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| #200423 (Received by flhurricane at: 10:58 AM 11.Jul.2008) TCDAT2 HURRICANE BERTHA DISCUSSION NUMBER 34 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 1100 AM EDT FRI JUL 11 2008 MICROWAVE DATA CONTINUES TO SHOW A SMALL FRAGMENT OF THE INNER EYEWALL WITHIN A BETTER DEFINED AND LARGER RING OF CONVECTION ASSOCIATED WITH THE OUTER EYEWALL. CONVENTIONAL VIS/IR IMAGES SHOW THAT BERTHA'S CLOUD PATTERN HAS CHANGED LITTLE WITH GOOD OUTFLOW IN ALL QUADRANTS. DVORAK T-NUMBERS STILL SUGGEST AN INITIAL INTENSITY OF 75 KNOTS. THE FIRST RECONNAISSANCE MISSION INTO BERTHA WILL BE LATER TODAY...SO I WILL BE MORE CONFIDENT WITH THE INITIAL INTENSITY WHEN THE PLANE GETS THERE. THE CURRENT CLOUD PATTERN CONFIGURATION...ANNULAR TYPE...AND LOW SHEAR SUGGEST THAT THE INTENSITY WILL NOT CHANGE IN THE NEXT DAY OR SO. THEREFORE...BERTHA IS KEPT AT 75 KNOTS UNTIL SHEAR INCREASES AND MOVES OVER A COOLER OCEAN. THEN...A GRADUAL WEAKENING IS INDICATED. ALTHOUGH IT APPEARS THAT THE OUTER EYEWALL COULD SHRINK RESULTING IN INTENSIFICATION... I AM NOT CONSIDERING IT IN THIS FORECAST BECAUSE I HAVE NO IDEA WHEN OR IF THIS CYCLE WILL OCCUR. BERTHA IS MOVING VERY SLOWLY...AS ANTICIPATED...TOWARD THE NORTHWEST OR 320 DEGREES AT 5 KNOTS IN BETWEEN A SMALL SUBTROPICAL RIDGE AND AN APPROACHING SHORTWAVE TROUGH. THIS PATTERN SHOULD KEEP BERTHA WITHIN VERY WEAK STEERING CURRENTS FOR THE NEXT 2 OR 3 DAYS. BERTHA IS EXPECTED TO TURN MORE TO THE NORTH AND EVENTUALLY MORE TO THE NORTH-NORTHEAST. THIS WILL BE VERY SLOW AND BERTHA IS NOT EXPECTED TO MOVE MORE THAN 300 N MI IN THREE DAYS. THIS IS CONSISTENT WITH LATEST GUIDANCE WHICH SHOWS THE CORE OF BERTHA MOVING WELL EAST OF BERMUDA BUT TROPICAL STORM FORCE WINDS EXTEND FARTHER OUT AND COULD REACH THE ISLAND AND ADJACENT WATERS. THEREFORE...GIVEN UNCERTAINTIES IN THE FORECASTS OF BERTHA'S...TRACK... INTENSITY...AND SIZE...THE WEATHER SERVICE OF BERMUDA HAS ISSUED A TROPICAL STORM WATCH FOR BERMUDA. FORECAST POSITIONS AND MAX WINDS INITIAL 11/1500Z 28.5N 62.0W 75 KT 12HR VT 12/0000Z 29.2N 62.5W 75 KT 24HR VT 12/1200Z 30.2N 62.6W 75 KT 36HR VT 13/0000Z 30.8N 62.2W 75 KT 48HR VT 13/1200Z 31.5N 61.5W 70 KT 72HR VT 14/1200Z 32.5N 60.5W 65 KT 96HR VT 15/1200Z 34.5N 59.5W 60 KT 120HR VT 16/1200Z 37.0N 58.5W 55 KT $$ FORECASTER AVILA |
