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| #198802 (Received by flhurricane at: 11:08 AM 03.Jul.2008) TCDAT2 TROPICAL STORM BERTHA DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 1100 AM EDT THU JUL 03 2008 THIS MORNINGS VISIBLE SATELLITE IMAGERY SHOW THAT THE CLOUD PATTERN HAS BECOME BETTER ORGANIZED WITH TWO DISTINCT SPIRALING BANDS OF DEEP CONVECTION. DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB ARE 35 KT....THEREFORE THE SYSTEM HAS BEEN UPGRADED TO A TROPICAL STORM...THE SECOND OF THE 2008 ATLANTIC SEASON. RECENT MICROWAVE AND VISIBLE SATELLITE IMAGERY SUGGEST THAT THE CENTER IS A LITTLE FARTHER NORTH AND WEST OF THE PREVIOUS ESTIMATES. BECAUSE OF THE RELOCATION OF THE CENTER...THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 285/12...A LITTLE FASTER THAN BEFORE. BERTHA IS LOCATED TO THE SOUTH OF A MID-LEVEL RIDGE OVER THE EASTERN ATLANTIC AND MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON A CONTINUED WEST-NORTHWESTWARD TRACK DURING THE NEXT 2-3 DAYS. THEREAFTER...THE MODELS SUGGEST THAT BERTHA WILL APPROACH A WEAKNESS IN THE SUBTROPICAL RIDGE OVER THE CENTRAL ATLANTIC. THE GFS...HWRF...AND GFDL MODELS THEREFORE SHOW A NORTHWESTWARD TURN LATE IN THE FORECAST PERIOD. THE NEW OFFICIAL FORECAST IS A LITTLE FASTER AND NORTH OF THE PREVIOUS TRACK AND IS CLOSE TO A CONSENSUS OF THE GFDL...GFS...HWRF...AND ECMWF MODELS. VERTICAL WIND SHEAR IS FORECAST TO REMAIN LIGHT DURING THE NEXT FEW DAYS...HOWEVER...COOLER WATERS ALONG THE FORECAST TRACK SHOULD LIMIT INTENSIFICATION. SSTS ALONG THE TRACK ARE EXPECTED TO INCREASE AFTER 48 HOURS WHICH WOULD FAVOR SOME STRENGTHENING. HOWEVER...LATE IN THE FORECAST PERIOD SOUTHWESTERLY SHEAR IS EXPECTED TO INCREASE WHICH AGAIN SHOULD HALT STRENGTHENING. THE SHIPS AND LGEM MODELS PREDICT BERTHA TO BECOME A HURRICANE IN 72 TO 96 HOURS. HOWEVER...THE NEW INTENSITY FORECAST WILL REMAIN A LITTLE MORE CONSERVATIVE WHICH IS CLOSER TO THE GFDL AND HWRF SOLUTIONS. OUTER RAINBANDS ASSOCIATED WITH BERTHA ARE EXPECTED TO BRING GUSTY WINDS AND LOCALLY HEAVY RAINFALL TO PORTIONS OF THE SOUTHERN CAPE VERDE ISLANDS DURING THE NEXT 24 HOURS. FORECAST POSITIONS AND MAX WINDS INITIAL 03/1500Z 13.3N 24.7W 35 KT 12HR VT 04/0000Z 13.8N 26.7W 40 KT 24HR VT 04/1200Z 14.7N 29.4W 45 KT 36HR VT 05/0000Z 15.6N 32.5W 45 KT 48HR VT 05/1200Z 16.6N 35.8W 50 KT 72HR VT 06/1200Z 18.5N 42.5W 55 KT 96HR VT 07/1200Z 21.5N 48.5W 55 KT 120HR VT 08/1200Z 25.0N 52.0W 55 KT $$ FORECASTER BROWN |
