751 
 WTNT44 KNHC 140839
 TCDAT4
 HURRICANE IVAN DISCUSSION NUMBER  48
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 5 AM EDT TUE SEP 14 2004
  
 A RECONNAISSANCE PLANE JUST WENT THROUGH THE EYE OF IVAN AND
 MEASURED A PRESSURE OF 924 MB WITH A DROP AND ESTIMATED 920 MB BY
 EXTRAPOLATION. MAX FLIGHT LEVEL WINDS SO FAR ARE 142 KNOTS AND WITH
 THE PRESSURE RISING...THE INITIAL INTENSITY MAY BE LITTLE LOWER. 
 BECAUSE THE PLANE HAS NOT SAMPLED THE ENTIRE CIRCULATION YET...WE
 WILL KEEP THE WINDS AT 140 KNOTS AT THIS TIME. SATELLITE IMAGES
 CONTINUE TO SHOW A WELL-DEFINED EYE SURROUNDED BY VERY COLD
 CONVECTIVE TOPS. SOME WEAKENING IS FORECAST AS IVAN MOVES FARTHER
 NORTH OVER THE EASTERN GULF OF MEXICO DURING THE NEXT COUPLE OF
 DAYS...AND ENCOUNTERS SOME WESTERLY SHEAR. HOWEVER...IVAN SHOULD
 STILL BE A MAJOR HURRICANE WHEN IT REACHES THE UNITED STATES COAST.
  
 IVAN IS MOVING TOWARD THE NORTHWEST OR 320 DEGREES AT 8 KNOTS. THERE
 HAS BEEN NO SIGNIFICANT CHANGE IN THE STEERING WHICH CONTINUES TO
 BE CONTROLLED BY A SUBTROPICAL RIDGE CENTERED OVER THE WESTERN
 ATLANTIC. IVAN IS FORECAST TO GRADUALLY TURN NORTHWARD AROUND THE
 PERIPHERY OF THE SUBTROPICAL RIDGE WITH NO SIGNIFICANT CHANGE IN
 SPEED BEFORE LANDFALL. THIS IS CONSISTENT WITH GUIDANCE WHICH
 BRINGS THE HURRICANE NEAR THE NORTH CENTRAL GULF COAST IN ABOUT 48
 HOURS. ONCE INLAND...THE GUIDANCE SLOWS DOWN A WEAKENED IVAN OVER
 THE SOUTHEASTERN UNITED STATES. THIS COULD PRODUCE ANOTHER
 SIGNIFICANT RAIN EVENT IN THAT AREA.
  
 NOTE: DUE TO FORECAST ERRORS...ONE SHOULD NOT FOCUS ON THE EXACT
 TRACK AS THE EVENTUAL LANDFALL POINT. THE ENTIRE HURRICANE WATCH
 AREA IS AT RISK.
  
 FORECASTER AVILA
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      14/0900Z 22.6N  86.0W   140 KT
  12HR VT     14/1800Z 24.0N  86.6W   140 KT
  24HR VT     15/0600Z 26.0N  87.7W   135 KT
  36HR VT     15/1800Z 28.0N  88.3W   130 KT
  48HR VT     16/0600Z 30.0N  88.0W   120 KT
  72HR VT     17/0600Z 33.5N  86.5W    50 KT...INLAND
  96HR VT     18/0600Z 35.5N  84.5W    20 KT...INLAND
 120HR VT     19/0600Z 37.0N  82.0W    20 KT...INLAND
  
  
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