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| #5361 (Received by flhurricane at: 9:44 AM 16.Aug.2004) TCDAT5 TROPICAL STORM EARL DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT MON AUG 16 2004 THE INITIAL POSITION IS HIGHLY UNCERTAIN AND IS BASED...TO A LARGE DEGREE...ON EXTRAPOLATION AND ASSUMING THAT THE CENTER IS SOMEWHERE CLOSE TO THE EASTERNMOST BURST OF DEEP CONVECTION. THIS POSITION IS AT LEAST 30 NMI AHEAD OF THE CONVENTIONAL SATELLITE POSITION ESTIMATES. THE DVORAK INTENSITY ESTIMATES HAVE DROPPED TO 30 KT. HOWEVER...GIVEN THE RECENT DEVELOPMENT OF COLD TOPPED CONVECTION NEAR THE ALLEGED CENTER...THE INTENSITY WILL BE HELD AT 40 KT UNTIL RECON GETS OUT THERE LATER THIS MORNING TO INVESTIGATE THE CYCLONE. THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 285/18. SOME EARLIER SSMI AND AMSU DATA SUGGEST THAT EARL HAS SLOWED SOME...BUT I AM RELUCTANT TO BRING DOWN THE FORWARD SPEED TOO MUCH AT THIS TIME. THE NHC MODEL GUIDANCE IS MORE TIGHTLY CLUSTERED NOW ON A GENERAL TRACK ACROSS THE YUCATAN PENINSULA IN 84-96 HOURS. HOWEVER...THE GFDL HAS MADE A MAJOR SHIFT TO THE RIGHT ON THIS FORECAST CYCLE. IT IS NOW THE RIGHTMOST OF ALL THE MODEL GUIDANCE...EXCEPT FOR THE GFS 10-MEMBER ENSEMBLE MODEL. THE GFS ENSEMBLE MODEL BRINGS EARL TO NEAR THE YUCATAN CHANNEL IN 120 HOURS. THE SUBTROPICAL RIDGE TO THE NORTH IS EXPECTED TO REMAIN INTACT THROUGH AT LEAST 72 HOURS... AFTER WHICH ALL OF THE MODELS AGREE ON BRINGING A SHORTWAVE INTO THE SOUTHERN PLAINS AND NORTHERN MEXICO...WHICH HELPS TO ERODE THE RIDGE OVER THE WESTERN GULF OF MEXICO. ONLY THE UKMET AND CANADIAN MODELS MAINTAIN A STRONG RIDGE ACROSS THE GULF. THE REST OF THE MODELS HAVE ONLY 5-10 KT OF WIND AT 500 MB IN THE WESTERN GULF IN 4-5 DAYS...WHICH COULD ALLOW FOR EARL TO SLOW AND MOVE MORE POLEWARD. THE OFFICIAL TRACK IS TO THE RIGHT OF THE PREVIOUS TRACK AND IS CLOSE TO THE SPEED OF THE NHC MODEL CONSENSUS. ALL OF THE GLOBAL AND REGIONAL MODELS AGREE ON KEEPING THE UPPER-LEVEL WINDS UNDER 15 KT AND GENERALLY OUT OF THE EAST ACROSS THE ENTIRE CARIBBEAN SEA AHEAD OF EARL. THEREFORE...AT LEAST STEADY INTENSIFICATION IS CALLED FOR. THE INTENSITY FORECAST IS CLOSE TO THE SHIPS MODEL...AND ACCOUNTS FOR LAND INTERACTION WITH THE YUCATAN PENINSULA BY 96 HOURS...BUT IS NOT NEARLY AS STRONG AS THE GFDL MODEL WHICH BRINGS EARL UP TO 91 KT IN ABOUT 72 HOURS. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 16/0900Z 13.2N 67.2W 40 KT 12HR VT 16/1800Z 14.1N 70.4W 45 KT 24HR VT 17/0600Z 15.0N 74.6W 50 KT 36HR VT 17/1800Z 15.7N 78.1W 55 KT 48HR VT 18/0600Z 16.3N 81.2W 65 KT 72HR VT 19/0600Z 18.0N 86.0W 75 KT 96HR VT 20/0600Z 20.5N 90.5W 60 KT...INLAND 120HR VT 21/0600Z 22.5N 94.5W 70 KT...OVER WATER |
