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| #201660 (Received by flhurricane at: 4:40 PM 18.Jul.2008) TCDAT2 HURRICANE BERTHA DISCUSSION NUMBER 63 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 500 PM EDT FRI JUL 18 2008 SATELLITE IMAGES INDICATE THAT BERTHA IS NOW A HURRICANE AGAIN. THE EYE HAS BECOME BETTER-DEFINED WITH DEEP CONVECTION INCREASING AROUND A CONSOLIDATING EYEWALL. THE INITIAL INTENSITY IS RAISED TO 65 KT IN AGREEMENT WITH THE SATELLITE CLASSIFICATION FROM SAB. BERTHA SHOULDN'T BE A HURRICANE FOR TOO LONG AS IT IS FORECAST TO BE OVER WATERS LESS THAN 70F BY THIS TIME TOMORROW. A SLOW WEAKENING IS INDICATED...WHICH IS IN GOOD AGREEMENT WITH MOST GUIDANCE. PHASE DIAGRAMS FROM FLORIDA STATE INDICATE THAT THE HURRICANE SHOULD BEGIN ITS EXTRATROPICAL TRANSITION IN A DAY OR SO...WITH THE PROCESS COMPLETE IN ABOUT 48 HR. BERTHA CONTINUES MOVING TO THE NORTHEAST...NOW AT ABOUT 19 KT. THERE IS NO CHANGE TO THE SYNOPTIC REASONING. THE HURRICANE SHOULD ACCELERATE OUT TO SEA IN A WELL-DEFINED STEERING CURRENT BETWEEN A HIGH TO THE SOUTHEAST AND THE MIDDLE-LATITUDE WESTERLIES. MODEL GUIDANCE IS GENERALLY SHOWING GREATER INTERACTION THAN EARLIER WITH BERTHA AND AN APPROACHING TROUGH FROM NORTH AMERICA... RESULTING IN A SLIGHTLY MORE POLEWARD TRACK OF THE CYCLONE. THE OFFICIAL FORECAST IS SHIFTED WESTWARD TO ACCOUNT FOR THIS TREND AND LIES ON THE EASTERN SIDE OF THE GUIDANCE ENVELOPE. FORECAST POSITIONS AND MAX WINDS INITIAL 18/2100Z 37.6N 50.6W 65 KT 12HR VT 19/0600Z 39.8N 48.2W 65 KT 24HR VT 19/1800Z 42.9N 44.8W 60 KT 36HR VT 20/0600Z 46.7N 40.6W 55 KT...BECOMING EXTRATROPICAL 48HR VT 20/1800Z 51.5N 36.0W 50 KT...EXTRATROPICAL 72HR VT 21/1800Z 61.0N 23.0W 50 KT...EXTRATROPICAL 96HR VT 22/1800Z...ABSORBED $$ FORECASTER BLAKE |
