197 
 WTNT42 KNHC 281454
 TCDAT2
 HURRICANE KATRINA DISCUSSION NUMBER  23
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 11 AM EDT SUN AUG 28 2005
 
 THE AIR FORCE HURRICANE HUNTERS JUST MEASURED A 166 KT FLIGHT LEVEL
 WIND IN THE NORTHEAST EYEWALL...WHICH REQUIRES AN ADDITIONAL UPWARD
 ADJUSTMENT OF THE CURRENT INTENSITY TO 150 KT.  A DROP IN THE EYE
 GAVE A CENTRAL PRESSURE OF 907 MB.  KATRINA IS COMPARABLE IN
 INTENSITY TO HURRICANE CAMILLE OF 1969...ONLY LARGER.  GPS
 DROPSONDE DATA FROM THE NOAA G-IV MISSION EARLIER TODAY SHOWED
 KATRINA'S INTENSE CYCLONIC CIRCULATION EXTENDING THROUGH THE 200 MB
 LEVEL...WITH THE FLOW SPIRALING ANTICYLONICALLY OUTWARD IN A
 WELL-DEVELOPED UPPER-LEVEL OUTFLOW PATTERN BEYOND A COUPLE HUNDRED
 N MI FROM THE CENTER.  FLUCTUATIONS IN STRENGTH...DUE TO INTERNAL
 STRUCTURAL CHANGES...ARE LIKELY PRIOR TO LANDFALL.  HURRICANES
 RARELY SUSTAIN SUCH EXTREME WINDS FOR MUCH TIME.  HOWEVER WE SEE
 NO OBVIOUS LARGE-SCALE EFFECTS TO CAUSE A SUBSTANTIAL WEAKENING THE
 SYSTEM...AND IT IS EXPECTED THAT THE HURRICANE WILL BE OF CATEGORY
 4 OR 5 INTENSITY WHEN IT REACHES THE COAST.
  
 THERE IS NO CHANGE TO THE TRACK FORECAST.  KATRINA SHOULD GRADUALLY
 TURN TOWARD THE NORTH...INTO A WEAKNESS IN THE SUBTROPICAL RIDGE
 ASSOCIATED WITH A LARGE MID-LATITUDE CYCLONE OVER THE NORTHERN
 UNITED STATES AND SOUTHERN CANADA.  THE OFFICIAL FORECAST TRACK IS
 ABOUT IN THE MIDDLE OF THE DYNAMICAL GUIDANCE MODELS...WHICH ARE
 RATHER TIGHTLY CLUSTERED.  RECALLING THAT THE AVERAGE NHC 24-HOUR
 TRACK FORECAST ERROR IS ABOUT 80 N MI...THE ACTUAL LANDFALL POINT
 COULD STILL BE ANYWHERE FROM SOUTHEASTERN LOUISIANA TO THE
 MISSISSIPPI COAST.  ALSO...WE MUST CONTINUE TO STRESS THAT THE
 HURRICANE IS NOT JUST A POINT ON THE MAP...BECAUSE DESTRUCTIVE
 WINDS...TORRENTIAL RAINS...STORM SURGE...AND DANGEROUS WAVES EXTEND
 WELL AWAY FROM THE EYE.  IT IS IMPOSSIBLE TO SPECIFY WHICH COUNTY
 OR PARISH WILL EXPERIENCE THE WORST WEATHER.
  
 THIS ADVISORY SHOWS AN ADDITIONAL EXPANSION OF THE WIND FIELD OVER
 THE EASTERN SEMICIRCLE BASED ON AIRCRAFT AND SURFACE OBSERVATIONS.
 HURRICANE FORCE WINDS ARE FORECAST TO SPREAD AT LEAST 150 N MI
 INLAND ALONG THE PATH OF KATRINA.  CONSULT INLAND WARNINGS ISSUED
 BY NATIONAL WEATHER SERVICE FORECAST OFFICES.
  
 FORECASTER PASCH
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      28/1500Z 26.0N  88.1W   150 KT
  12HR VT     29/0000Z 27.2N  88.9W   145 KT
  24HR VT     29/1200Z 29.1N  89.6W   140 KT
  36HR VT     30/0000Z 31.4N  89.5W    85 KT...INLAND
  48HR VT     30/1200Z 34.5N  88.5W    45 KT...INLAND
  72HR VT     31/1200Z 40.0N  84.0W    30 KT...INLAND
  96HR VT     01/1200Z 45.0N  77.0W    25 KT...EXTRATROPICAL
 120HR VT     02/1200Z 52.0N  69.0W    25 KT...EXTRATROPICAL
  
  
 $$