Show Selection: |
#294914 (Received by flhurricane at: 4:43 PM 11.Sep.2009) TCDAT2 TROPICAL STORM FRED DISCUSSION NUMBER 17 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072009 500 PM AST FRI SEP 11 2009 THE CLOUD PATTERN HAS BEEN SIGNIFICANTLY DISRUPTED BY SHEAR AND CONSISTS OF A SHAPELESS AREA OF CONVECTION. THE CENTER IS STILL NEAR A CONCENTRATED AREA OF THUNDERSTORMS BUT MICROWAVE IMAGES... ALTHOUGH SPARSE...CLEARLY SHOW THAT THE LOW-LEVEL CENTER IS BECOMING INCREASINGLY DETACHED FROM THE CONVECTION. GIVEN THE SATELLITE PRESENTATION...AND THE LATEST DVORAK T-NUMBERS...THE INITIAL INTENSITY HAS BEEN LOWERED TO 60 KNOTS. SINCE THE SHEAR OVER FRED IS NOT GOING TO RELAX...WEAKENING IS FORECAST AND FRED WILL GRADUALLY FADE. FRED IS EMBEDDED WITHIN VERY LIGHT STEERING CURRENTS...AND HAS BEEN DRIFTING NORTHEASTWARD. BRAVO TO MOST OF THE TRACK MODELS...WHICH REALLY ANTICIPATED THIS RARE MOTION FOR SUCH A LOW LATITUDE CYCLONE LOCATED IN THE CLIMATOLOGICAL TRADE WIND BELT. LITTLE MOTION IS ANTICIPATED FOR THE NEXT TWO DAYS WHILE THE STEERING CURRENTS ARE LIGHT. THEREAFTER...THE GLOBAL MODELS DEVELOP A SUBTROPICAL RIDGE TO THE NORTH...A PATTERN MORE COMMON FOR SEPTEMBER...PROVIDING A WEST-NORTHWESTWARD STEERING TO WHATEVER IS LEFT OF FRED. THE WESTWARD BEND AFTER THREE DAYS IS THE SOLUTION OF MOST OF THE RELIABLE GUIDANCE AND IS REFLECTED IN THE OFFICIAL FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 11/2100Z 18.1N 34.6W 60 KT 12HR VT 12/0600Z 18.2N 34.4W 55 KT 24HR VT 12/1800Z 18.4N 34.4W 45 KT 36HR VT 13/0600Z 18.8N 34.9W 35 KT 48HR VT 13/1800Z 19.5N 36.0W 30 KT 72HR VT 14/1800Z 21.0N 40.0W 25 KT...REMNANT LOW 96HR VT 15/1800Z 22.5N 45.0W 20 KT...REMNANT LOW 120HR VT 16/1800Z 24.0N 50.5W 20 KT...REMNANT LOW $$ FORECASTER AVILA |