727 
 WTNT44 KNHC 150233
 TCDAT4
 HURRICANE IVAN DISCUSSION NUMBER  51
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 11 PM EDT TUE SEP 14 2004
 
 OBSERVATIONS FROM AIR FORCE AND NOAA RECONNAISSANCE AIRCRAFT
 INDICATE THAT IVAN IS MAINTAINING 120 KT...CAT. 4...INTENSITY. 
 WATER VAPOR IMAGERY AND GPS DROPSONDE OBSERVATIONS FROM THE NOAA
 G-IV JET INDICATE STRONG UPPER-LEVEL OUTFLOW AS WELL.  THERE IS THE
 POSSIBILITY THAT THE HURRICANE CORE WILL PASS OVER SOME HIGHER
 HEAT CONTENT WATERS DURING THE NEXT 24 HOURS...SO SOME
 STRENGTHENING IS POSSIBLE ON WEDNESDAY.  AS THE HURRICANE NEARS THE
 COAST...A SHALLOWER LAYER OF WARM WATERS AND SOME INCREASE IN
 VERTICAL SHEAR COULD CAUSE SLIGHT WEAKENING.  HOWEVER...WE
 EMPHASIZE THAT IVAN IS EXPECTED TO BE A VERY POWERFUL AND DANGEROUS
 HURRICANE AT LANDFALL.
 
 INITIAL MOTION IS A LITTLE FASTER...NOW 340/10.  THE TRACK FORECAST
 REASONING AND NUMERICAL GUIDANCE REMAINS BASICALLY UNCHANGED FROM
 THE PREVIOUS PACKAGE.  IVAN IS BEING STEERED MAINLY BY THE FLOW ON
 THE WEST SIDE OF A MID-TROPOSPHERIC RIDGE.  THERE IS GOOD AGREEMENT
 AMONGST THE GFDL...GFS...UKMET...NOGAPS...AND GFDN MODELS ON THE
 PREDICTED TRACK FOR THE NEXT 36 HOURS.  THE CURRENT OFFICIAL
 FORECAST TRACK FOLLOWS A CONSENSUS OF THE AFOREMENTIONED 5
 DYNAMICAL MODELS...AND IS SIMILAR TO THE FORECAST FROM THE PREVIOUS
 ADVISORY.  LATE IN THE FORECAST PERIOD...GLOBAL MODEL GUIDANCE
 SUGGESTS THAT IVAN WILL NOT GET PICKED UP BY THE WESTERLIES BUT
 RATHER WILL STALL OR MOVE ERRATICALLY NEAR THE SOUTHERN
 APPALACHIANS.  SO THIS OFFICIAL FORECAST...LIKE THE PREVIOUS ONE...
 SHOWS NO MOVEMENT AT DAYS 4 AND 5.
 
 SINCE IVAN IS SO LARGE AND INTENSE...IT HAS THE POTENTIAL TO CARRY
 STRONG AND DAMAGING WINDS WELL INLAND ALONG ITS PATH.  NOTE THAT
 THE OFFICIAL FORECAST INDICATES THAT THE SYSTEM WILL STILL BE AT
 HURRICANE STRENGTH 12 HOURS AFTER LANDFALL. 
 
 FORECASTER PASCH
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      15/0300Z 25.1N  87.2W   120 KT
  12HR VT     15/1200Z 26.6N  87.8W   125 KT
  24HR VT     16/0000Z 28.6N  88.2W   125 KT
  36HR VT     16/1200Z 30.6N  88.2W   120 KT...INLAND
  48HR VT     17/0000Z 32.6N  87.6W    70 KT...INLAND
  72HR VT     18/0000Z 35.0N  85.5W    30 KT...INLAND
  96HR VT     19/0000Z 35.5N  85.0W    20 KT...INLAND
 120HR VT     20/0000Z 35.5N  85.0W    20 KT...INLAND
  
  
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