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| #42743 (Received by flhurricane at: 5:11 AM 29.Aug.2005) TCDAT2 HURRICANE KATRINA DISCUSSION NUMBER 26 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT MON AUG 29 2005 AIR FORCE RECON HAS BEEN INVESTIGATING KATRINA THIS MORNING AND HAS REPORTED SOME MECHANICAL PROBLEMS WHICH HAS PREVENTED MAKING A COMPLETE ASSESSMENT OF THE INTENSITY IN THE NORTHEAST QUADRANT. HOWEVER...FLIGHT-LEVEL WINDS OF 132-134 KT HAVE BEEN REPORTED IN THE SOUTHEAST QUADRANT...WHILE NOAA DOPPLER RADAR VELOCITIES FROM WFO SLIDELL EXCEEDING 123 KT HAVE BEEN OBSERVED IN THE NORTHEAST QUADRANT BETWEEN 12000-16000 FT. THESE WIND VALUES WOULD SUPPORT AT LEAST 125 KT SURFACE WINDS. ALTHOUGH THE CENTRAL PRESSURE HAS CONTINUED TO INCREASE AND IS NOW 915 MB...THIS WOULD USUALLY SUPPORT ABOUT 145 KT SURFACE. THE INITIAL INTENSITY OF 130 KT IS A BLEND OF THESE VALUES. THE INITIAL MOTION IS 360/13. KATRINA IS MOVING NORTHWARD AROUND THE WESTERN PERIPHERY OF A LARGE-SCALE MID- TO UPPER-LEVEL RIDGE LOCATED OVER THE FLORIDA PENINSULA AND EXTENDING NORTHWESTWARD ACROSS THE SOUTHEASTERN UNITED STATES. THE COMBINATION OF THE STRONG RIDGE AND AN APPROACHING MID-LEVEL TROUGH FROM THE WEST SHOULD ACT TO KEEP KATRINA MOVING GENERALLY NORTHWARD FOR THE NEXT 12 HOURS OR SO. BY 24 HOURS...THE HURRICANE IS EXPECTED TO TURN NORTHEASTWARD AS A STRONGER TROUGH LIFTS OUT THE SYSTEM AND TRANSITIONS IT INTO AN EXTRATROPICAL LOW OVER THE GREAT LAKES REGION. THE OFFICIAL FORECAST TRACK IS JUST A LITTLE TO THE LEFT OF THE PREVIOUS TRACK AND IS SIMILAR TO THE NHC MODEL CONSENSUS. SOME FLUCTUATIONS IN INTENSITY ARE POSSIBLE RIGHT UP UNTIL LANDFALL OCCURS. HOWEVER...IT APPEARS THAT KATRINA WILL MAKE LANDFALL AS A CATEGORY 4 HURRICANE LATER THIS MORNING. THE CLOUD PATTERN IN SATELLITE IMAGERY HAS ERODED ON THE WEST SIDE DUE TO DRY AIR ENTRAINMENT...AND THE EYEWALL HAS OPENED UP TO THE SOUTH AND SOUTHWEST IN RADAR IMAGERY. HOWEVER...THE WATER REMAINS QUITE WARM UNDERNEATH THE CENTER...AND CONVECTION CAN EASILY REDEVELOP AND THE EYEWALL CLOSE OFF AGAIN BEFORE LANDFALL OCCURS. SOME DISRUPTION OF THE CIRCULATION WILL OCCUR ONCE THE CENTER MOVES OVER SOUTHEASTERN LOUISIANA. HOWEVER...THE FORECAST TRACK KEEPS THE EYE CLOSE ENOUGH TO WARM WATER NEAR THE LOUISIANA AND MISSISSIPPI COASTS. THE UPPER-LEVEL OUTFLOW PATTERN REMAINS QUITE IMPRESSIVE AND EVEN CONTAINS A RARE 200 MB INDRAFT ANTICYCLONE TO THE EAST NEAR TAMPA BAY. THE COMBINATION OF THE OUTFLOW REGIME AND THE CLOSE PROXIMITY TO WARM WATER MAY BE ENOUGH TO KEEP KATRINA A MAJOR HURRICANE WHEN IT REACHES THE LOUISIANA-MISSISSIPPI BORDER AREA THIS AFTERNOON. JUST BECAUSE KATRINA IS NO LONGER A CATGEORY 5 HURRICANE DOES NOT MEAN THAT EXTENSIVE DAMAGE AND STORM SURGE FLOODING WILL NOT OCCUR. THIS IS STILL AN EXTREMELY DANGEROUS AND POTENTIALLY DEADLY HURRICANE! FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 29/0900Z 28.8N 89.6W 130 KT 12HR VT 29/1800Z 30.6N 89.6W 110 KT...INLAND 24HR VT 30/0600Z 33.6N 89.0W 60 KT...INLAND 36HR VT 30/1800Z 36.7N 87.2W 35 KT...INLAND 48HR VT 31/0600Z 39.8N 84.1W 30 KT...INLAND 72HR VT 01/0600Z 45.5N 76.5W 25 KT...INLAND EXTRATROPICAL 96HR VT 02/0600Z 51.0N 68.0W 25 KT...INLAND EXTRATROPICAL 120HR VT 03/0600Z...DISSIPATED INLAND |
