000 WTPZ42 KNHC 290855 TCDEP2 TROPICAL STORM BARBARA DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP022013 200 AM PDT WED MAY 29 2013 SATELLITE IMAGERY AND RADAR DATA FROM PUERTO ANGEL MEXICO INDICATE THAT THE STRUCTURE OF BARBARA HAS CONTINUED TO INCREASE IN ORGANIZATION OVERNIGHT. THE CENTER IS EMBEDDED IN THE MIDDLE OF A CENTRAL DENSE OVERCAST...COMPRISED OF COLD-TOPPED DEEP CONVECTION. BANDING HAS INCREASED...WITH THE MOST PROMINENT BAND WRAPPING ALMOST ENTIRELY AROUND THE CIRCULATION. MORE RECENTLY...A PARTIAL EYEWALL HAS BEEN NOTED IN RADAR IMAGERY...WITH THE EYEWALL BECOMING INCREASINGLY BETTER DEFINED. DVORAK T-NUMBERS WERE 3.0 FROM TAFB AND 3.5 FROM SAB...AND THE INITIAL INTENSITY HAS THEREFORE BEEN RAISED TO 50 KT. THE INITIAL MOTION IS 035/04. BARBARA HAS BEEN MOVING SLOWLY NORTHEASTWARD AROUND THE NORTHWEST SIDE OF A MID-LEVEL RIDGE OVER THE WESTERN CARIBBEAN SEA. HOWEVER...THE APPROACH OF A TROUGH OVER THE CENTRAL UNITED STATES SHOULD DRAW THE CYCLONE NORTH- NORTHEASTWARD OR NORTHEASTWARD WITH SOME INCREASE IN FORWARD SPEED TODAY. THIS MOTION SHOULD BRING THE CENTER OF THE CYCLONE TO THE COAST IN THE GULF OF TEHUANTEPEC IN THE NEXT 12 TO 18 HOURS. AFTER CROSSING THE COAST...THE WEAKENING CYCLONE SHOULD MOVE NEAR OR WEST OF THE ISTHMUS OF TEHUANTEPEC BEFORE DISSIPATING...WITH AN OUTSIDE CHANCE OF THE REMNANTS ENTERING THE BAY OF CAMPECHE. THE NHC TRACK FORECAST REPRESENTS AN UPDATE OF THE PREVIOUS ONE AND IS CLOSE TO THE GFS AND MULTI-MODEL CONSENSUS. SHEAR ANALYSES FROM UW-CIMSS AND SHIPS MODEL SHOW ONLY LIGHT SHEAR OVER BARBARA AS IT MOVES SLOWLY OVER VERY WARM SSTS AROUND 30C. THESE FAVORABLE ENVIRONMENTAL FACTORS ARE EXPECTED TO REMAIN IN PLACE PRIOR TO LANDFALL. IN ADDITION...AN EARLIER SSMI/S PASS SHOWED A CLOSED LOW-LEVEL RING OF CONVECTION...POSSIBLY A HARBINGER OF A RAPID INTENSIFICATION PHASE ABOUT TO OCCUR. THE LACK OF TIME OVER WATER IS THE MAIN LIMITING FACTOR FOR SIGNIFICANT STRENGTHENING. THE NEW NHC INTENSITY FORECAST IS INCREASED FROM THE PREVIOUS ONE IN THE FIRST 12 HOURS GIVEN CURRENT TRENDS...AND IS CLOSE TO THE SHIPS/LGEM GUIDANCE AND WELL AS THE INTENSITY CONSENSUS AIDS. ALTHOUGH NOT EXPLICITLY FORECAST...THERE IS A POSSIBILITY THAT BARBARA COULD REACH HURRICANE STRENGTH PRIOR TO LANDFALL. FOR THIS REASON...THE GOVERNMENT OF MEXICO HAS ISSUED A HURRICANE WATCH FOR A PORTION OF THE COAST OF THE GULF OF TEHUANTEPEC. DUE TO THE SLOW MOTION OF THIS SYSTEM...AS WELL AS THE MOUNTAINOUS TERRAIN IN AND NEAR THE LANDFALL AREA...HEAVY RAINFALL IS EXPECTED OVER PORTIONS OF SOUTHEASTERN MEXICO...WHICH COULD RESULT IN LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 14.8N 95.6W 50 KT 60 MPH 12H 29/1800Z 15.7N 95.0W 60 KT 70 MPH 24H 30/0600Z 17.0N 94.8W 40 KT 45 MPH...INLAND 36H 30/1800Z 18.0N 94.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 31/0600Z...DISSIPATED $$ FORECASTER KIMBERLAIN/BROWN