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| #42020 (Received by flhurricane at: 5:08 AM 26.Aug.2005) TCDAT2 HURRICANE KATRINA DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT FRI AUG 26 2005 DUE TO THE SOUTHWESTWARD PATH TAKEN BY KATRINA OVER EXTREME SOUTHERN FLORIDA...ITS CENTER SPENT ONLY ABOUT SEVEN HOURS OVER LAND...AND MUCH OF THAT TIME OVER THE RELATIVELY MOIST EVERGLADES. AS A RESULT OF THIS AND THE FAVORABLE ATMOSPHERIC ENVIRONMENT... KATRINA DID NOT WEAKEN ALL THAT MUCH OVERNIGHT. THE CENTER CROSSED THE COAST OF SOUTHWESTERN FLORIDA AT ABOUT 0530Z... EMERGING OVER THE WARM WATERS OF THE GULF OF MEXICO. WSR-88D RADAR IMAGERY FROM MIAMI AND KEY WEST STILL DEPICT AN IMPRESSIVE CYCLONE... WITH STRONG CONVECTION CONTINUING JUST SOUTHEAST OF THE CENTER... WHICH STILL QUALIFIES AS SOMEWHAT OF AN EYEWALL. A SECONDARY BUT STRONG CURVED BAND ALSO EXTENDS FROM JUST EAST OF THE CENTER SOUTHWESTWARD ALONG THE ENTIRE CHAIN OF THE FLORIDA KEYS... AND A LARGER OUTER BAND EXTENDS ALL THE WAY AROUND THE SOUTHERN PORTIONS OF THE CIRCULATION BETWEEN THE KEYS AND CUBA TO WEST OF DRY TORTUGAS. WHILE THE LATEST DOPPLER RADAR VELOCITIES ONLY SUPPORT 60 KT AT THE SURFACE... THESE VALUES ARE STEADILY CLIMBING... AND THE FIRST DVORAK ESTIMATES OVER THE GULF ARE A UNANIMOUS T4.0/65 KT. THEREFORE... KATRINA IS REASSIGNED HURRICANE STATUS WITH INTENSITY OF 65 KT. RADAR IMAGERY INDICATES THAT KATRINA HAS STARTED TO MOVE NEARLY DUE WESTWARD... AND THE INITIAL MOTION ESTIMATE IS 260/4. THIS MOTION IS EXPECTED TO CONTINUE FOR THE NEXT SEVERAL HOURS TO THE SOUTH OF AN EASTWARD EXTENSION OF THE MID-LEVEL RIDGE CENTERED OVER TEXAS. THE DYNAMICAL MODELS GENERALLY AGREE THAT THIS RIDGE WILL WEAKEN AND MIGRATE WESTWARD... ALLOWING KATRINA TO GRADUALLY TURN NORTHWARD INTO A WEAKNESS IN THE RIDGING. THE NEW SUITE OF GUIDANCE HAS SHIFTED A LITTLE TO THE WEST... AS HAS THE OFFICIAL FORECAST... WHICH IS A BLEND OF THE PREVIOUS ADVISORY AND THE LATEST MODEL CONSENSUS. ALL INDICATIONS ARE THAT KATRINA WILL BE A DANGEROUS HURRICANE IN THE NORTHEASTERN GULF OF MEXICO WITHIN THE NEXT COUPLE OF DAYS. THIS SEEMS EVEN MORE LIKELY NOW GIVEN ITS CURRENT STRENGTH EMERGING AGAIN OVER WATER. AS KATRINA MOVES FARTHER NORTH IN THE EASTERN GULF OF MEXICO... ATMOSPHERIC CONDITIONS SHOULD ONLY BECOME MORE CONDUCIVE FOR STRENGTHENING AS A LARGE UPPER LEVEL ANTICYCLONE DOMINATES OVER THE GULF OF MEXICO. THE OFFICIAL FORECAST IS CLOSE TO THE SHIPS GUIDANCE IN BRINGING KATRINA TO 90 KT BY 72 HOURS.... BUT THIS COULD BE CONSERVATIVE SINCE THE GFDL AND GFDN FORECAST A MAJOR HURRICANE. IT IS CERTAINLY POSSIBLE THAT KATRINA COULD ATTAIN MAJOR HURRICANE STATUS BEFORE MAKING LANDFALL SOMEWHERE ON THE NORTHERN GULF COAST. FORECASTER KNABB FORECAST POSITIONS AND MAX WINDS INITIAL 26/0900Z 25.3N 81.5W 65 KT 12HR VT 26/1800Z 25.2N 82.6W 70 KT 24HR VT 27/0600Z 25.4N 83.8W 75 KT 36HR VT 27/1800Z 25.9N 84.6W 80 KT 48HR VT 28/0600Z 26.6N 85.4W 85 KT 72HR VT 29/0600Z 28.5N 86.5W 90 KT 96HR VT 30/0600Z 33.0N 84.5W 40 KT...INLAND 120HR VT 31/0600Z 39.0N 79.0W 25 KT...INLAND |
