000 WTNT42 KNHC 031438 TCDAT2 TROPICAL STORM KAREN DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122013 1000 AM CDT THU OCT 03 2013 KAREN CONTINUES TO HAVE A SOMEWHAT SHEARED APPEARANCE ON SATELLITE IMAGERY...WITH THE DEEP CONVECTION DISPLACED TO THE NORTHEAST OF THE LOW-LEVEL CENTER. THIS IS CONSISTENT WITH THE 20 OR SO KT OF SHEAR ANALYZED OVER THE CYCLONE BY THE SHIPS MODEL. THE INITIAL INTENSITY IS RAISED TO 55 KT BASED ON SEVERAL BIAS-CORRECTED SFMR WINDS IN THE 50-55 KT RANGE REPORTED BY THE AIRCRAFT. WITH MODERATE SHEAR EXPECTED TO CONTINUE...ONLY GRADUAL STRENGTHENING IS EXPECTED BEFORE THE SHEAR INCREASES FURTHER IN ABOUT 48 HOURS. SOME WEAKENING IS ANTICIPATED AS KAREN APPROACHES THE GULF COAST...BUT THE STORM COULD STILL BE NEAR HURRICANE STRENGTH AT LANDFALL. THE NHC FORECAST IS CLOSE TO THE SHIPS AND LGEM MODELS THROUGH THE PERIOD. KAREN SHOULD BE INVOLVED WITH A FRONTAL ZONE BY DAY 4 AND ABSORBED BY THE FRONT BY DAY 5. THE INITIAL MOTION ESTIMATE IS STILL A RELATIVELY UNCERTAIN 330/10. THE TRACK FORECAST REASONINS HAS NOT CHANGED...AS KAREN WILL MOVE AROUND THE PERIPHERY OF THE SUBTROPICAL RIDGE DURING THE NEXT DAY OR SO AND THEN ACCELERATE NORTHEASTWARD AHEAD OF A MID/UPPER-LEVEL TROUGH. THERE REMAINS CONSIDERABLE EAST/WEST SPREAD IN THE TRACK GUIDANCE...WITH THE GFS REMAINING WELL EAST OF THE OTHER GLOBAL MODELS AND ITS ENSEMBLE MEAN. THE TRACK GUIDANCE HAS SHIFTED A LITTLE TO THE WEST THIS CYCLE...AND THE NEW NHC TRACK IS CLOSE TO THE MULTI-MODEL CONSENSUS AND ABOUT A HALF A DEGREE LEFT OF THE PREVIOUS TRACK THROUGH 48 HOURS. NOTE THAT A STRONGER STORM WOULD LIKELY MOVER FARTHER EAST...WHILE A WEAKER SYSTEM WOULD BE MORE LIKELY TO TAKE A TRACK FARTHER WEST. FORECAST POSITIONS AND MAX WINDS INIT 03/1500Z 22.2N 87.9W 55 KT 65 MPH 12H 04/0000Z 23.8N 88.7W 60 KT 70 MPH 24H 04/1200Z 25.4N 89.4W 60 KT 70 MPH 36H 05/0000Z 26.9N 89.5W 65 KT 75 MPH 48H 05/1200Z 28.2N 89.1W 60 KT 70 MPH 72H 06/1200Z 31.0N 87.0W 45 KT 50 MPH...INLAND 96H 07/1200Z 35.0N 81.5W 25 KT 30 MPH...POST-TROP/EXTRATROP 120H 08/1200Z...ABSORBED BY FRONT $$ FORECASTER BRENNAN