000 WTNT42 KNHC 282047 TCDAT2 HURRICANE KATRINA DISCUSSION NUMBER 24 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT SUN AUG 28 2005 KATRINA IS MAINTAINING A CLASSIC PRESENTATION ON SATELLITE IMAGES...AND CATEGORY 5 INTENSITY. THE CENTRAL PRESSURE MEASURED BY A NOAA HURRICANE HUNTER PLANE AT 1755Z AND 1923Z WAS 902 MB...WHICH IS THE FOURTH LOWEST ON RECORD IN THE ATLANTIC BASIN BEHIND HURRICANE GILBERT OF 1988...THE LABOR DAY HURRICANE OF 1935...AND HURRICANE ALLEN OF 1980. HAVING SAID THAT...DATA FROM THE STEPPED-FREQUENCY MICROWAVE RADIOMETER INSTRUMENT ON BOARD THE AIRCRAFT SUGGEST THAT THE SURFACE TO 700 MB FLIGHT LEVEL WIND RATIO IS NOT QUITE AS LARGE AS WE TYPICALLY USE...AND THE INITIAL INTENSITY IS ADJUSTED SLIGHTLY TO 145 KT. HURRICANES DO NOT MAINTAIN SUCH GREAT INTENSITY FOR VERY LONG. HOWEVER THERE ARE NO OBVIOUS LARGE-SCALE MECHANISMS...SUCH AS INCREASED VERTICAL SHEAR...TO WEAKEN KATRINA. THE HURRICANE IS LIKELY TO MAKE LANDFALL WITH CATEGORY 4 OR 5 INTENSITY. THERE IS NOT MUCH CHANGE TO THE TRACK FORECAST PHILOSOPHY. INITIAL MOTION IS ABOUT 315/11. KATRINA IS EXPECTED TO GRADUALLY TURN NORTHWARD INTO A BREAK IN THE SUBTROPICAL RIDGE ASSOCIATED WITH A LARGE MID-LATITUDE CYCLONE NEAR THE GREAT LAKES. THE 12Z GFDL HURRICANE MODEL'S TRACK HAS SHIFTED A LITTLE WESTWARD...AS HAS THE LATEST NOGAPS RUN. THE OFFICIAL FORECAST IS SLIGHTLY TO THE WEST AND SLIGHTLY FASTER THAN THE PREVIOUS NHC TRACK. THIS IS VERY CLOSE TO BOTH THE DYNAMICAL MODEL CONSENSUS... AND TO THE LATEST FSU SUPERENSEMBLE TRACK. AMONG OUR MOST RELIABLE MODELS...ONLY THE U.K. MET. OFFICE IS SIGNIFICANTLY TO THE EAST OF THE OFFICIAL FORECAST TRACK. IT SHOULD BE NOTED THAT THE SMALL CHANGE IN THE OFFICIAL FORECAST TRACK IS ESSENTIALLY AT THE NOISE LEVEL. ONE SHOULD NOT FOCUS ON THE EXACT TRACK...PARTICULARLY IN THE CASE OF A HURRICANE AS LARGE AS THIS ONE. DESTRUCTIVE EFFECTS WILL LIKELY BE FELT WELL AWAY FROM THE CENTER AND IT IS NOT POSSIBLE TO SPECIFY WHICH COUNTIES OR PARISHES WILL EXPERIENCE THE WORST CONDITIONS. ON THE BASIS OF AIRCRAFT FLIGHT LEVEL AND SFMR SURFACE WIND DATA...THE WIND RADII HAVE BEEN EXPANDED EVEN MORE OVER THE NORTHERN SEMICIRCLE. HURRICANE FORCE WINDS ARE FORECAST TO SPREAD AT LEAST 150 N MI INLAND ALONG THE PATH OF KATRINA. CONSULT INLAND HURRICANE AND TROPICAL STORM WARNINGS ISSUED BY NATIONAL WEATHER SERVICE FORECAST OFFICES. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 28/2100Z 26.9N 89.0W 145 KT 12HR VT 29/0600Z 28.3N 89.8W 145 KT 24HR VT 29/1800Z 30.6N 89.9W 130 KT...INLAND 36HR VT 30/0600Z 33.4N 89.2W 60 KT...INLAND 48HR VT 30/1800Z 36.0N 87.5W 35 KT...INLAND 72HR VT 31/1800Z 41.0N 81.5W 30 KT...INLAND 96HR VT 01/1800Z 48.0N 72.5W 25 KT...EXTRATROPICAL 120HR VT 02/1800Z...ABSORBED $$