Show Selection: |
#41619 (Received by flhurricane at: 11:03 AM 24.Aug.2005) TCDAT2 TROPICAL STORM KATRINA DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT WED AUG 24 2005 SATELLITE IMAGERY...DOPPLER RADAR DATA FROM THE BAHAMAS AND MIAMI... AND RECONNAISSANCE WIND DATA INDICATE TD-12 HAS BECOME MUCH BETTER ORGANIZED THIS MORNING AND HAS STRENGTHENED INTO TROPICAL STORM KATRINA. THE INITIAL INTENSITY OF 35 KT IS BASED ON AN 1153Z RECON 925 MB FLIGHT-LEVEL WIND REPORT OF 48 KT IN THE NORTHEAST QUADRANT ...WHICH EQUALS ABOUT 36 KT AT THE SURFACE USING A STANDARD 75 PERCENT REDUCTION FACTOR FOR THAT LEVEL. THIS INTENSITY IS ALSO SUPPORTED BY A CONSENSUS INTENSITY ESTIMATE OF T2.5/35 KT FROM ALL THREE SATELLITE AGENCIES. THE NEXT AIRCRAFT IS EXPECTED TO INVESTIGATE KATRINA THIS AFTERNOON. THE INITIAL MOTION ESTIMATE IS 330/07. KATRINA'S CENTER MAY BE DEVELOPING A LITTLE MORE TO THE NORTH OF THE PREVIOUS FIXES IN RESPONSE TO THE BURSTS OF DEEP CONVECTION THAT HAVE BEEN DEVELOPING IN THE NORTHEAST QUADRANT OF THE LARGER CIRCULATION ENVELOPE. HOWEVER...RADAR DATA SUGGESTS THAT SMALL VORTICES OR MESOCYCLONES ARE BEING GENERATED WITHIN THE CONVECTIVE BURSTS...AND THEN PROPAGATING WESTWARD ALONG THE NORTH SIDE OF LARGER CIRCULATION. THE INITIAL POSITION REMAINS ROUGHLY IN THE GEOMETRIC CENTER OF ALL THE SMALL VORTICES NOTED IN RADAR DATA. OVERALL...RECON DATA INDICATE THE WIND FIELD CONTINUES TO CONSOLIDATE. THE FORECAST TRACK REMAINS BASICALLY UNCHANGED FORM THE PREVIOUS ADVISORIES. THE SUBTROPICAL RIDGE TO THE NORTH OF KATRINA THAT CURRENTLY EXTENDS EAST-WEST ALONG 30-31N LATITUDE IS EXPECTED TO SLOWLY BUILD EASTWARD...CAUSING THE CYCLONE TO TURN MORE WESTWARD AFTER 24 HOURS AND CROSS THE SOUTHERN FLORIDA PENINSULA. AFTER EMERGING OVER THE EASTERN GULF OF MEXICO IN 72 HOURS...THE WESTERN PORTION OF THE RIDGE IS FORECAST TO WEAKEN AND ALLOW KATRINA TO MOVE NORTHWESTWARD. KATRINA HAS DEVELOPED A SYMMETRICAL UPPER-LEVEL OUTFLOW PATTERN WITHIN A RELATIVELY WEAK SHEAR ENVIRONMENT. ALTHOUGH THE WIND FIELD IS CURRENTLY ELONGATED EAST-WEST...STEADY INTENSIFICATION SEEMS REASONABLE AT THIS TIME...ESPECIALLY AS AN UPPER-LEVEL LOW JUST SOUTHWEST OF THE SYSTEM MOVES AWAY TO THE WEST. KATRINA IS EXPECTED TO BECOME A HURRICANE PRIOR TO LANDFALL...WHICH IS SIMILAR TO THE SHIPS AND GFDL MODELS. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 24/1500Z 24.7N 76.7W 35 KT 12HR VT 25/0000Z 25.4N 77.4W 40 KT 24HR VT 25/1200Z 25.9N 78.4W 45 KT 36HR VT 26/0000Z 26.0N 79.2W 55 KT 48HR VT 26/1200Z 26.1N 80.1W 65 KT 72HR VT 27/1200Z 26.3N 82.5W 40 KT 96HR VT 28/1200Z 27.0N 84.5W 55 KT 120HR VT 29/1200Z 29.0N 86.0W 65 KT |