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| #38802 (Received by flhurricane at: 10:34 PM 10.Aug.2005) TCDAT4 TROPICAL STORM IRENE DISCUSSION NUMBER 26 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT WED AUG 10 2005 IRENE'S CLOUD PATTERN HAS BECOME SLIGHTLY BETTER ORGANIZED THIS EVENING. A CONVECTIVE BAND OVER THE EASTERN PORTION OF THE SYSTEM WRAPS NEARLY HALFWAY AROUND THE CIRCULATION. DVORAK INTENSITY ESTIMATES ARE A CONSENSUS 35 KT FROM TAFB...SAB...AND AFWA. THIS SUPPORTS RE-UPGRADING THE CYCLONE TO TROPICAL STORM STATUS. THE UPPER-TROPOSPHERIC OUTFLOW IS BECOMING BETTER DEFINED EXCEPT TO THE SOUTH WHERE IT IS BEING IMPEDED BY AN UPPER-LEVEL CYCLONE TO THE SOUTHWEST OF THE STORM. WATER VAPOR IMAGERY AND ANALYSES FROM THE UNIVERSITY OF WISCONSIN CIMSS SHOW THAT THE NORTHERLY MID- TO UPPER-LEVEL FLOW THAT HAD BEEN DISRUPTING THE TROPICAL CYCLONE IS ABATING AND THAT IRENE IS MOVING INTO AN AREA OF DECREASING VERTICAL SHEAR. STRENGTHENING IS FORECAST...AS IN THE PREVIOUS ADVISORY. AS USUAL...THE FORECAST WIND SPEEDS IN THE 3 TO 5 DAY TIME FRAME HAVE CONSIDERABLE UNCERTAINTY OWING TO A LACK OF SKILL IN LONGER-RANGE TROPICAL CYCLONE INTENSITY PREDICTION. RECENT CENTER FIXES FROM BOTH GEOSTATIONARY AND MICROWAVE IMAGERY ARE SOMEWHAT TO THE NORTH OF THE PREVIOUS TRACK. HOWEVER...FOR CONTINUITY'S SAKE...I HAVE ADJUSTED THE CURRENT MOTION ONLY SLIGHTLY TO THE RIGHT...290/11. THE MAIN STEERING FEATURE THAT CONCERNS US IS A MID-TROPOSPHERIC RIDGE THAT THE GLOBAL MODELS ARE FORECASTING TO BUILD NEAR AND JUST EAST OF THE U.S. MID-ATLANTIC STATES IN 3 TO 5 DAYS. IT IS TOO EARLY TO DETERMINE WHETHER THIS RIDGE WILL DRIVE IRENE TO THE SOUTHEAST U.S. COAST. IT IS STILL POSSIBLE THAT THE TROPICAL CYCLONE WILL BE ABLE TO MOVE MORE NORTHWARD INTO A WEAKNESS IN THE RIDGE...AS SUGGESTED BY SOME OF THE TRACK GUIDANCE SUCH AS THE U.K. MET. OFFICE GLOBAL MODEL AND THE LATEST GFDL RUN...OR MOVE MORE WESTWARD AND REACH THE COAST AS SHOWN BY THE ECMWF AND GFDN. THE OFFICIAL FORECAST TRACK HAS BEEN SHIFTED A LITTLE TO THE RIGHT OF THE PREVIOUS ONE...BUT IS STILL WELL TO THE LEFT OF THE DYNAMICAL MODEL CONSENSUS. THE NHC FORECAST TRACK IS ALSO VERY SIMILAR TO THE LATEST FSU SUPERENSEMBLE TRACK. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 11/0300Z 23.5N 59.8W 35 KT 12HR VT 11/1200Z 24.2N 61.5W 40 KT 24HR VT 12/0000Z 25.4N 63.8W 45 KT 36HR VT 12/1200Z 26.3N 65.7W 50 KT 48HR VT 13/0000Z 27.2N 67.5W 55 KT 72HR VT 14/0000Z 28.5N 70.0W 60 KT 96HR VT 15/0000Z 30.5N 72.5W 65 KT 120HR VT 16/0000Z 32.5N 75.0W 70 KT |
