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#636657 (Received by flhurricane at: 10:57 PM 05.Oct.2013) TCDAT2 TROPICAL DEPRESSION KAREN DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122013 1000 PM CDT SAT OCT 05 2013 KAREN HAS ESSENTIALLY REMAINED STATIONARY FOR THE LAST SEVERAL HOURS AND THAT LACK OF MOTION...COUPLED WITH INCREASING UPPER-LEVEL WINDS AHEAD OF AN EASTWARD-MOVING DEEP-LAYER TROUGH...HAS INCREASED THE SHEAR SIGNIFICANTLY ACROSS THE CYCLONE. THE RESULT IS THAT CONVECTION HAS WEAKENED AND BECOME DISPLACED WELL TO THE EAST AND SOUTHEAST OF THE LOW-LEVEL CIRCULATION CENTER. SATELLITE CLASSIFICATIONS FROM TAFB SUPPORTED KEEPING KAREN AS A BORDERLINE TROPICAL STORM AT 00Z...BUT THE LACK OF CONVECTION NEAR THE CENTER SINCE THEN REQUIRES A DOWNGRADE TO DEPRESSION STATUS AT THE 03Z ADVISORY TIME. GIVEN THAT THE VERTICAL WIND SHEAR IS FORECAST TO GET EVEN STRONGER OVER THE NEXT 2 DAYS...RE-STRENGTHENING BACK TO TROPICAL STORM STATUS IS NOT LIKELY...ESPECIALLY SINCE THE MID-LEVELS OF THE TROPOSPHERE WILL BECOME INCREASINGLY DRIER AS WELL...PREVENTING THE RE-DEVELOPMENT OF DEEP CONVECTION OVER THE CENTER. AS A RESULT...TROPICAL STORM WARNINGS HAVE BEEN DISCONTINUED. THE STATIONARY MOTION OF KAREN THE PAST 6-9 HOURS HAS BEEN DUE TO A NORTHWEST-TO-SOUTHEAST ORIENTED MID-/UPPER-LEVEL RIDGE LOCATED ACROSS FLORIDA AND THE SOUTHEASTERN UNITED STATES...WHICH HAS BLOCKED ANY EASTWARD MOTION BY THE CYCLONE. THIS BLOCKING PATTERN IS EXPECTED TO SHIFT SLOWLY EASTWARD OVER THE NEXT TWO DAYS... ALLOWING KAREN OR ITS REMNANTS TO MOVE IN A EASTWARD TO EAST-NORTHEASTWARD DIRECTION UNTIL THE CYCLONE DISSIPATES IN 48-72 HOURS OR IS ABSORBED BY AN APPROACHING FRONTAL SYSTEM. THE NHC FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND THE CONSENSUS MODEL TVCA...AND SHOWS KAREN PASSING NEAR OR OVER THE EXTREME SOUTHEASTERN TIP OF LOUISIANA IN ABOUT 24 HOURS...AND REMAINING JUST OFFSHORE OF THE NORTHERN GULF COAST AFTER THAT. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 28.1N 91.9W 30 KT 35 MPH 12H 06/1200Z 28.7N 90.7W 30 KT 35 MPH 24H 07/0000Z 29.1N 88.4W 30 KT 35 MPH 36H 07/1200Z 29.3N 86.1W 30 KT 35 MPH...POST-TROP/REMNT LOW 48H 08/0000Z 29.5N 83.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 09/0000Z...DISSIPATED $$ FORECASTER STEWART |