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#640509 (Received by flhurricane at: 10:44 AM 23.Oct.2013) TCDAT3 TROPICAL STORM LORENZO DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132013 1100 AM AST WED OCT 23 2013 VISIBLE SATELLITE IMAGES SHOW A STRONGLY SHEARED TROPICAL CYCLONE...WITH THE MAIN AREA OF DEEP CONVECTION DISPLACED WELL TO THE SOUTHEAST OF THE LOW-LEVEL CENTER OF CIRCULATION BY STRONG UPPER-LEVEL NORTHWESTERLY WINDS. BASED ON A BLEND OF DVORAK T- AND CI-NUMBERS...THE INTENSITY IS REDUCED TO 40 KT FOR THIS ADVISORY. DYNAMICAL GUIDANCE INDICATES THAT THE SHEAR WILL RELAX BRIEFLY IN 24-36 HOURS AS AN UPPER-LEVEL ANTICYCLONE SHIFTS EASTWARD AND COMES IN PHASE WITH LORENZO. BY THAT TIME HOWEVER...IT IS ANTICIPATED THAT THE TROPICAL CYCLONE WILL HAVE WEAKENED SO MUCH THAT IT WILL BE UNABLE TO TAKE ADVANTAGE OF THESE CONDITIONS. THE OFFICIAL FORECAST...LIKE THE PREVIOUS ONE...CALLS FOR THE SYSTEM TO DEGENERATE INTO A REMNANT LOW BY 48 HOURS AND TO DISSIPATE COMPLETELY THEREAFTER. THIS IS ALSO SHOWN BY MOST OF THE NUMERICAL GUIDANCE. THE FORWARD MOTION HAS SLOWED SOMEWHAT AND THE CYCLONE IS NOW MOVING EASTWARD NEAR 5 KT. LORENZO IS CURRENTLY MOVING ALONG THE NORTHERN SIDE OF A LOW- TO MID-LEVEL RIDGE. ASIDE FROM THE SLOWER MOTION...THE TRACK FORECAST AND REASONING ARE MOSTLY THE SAME. GLOBAL MODELS SHOW A LOW- TO MID-LEVEL RIDGE BUILDING TO THE EAST OF LORENZO DURING THE NEXT DAY OR TWO. THIS...ALONG WITH FLOW AHEAD OF AN APPROACHING COLD FRONT...SHOULD CAUSE LORENZO OR ITS REMNANT LOW TO TURN NORTHEASTWARD. THE OFFICIAL TRACK FORECAST IS CLOSE TO THE LATEST DYNAMICAL MODEL CONSENSUS...TVCN. FORECAST POSITIONS AND MAX WINDS INIT 23/1500Z 29.5N 49.0W 40 KT 45 MPH 12H 24/0000Z 29.9N 48.1W 35 KT 40 MPH 24H 24/1200Z 30.5N 47.5W 30 KT 35 MPH 36H 25/0000Z 31.5N 46.5W 30 KT 35 MPH 48H 25/1200Z 32.7N 44.8W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 26/1200Z...DISSIPATED $$ FORECASTER PASCH |