ZCZC MIATCDAT2 ALL TTAA00 KNHC DDHHMM TROPICAL STORM KAREN SPECIAL DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122013 800 AM CDT THU OCT 03 2013 AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING THE AREA OF LOW PRESSURE JUST NORTH OF THE YUCATAN PENINSULA FOUND A CLOSED CIRCULATION WITH A CENTRAL PRESSURE OF 1004 MB AND SURFACE WINDS AROUND 50 KT. BASED ON THESE DATA...ADVISORIES ARE BEING INITIATED ON TROPICAL STORM KAREN. MOST OF THE DEEP CONVECTION IS DISPLACED NORTH AND EAST OF THE CENTER DUE TO MODERATE SOUTHWESTERLY SHEAR. THE SHEAR IS EXPECTED TO CONTINUE AND THE INTENSIFY IN 2 TO 3 DAYS. THIS ENVIRONMENT SHOULD ONLY SUPPORT GRADUAL INTENSIFICATION DURING THE NEXT DAY OR SO...WITH SOME WEAKENING EXPECTED AS KAREN APPROACHES THE GULF COAST...BUT THE STORM COULD STILL BE NEAR HURRICANE STRENGTH AT LANDFALL. THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 340/11 GIVEN THE RECENT FORMATION OF THE CENTER. KAREN IS EXPECTED TO GRADUALLY TURN NORTHWARD AROUND THE PERIPHERY OF A MID-LEVEL RIDGE AND THEN ACCELERATE NORTHEASTWARD LATE IN THE PERIOD AHEAD OF A MID/UPPER-LEVEL TROUGH. ALL OF THE TRACK GUIDANCE IS IN AGREEMENT ON THIS GENERAL SCENARIO...HOWEVER THERE IS SIGNIFICANT WEST/EAST SPREAD IN THE TRACKS...WITH THE ECMWF ON THE WEST SIDE OF THE GUIDANCE ENVELOPE AND THE GFS FARTHEST EAST. THE NHC TRACK FORECAST IS NEAR THE MIDDLE OF THE GUIDANCE ENVELOPE AND THE TVCA MULTI-MODEL CONSENSUS THROUGH LANDFALL. NOTE THAT A TRACK FARTHER EAST WOULD LIKELY RESULT IN A STRONGER STORM...WHILE KAREN WOULD LIKELY BE WEAKER IF IT TAKES A TRACK FARTHER WEST. GIVEN THE FORECAST...HURRICANE AND TROPICAL STORM WATCHES HAVE BEEN ISSUED FOR PORTIONS OF THE NORTHERN GULF COAST. FORECAST POSITIONS AND MAX WINDS INIT 03/1300Z 22.0N 87.6W 50 KT 60 MPH 12H 03/1800Z 23.4N 88.2W 55 KT 65 MPH 24H 04/0600Z 25.4N 88.8W 60 KT 70 MPH 36H 04/1800Z 27.0N 88.9W 65 KT 75 MPH 48H 05/0600Z 28.3N 88.7W 60 KT 70 MPH 72H 06/0600Z 31.0N 87.5W 50 KT 60 MPH...INLAND 96H 07/0600Z 34.5N 83.0W 25 KT 30 MPH...POST-TROP/EXTRATROP 120H 08/0600Z 38.5N 77.5W 20 KT 25 MPH...POST-TROP/EXTRATROP $$ FORECASTER BRENNAN NNNN