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| #374089 (Received by flhurricane at: 4:59 AM 06.Sep.2010) TCDAT5 TROPICAL STORM HERMINE DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL102010 400 AM CDT MON SEP 06 2010 A SERIES OF MICROWAVE OVERPASSES AND ASCAT DATA SHOW THAT THE CENTER OF THE TROPICAL CYCLONE IS A LITTLE NORTHEAST OF EARLIER ESTIMATES. ASCAT...WHICH HAS A WELL DOCUMENTED LOW BIAS...REVEALED SEVERAL 30-KT WIND VECTORS TO THE EAST AND SOUTHEAST OF THE CENTER...AND NOAA BUOY 42055 HAS REPORTED PEAK 1-MINUTE SUSTAINED WINDS BETWEEN 30 AND 35 KT DURING THE PAST FEW HOURS. BASED ON THESE DATA THE SYSTEM IS UPGRADED TO A 35-KT TROPICAL STORM....THE EIGHTH OF THE 2010 ATLANTIC HURRICANE SEASON. HERMINE IS FORECAST TO TRAVERSE WARM WATER AND REMAIN IN A LOW SHEAR ENVIRONMENT UNTIL LANDFALL. AS A RESULT...STEADY STRENGTHENING IS PREDICTED AND THE OFFICIAL INTENSITY FORECAST IS NEAR THE CONSENSUS OF THE GUIDANCE. THE SOMEWHAT UNCERTAIN INITIAL MOTION ESTIMATE IS 360/7. HERMINE IS FORECAST TO TURN NORTH-NORTHWESTWARD TODAY AS A MID-LEVEL RIDGE BUILDS ACROSS THE NORTHERN GULF OF MEXICO. WHILE THE TRACK MODELS ARE IN GOOD AGREEMENT ON THIS SCENARIO...THE GUIDANCE HAS SHIFTED NORTHWARD WHICH HAS REQUIRED A NORTHWARD ADJUSTMENT OF THE TRACK FORECAST. THERE ARE ALSO NOTICEABLE DIFFERENCES IN THE PREDICTED FORWARD SPEED OF HERMINE...WITH THE GLOBAL MODELS SHOWING A FASTER MOTION THAN THE GFDL/HWRF. FOR NOW...THE FORECAST FORWARD MOTION OF THE CYCLONE IS CLOSE TO THE CONSENSUS. THE NORTHWARD SHIFT IN THE TRACK FORECAST REQUIRED THE ISSUANCE OF A TROPICAL STORM WARNING FOR A PORTION OF THE SOUTH TEXAS COAST. FORECAST POSITIONS AND MAX WINDS INITIAL 06/0900Z 21.6N 95.0W 35 KT 12HR VT 06/1800Z 22.9N 95.8W 45 KT 24HR VT 07/0600Z 24.9N 97.2W 50 KT 36HR VT 07/1800Z 26.8N 98.4W 35 KT...INLAND 48HR VT 08/0600Z 28.8N 99.7W 25 KT...INLAND 72HR VT 09/0600Z 33.2N 99.6W 20 KT...POST-TROP/REMNT LOW 96HR VT 10/0600Z...DISSIPATED $$ FORECASTER BROWN |
