000 WTNT42 KNHC 150847 TCDAT2 TROPICAL STORM GERT DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072011 500 AM AST MON AUG 15 2011 GERT HAS STRENGTHENED OVERNIGHT. AN 0543 UTC AMSR-E PASS AND DOPPLER RADAR DATA FROM BERMUDA INDICATE THAT GERT HAS A FAIRLY WELL-DEVELOPED INNER CORE AND A SPIRAL BAND THAT WRAPS ABOUT THREE-QUARTERS OF THE WAY AROUND THE CENTER. IN ADDITION... SATELLITE IMAGES INDICATE THAT BANDING FEATURES HAVE BECOME MORE ESTABLISHED DURING THE PAST SEVERAL HOURS. THE INITIAL WIND SPEED IS INCREASED TO 50 KT...WHICH IS SLIGHTLY HIGHER THAN THE DVORAK CLASSIFICATIONS FROM TAFB AND SAB. THERE IS STILL SOME NORTHERLY SHEAR IMPACTING THE CYCLONE...AS SEEN IN THE UW-CIMSS SATELLITE ANALYSIS AND THE SOUTHWARD TILT WITH HEIGHT OF THE CIRCULATION CENTER IN THE AMSR-E IMAGERY. AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT WILL BE INVESTIGATING GERT LATER THIS MORNING AND WILL PROVIDE A BETTER ASSESSMENT OF ITS INTENSITY. THE TROPICAL STORM APPEARS TO HAVE TURNED TO THE NORTH DURING THE PAST 6 HOURS...AND THE LATEST INITIAL MOTION ESTIMATE IS 355/12. GERT IS FORECAST TO TURN NORTH-NORTHEASTWARD AND THEN NORTHEASTWARD AND GAIN FORWARD SPEED DURING THE NEXT FEW DAYS AS IT BECOMES EMBEDDED IN THE STRONGER FLOW TO THE EAST OF A DEEP-LAYER TROUGH MOVING OFFSHORE OF THE UNITED STATES EAST COAST. THE OFFICIAL FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS ONE AND IS NEAR THE MULTI-MODEL CONSENSUS. SOME ADDITIONAL INTENSIFICATION OF GERT APPEARS LIKELY DURING THE NEXT 24 HOURS AS IT REMAINS OVER RELATIVELY WARM WATER AND BENEATH AN UPPER-LEVEL ANTICYCLONE. AFTER 24 HOURS...GERT IS FORECAST TO MOVE OVER WATERS COOLER THAN 26C...WHICH SHOULD INDUCE SOME WEAKENING. IN 2 TO 3 DAYS THE STORM IS FORECAST TO MOVE INTO AN ENVIRONMENT OF STRONG SOUTHWESTERLY SHEAR AND WATERS COOLER THAN 20C...WHICH SHOULD RESULT IN EXTRATROPICAL TRANSITION DURING THAT TIME PERIOD. THE GLOBAL MODELS ARE IN AGREEMENT THAT A FRONT WILL ABSORB GERT IN 3 TO 4 DAYS. INTERESTS IN BERMUDA ARE REMINDED NOT TO FOCUS ON THE EXACT FORECAST TRACK OF GERT...AS ONLY A SLIGHT DEVIATION TO THE LEFT DURING THE NEXT 6 TO 12 HOURS COULD BRING STRONG WINDS CLOSE TO...OR OVER...THE ISLAND. FORECAST POSITIONS AND MAX WINDS INIT 15/0900Z 31.3N 63.4W 50 KT 60 MPH 12H 15/1800Z 33.5N 62.9W 55 KT 65 MPH 24H 16/0600Z 36.8N 60.8W 60 KT 70 MPH 36H 16/1800Z 40.3N 57.2W 55 KT 65 MPH 48H 17/0600Z 43.0N 51.5W 50 KT 60 MPH 72H 18/0600Z 48.0N 36.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 19/0600Z...DISSIPATED $$ FORECASTER CANGIALOSI/BRENNAN