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| #356228 (Received by flhurricane at: 10:37 PM 29.Jun.2010) TCDAT1 HURRICANE ALEX DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012010 1000 PM CDT TUE JUN 29 2010 ALEX HAS GRADUALLY BECOME BETTER ORGANIZED ON SATELLITE IMAGES AND DVORAK CLASSIFICATIONS FROM BOTH TAFB AND SAB CONTINUE TO SUPPORT A CURRENT INTENSITY OF 65 KT. AN AIR FORCE RESERVE UNIT HURRICANE HUNTER AIRCRAFT PASSED THROUGH THE CENTER ON A NORTHWEST TO SOUTHEAST LEG AND MEASURED A CENTRAL PRESSURE OF 973 MB BY DROPSONDE. THE SFMR ABOARD THE PLANE MEASURED A SURFACE WIND OF 62 KT JUST TO THE SOUTHEAST OF THE CENTER. SOON THEREAFTER...THE AIRCRAFT HAD TO DEPART THE AREA DUE TO RADAR FAILURE. BASED ON THE SUBSTANTIAL DROP IN CENTRAL PRESSURE SINCE EARLIER TODAY AND THE FACT THAT HIGHER SURFACE WINDS ARE LIKELY OCCURRING IN THE NORTHEAST QUADRANT...ALEX IS BEING UPGRADED TO A 65-KT HURRICANE FOR THIS ADVISORY. VERTICAL SHEAR IS FORECAST TO REMAIN BELOW 10 KT FOR THE NEXT 24-48 HOURS SO THE HURRICANE SHOULD REMAIN IN AN ENVIRONMENT CONDUCIVE FOR INTENSIFICATION UP TO LANDFALL. THE SHIPS RAPID INTENSIFICATION INDEX SHOWS A 33 PERCENT PROBABILITY OF RAPID INTENSIFICATION...I.E. A 30-KT INCREASE OVER 24 HOURS. HOWEVER...NONE OF THE OTHER NUMERICAL INTENSITY GUIDANCE SHOWS ALEX STRENGTHENING BEYOND CATEGORY ONE STATUS PRIOR TO LANDFALL. THE OFFICIAL INTENSITY IS VERY CLOSE TO THE LGEM GUIDANCE AND ABOUT THE SAME AS THAT FROM THE PREVIOUS PACKAGE. ALEX WOBBLED WESTWARD OVER THE PAST SEVERAL HOURS. AFTER SOME SMOOTHING...THE INITIAL MOTION ESTIMATE IS 280/8. SHORT-TERM FORECASTS FROM DYNAMICAL MODELS SUCH AS THE GFDL AND GFS SUGGEST THAT THE WESTWARD MOTION IS TEMPORARY AND THAT A WEST-NORTHWESTWARD TRACK SHOULD RESUME SOON. THE FLOW TO THE SOUTH OF A MID- TROPOSPHERIC RIDGE SHOULD STEER THE HURRICANE ON A GENERALLY WEST-NORTHWESTWARD COURSE ACROSS THE WESTERN GULF OF MEXICO...WITH ALEX REACHING THE COAST IN ABOUT 24 HOURS. BECAUSE OF THE JOG TO THE LEFT...THE NEW NHC FORECAST TRACK HAS BEEN SHIFTED SLIGHTLY TO THE SOUTH OF THE PREVIOUS ONE. IT SHOULD BE REPEATED THAT ONE SHOULD NOT FOCUS ON THE EXACT PREDICTED LANDFALL POINT BECAUSE OF TRACK FORECAST UNCERTAINTIES...AND ALSO BECAUSE THIS IS A LARGE TROPICAL CYCLONE. FORECAST POSITIONS AND MAX WINDS INITIAL 30/0300Z 23.1N 94.8W 65 KT 12HR VT 30/1200Z 23.7N 96.0W 75 KT 24HR VT 01/0000Z 24.2N 97.6W 80 KT 36HR VT 01/1200Z 24.6N 99.2W 55 KT...INLAND 48HR VT 02/0000Z 24.5N 101.0W 30 KT...INLAND 72HR VT 03/0000Z...DISSIPATED INLAND $$ FORECASTER PASCH |
