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| #199968 (Received by flhurricane at: 4:40 PM 08.Jul.2008) TCDAT2 HURRICANE BERTHA DISCUSSION NUMBER 23 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 500 PM EDT TUE JUL 08 2008 BERTHA'S SATELLITE PRESENTATION CONTINUES TO DEGRADE THIS AFTERNOON AND DVORAK DATA T-NUMBERS HAVE FALLEN DURING THE LAST 6 HOURS. THE INITIAL INTENSITY IS LOWERED TO 75 KT BASED ON AN AVERAGE OF THE VARIOUS INTENSITY ESTIMATES. INDEED...BERTHA'S RAPID INTENSIFICATION YESTERDAY HAS BEEN EQUALED BY ITS RAPID WEAKENING TODAY. SUCH INTENSITY FLUCTUATIONS REMAIN A FORECASTING CHALLENGE AND SERVE AS AN IMPORTANT REMINDER FOR THE UNCERTAINTIES ASSOCIATED WITH INTENSITY FORECASTS. GIVEN THE CURRENT TREND IN SATELLITE IMAGERY...CONTINUED WEAKENING IS POSSIBLE IN THE SHORT-TERM. MOST OF THE INTENSITY MODELS SUGGEST THAT BERTHA MIGHT EVEN REGAIN SOME STRENGTH LATER IN THE FORECAST AS THE SHEAR RELAXES AND THE SSTS INCREASE. DUE TO THE UNCERTAINTY...THE OFFICIAL FORECAST SHOWS SLIGHT WEAKENING IN THE SHORT-TERM WITH LITTLE CHANGE THEREAFTER. BERTHA CONTINUES MOVING NORTHWESTWARD WITH AN INITIAL MOTION ESTIMATE OF 310/10. BERTHA SHOULD CONTINUE TO GRADUALLY TURN NORTHWARD OVER THE NEXT COUPLE OF DAYS AS A MID-LEVEL RIDGE OVER THE WESTERN ATLANTIC WEAKENS AND IS REPLACED BY A WEAK TROUGH. THIS EVOLUTION OF THE LARGE-SCALE PATTERN COULD RESULT IN THE STEERING CURRENTS BECOMING RATHER WEAK BEYOND 72 HOURS...AND BERTHA COULD MOVE SLOWLY AND ERRATICALLY TOWARDS THE END OF THE FORECAST. IT IS FOR THIS REASON THAT INTERESTS IN BERMUDA SHOULD CONTINUE TO MONITOR THE PROGRESS OF THIS SYSTEM. TRACK MODELS HAVE NOT CHANGED SIGNIFICANTLY SINCE THE LAST ADVISORY AND NEITHER HAS THE OFFICIAL FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 08/2100Z 22.7N 54.8W 75 KT 12HR VT 09/0600Z 23.6N 56.0W 70 KT 24HR VT 09/1800Z 24.8N 57.4W 65 KT 36HR VT 10/0600Z 26.0N 58.5W 65 KT 48HR VT 10/1800Z 27.0N 59.2W 65 KT 72HR VT 11/1800Z 29.0N 60.0W 60 KT 96HR VT 12/1800Z 31.0N 59.5W 60 KT 120HR VT 13/1800Z 33.0N 58.5W 60 KT $$ FORECASTER RHOME |
