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| #46866 (Received by flhurricane at: 4:40 AM 19.Sep.2005) TCDAT3 TROPICAL STORM RITA DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT MON SEP 19 2005 THE NEW RECONAISSANCE AIRCRAFT IN THE SYSTEM AT 07Z FOUND THAT THE PRESSURE HAD FALLEN TO 999 MB...AND FIRST SATELLITE IMAGES AFTER THE ECLIPSE SHOW THAT CONVECTION IS NOW WRAPPING AROUND TO THE NORTHWEST OF THE CENTER AND HAS TAKEN A MORE BANDED APPEARANCE. A DROPSONDE IN THE NORTHWEST QUADRANT HAD 44 KT AT THE SURFACE...WITH FLIGHT LEVEL WINDS IN THIS QUADRANT OF 57 KT. THE NORTHEAST QUADRANT HAS NOT YET BEEN SAMPLED...AND I PRESUME THAT HIGHER WINDS WILL BE FOUND THERE DURING THE NEXT HOUR OR SO. THE INITIAL INTENSITY IS INCREASED TO 50 KT. THE LAST TWO AIRCRAFT FIXES INDICATE AN ALMOST DUE WEST MOTION...BUT WITH ALL THE CENTER REFORMATIONS THAT HAVE OCCURRED IT IS DIFFICULT TO ASCERTAIN A REPRESENTATIVE MOTION. MY BEST JUDGEMENT IS 280/8. RITA HAS ALREADY PASSED THE LONGITUDE OF THE BREAK IN THE SUBTROPICAL RIDGE...AND WILL COME UNDER INCREASING PRESSURE TO HAVE THE TRACK NUDGE TO THE LEFT. FURTHERMORE...NOW THAT THE CONVECTION IS BECOMING A LITTLE MORE SYMMETRIC...THERE SHOULD BE LESS LIKELIHOOD OF ADDITIONAL NORTHWARD REFORMATIONS OF THE CENTER. MODEL GUIDANCE ADJUSTED TO THE CURRENT LOCATION IS VERY TIGHTLY CLUSTERED ON A PATH THROUGH THE FLORIDA STRAITS SOUTH OF KEY WEST...AND I HAVE ADJUSTED THE OFFICIAL FORECAST SLIGHTLY SOUTH OF THE PREVIOUS ADVISORY. THERE HAS BEEN A FAIRLY SIGNIFICANT SHIFT IN THE GUIDANCE LATE IN THE FORECAST PERIOD...WITH THE GLOBAL MODELS ABRUPTLY WEAKENING THE MID-LEVEL HIGH OVER THE WESTERN GULF AND ALLOWING RITA TO BEGIN A SHARPER RECURVATURE TRACK. WHILE I HAVE ADJUSTED THE 120-HR POINT ABOUT 120 NM NORTH OF THE PREVIOUS ADVISORY...I AM STILL WELL TO THE LEFT OF MOST OF THE 120-HR GUIDANCE. WATER VAPOR IMAGERY SHOWS THAT THE UPPER-LEVEL LOW IN THE NORTHWEST CARIBBEAN IS SHIFTING EASTWARD...AND AS IT DOES SO THE SOUTHERLY SHEAR OVER RITA WILL CONTINUE TO DECREASE. THIS SHOULD ALLOW FOR A FASTER DEVELOPMENT RATE. THE OFFICIAL FORECAST IS VERY CLOSE TO THE SHIPS GUIDANCE. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 19/0900Z 22.7N 74.3W 50 KT 12HR VT 19/1800Z 23.1N 76.0W 60 KT 24HR VT 20/0600Z 23.6N 78.5W 70 KT 36HR VT 20/1800Z 24.0N 81.2W 80 KT 48HR VT 21/0600Z 24.2N 84.0W 90 KT 72HR VT 22/0600Z 24.5N 88.5W 100 KT 96HR VT 23/0600Z 25.5N 92.5W 100 KT 120HR VT 24/0600Z 27.5N 96.0W 95 KT |
