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| #199289 (Received by flhurricane at: 4:55 PM 05.Jul.2008) TCDAT2 TROPICAL STORM BERTHA DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 500 PM EDT SAT JUL 05 2008 BERTHA HAS CHANGED LITTLE IN ORGANIZATION SINCE THIS MORNING. THE CYCLONE CONTINUES TO MAINTAIN AN AREA OF CONVECTION NEAR AND TO THE NORTH OF THE CENTER. DVORAK INTENSITY ESTIMATES ARE A UNANIMOUS 45 KT...WHICH REMAINS THE INITIAL INTENSITY. ENVIRONMENTAL CONDITIONS ARE FORECAST TO BECOME MORE CONDUCIVE FOR STRENGTHENING ALONG THE PROJECTED PATH. BERTHA IS CURRENTLY OVER SSTS OF ABOUT 25 DEGREES CELSIUS...BUT THE SSTS WILL BE INCREASING BY ABOUT ONE DEGREE PER DAY DURING THE NEXT 3 DAYS. SHEAR IS EXPECTED TO REMAIN LOW AT LEAST DURING THE NEXT 72 HOURS...BUT PROJECTED TO INCREASE A LITTLE THEREAFTER. THE NEW INTENSITY FORECAST IS UNCHANGED FROM THE PREVIOUS ADVISORY WHICH SHOWED BERTHA BECOMING A HURRICANE IN ABOUT 3 DAYS...FOLLOWED BY LITTLE CHANGE IN STRENGTH AT DAYS 4 AND 5. THE INTENSITY FORECAST IS SIMILAR TO THE CONSENSUS OF THE HWRF... GFDL...LGEM AND SHIPS MODELS. BERTHA CONTINUES RACING WESTWARD WITH AN INITIAL MOTION OF 275/18. A GENERAL WEST TO WEST-NORTHWESTWARD MOTION SHOULD CONTINUE FOR THE NEXT COUPLE OF DAYS. THEREAFTER...THERE IS A VERY LARGE SPREAD IN THE MODEL GUIDANCE. THE MODELS WHICH MAINTAIN A DEEPER AND STRONGER BERTHA TURN THE CYCLONE MORE NORTHWESTWARD IN RESPONSE TO A WEAKNESS IN THE RIDGE CURRENTLY OVER THE CENTRAL ATLANTIC. MEANWHILE...THE MODELS THAT DEPICT A WEAKER AND SHALLOWER CYCLONE CONTINUE TO TRACK IT WESTWARD SOUTH OF THE LOW-LEVEL RIDGE OVER THE ATLANTIC. THE NHC FORECAST TRACK ASSUMES THAT BERTHA WILL REMAIN DEEP ENOUGH TO DECELERATE DUE TO THE WEAKER RIDGE. THE NEW FORECAST TRACK IS JUST A LITTLE SOUTH OF THE PREVIOUS ADVISORY THROUGH 72 HOURS...BUT SIMILAR THEREAFTER...AND IN BEST AGREEMENT WITH THE ECMWF...NOGAPS...AND THE GUNA MODEL CONSENSUS. IT IS TOO EARLY TO DETERMINE IF BERTHA WILL EVER POSE A THREAT TO ANY LAND AREAS. FORECAST POSITIONS AND MAX WINDS INITIAL 05/2100Z 16.7N 39.3W 45 KT 12HR VT 06/0600Z 17.1N 42.1W 45 KT 24HR VT 06/1800Z 17.8N 45.9W 50 KT 36HR VT 07/0600Z 18.5N 49.5W 55 KT 48HR VT 07/1800Z 19.3N 52.8W 60 KT 72HR VT 08/1800Z 20.8N 58.1W 65 KT 96HR VT 09/1800Z 22.5N 63.0W 65 KT 120HR VT 10/1800Z 25.0N 67.0W 65 KT $$ FORECASTER BROWN |
