE MOTION BY
 DAYS 4 AND 5 DUE TO THE LARGE UNCERTAINTY.
 
 THE INTENSITY GUIDANCE SHOWS KEVIN STRENGTHENING VERY LITTLE OVER
 THE NEXT 24-48 HOURS.  KEVIN WILL REMAIN OVER SUFFICIENTLY WARM
 WATER...BUT THE SHIPS GUIDANCE INDICATES THAT SOME EASTERLY SHEAR
 WILL CONTINUE OVER THE SYSTEM FOR THE NEXT DAY OR TWO.  ALSO...BOTH
 THE GFDL AND HWRF INDICATE NO FURTHER STRENGTHENING AND STEADY
 WEAKENING OVER THE NEXT FEW DAYS.  THE OFFICIAL FORECAST ASSUMES
 THAT KEVIN WILL BE ADVERSELY AFFECTED BY HURRICANE JIMENA AND SHOWS
 SLOW WEAKENING STARTING AT 36 HOURS...BUT IT IS STILL ABOVE THE
 INTENSITY CONSENSUS.  MANY OF THE GLOBAL MODELS LOSE A COHERENT
 VORTEX BY DAYS 4 AND 5...AND IT IS POSSIBLE THAT KEVIN MAY NOT
 EXIST AS A TROPICAL CYCLONE BY THEN.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      30/0900Z 14.1N 121.9W    45 KT
  12HR VT     30/1800Z 14.7N 121.9W    50 KT
  24HR VT     31/0600Z 15.5N 121.4W    50 KT
  36HR VT     31/1800Z 16.2N 120.8W    45 KT
  48HR VT     01/0600Z 16.9N 120.2W    40 KT
  72HR VT     02/0600Z 18.3N 119.1W    40 KT
  96HR VT     03/0600Z 19.0N 118.5W    35 KT
 120HR VT     04/0600Z 19.2N 118.2W    30 KT
  
 $$
 FORECASTER BERG