ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM TROPICAL STORM GREG DISCUSSION NUMBER 10 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 8 AM PDT SAT AUG 13 2005 INFRARED AND SHORTWAVE IR IMAGERY OF GREG SHOW AN INTERMITTENTLY EXPOSED CENTER AND FLARE UPS OF CONVECTION IN THE SOUTHERN QUADRANT. NORTHERLY SHEAR IS STILL IMPINGING ON THE SYSTEM AND GREG CONTINUES TO STRUGGLE IN ITS CURRENT ENVIRONMENT. DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB ARE 2.5 RESPECTIVELY GIVING AN INTENSITY ESTIMATE OF 35 KT... WHILE AFWA ESTIMATES ARE SLIGHTLY LOWER. THE INTENSITY FOR GREG REMAINS AT 35 KT. THE INTENSITY FORECAST DOES DEVIATE SLIGHTLY FROM THE PREVIOUS. THE SHORT TERM TREND HOLDS GREG AT 35 KT AND SLOWLY WORKS THE INTENSITY UP TO 60 KT BY 72 HOURS WHICH IS SIMILAR TO SHIPS. HOWEVER... BEYOND 72 HOURS SHIPS KEEPS GREG AT TROPICAL STORM STRENGTH WHILE THE GFDL INCREASES GREG TO A HURRICANE AT 48 HOURS. THE OFFICIAL INTENSITY FORECAST TAKES A CONSERVATIVE APPROACH BY KEEPING GREG AS A TROPICAL STORM IN THE MIDDLE OF THE FORECAST PERIOD AND NUDGING IT TO HURRICANE STATUS IN THE EXTENDED PERIODS. THIS FORECAST MOSTLY FOLLOWS SHIPS... HOWEVER IT DOES TAKE INTO ACCOUNT THE GFDL SOLUTION LATER ON IN THE PERIOD. THE INITIAL MOTION ESTIMATE IS 315/3. GIVEN THAT THE CENTER IS PARTIALLY EXPOSED...THE SHORT TERM MOTION WILL CONTINUE A SLOW MOVEMENT IN THE NORTHWESTWARD DIRECTION... AND IS CONSISTENT WITH THE SHALLOW BETA ADVECTION MODEL. THE DYNAMICAL MODEL SUITE QUICKLY MOVES GREG TO THE SOUTHWEST IN THE SHORT TERM WHICH GIVEN ITS PRESENT MOTION MAY BE UNLIKELY. CONSEQUENTLY... THE OFFICIAL TRACK LEANS MORE TOWARD THE BAMS AND SLOWLY TRENDS BACK TOWARD THE MODEL CONSENSUS LATER ON IN THE FORECAST. FORECASTER SISKO/AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 13/1500Z 15.4N 114.3W 35 KT 12HR VT 14/0000Z 15.6N 114.8W 35 KT 24HR VT 14/1200Z 15.4N 115.7W 40 KT 36HR VT 15/0000Z 15.0N 116.5W 45 KT 48HR VT 15/1200Z 15.0N 118.0W 50 KT 72HR VT 16/1200Z 15.0N 120.5W 60 KT 96HR VT 17/1200Z 15.0N 123.5W 65 KT 120HR VT 18/1200Z 15.5N 126.0W 65 KT $$ NNNN
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Page last modified: Saturday, 13-Aug-2005 15:10:10 UTC