ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM POST-TROPICAL CYCLONE OCTAVE DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP152013 200 PM PDT TUE OCT 15 2013 OCTAVE HAS MOVED MUCH FASTER THAN PREVIOUSLY EXPECTED...AND THE CENTER OF THE SYSTEM IS NOW LOCATED OVER MAINLAND MEXICO. THE ROUGH TERRAIN OF THE SIERRA MADRE OCCIDENTAL MOUNTAINS...COUPLED WITH VERTICAL SHEAR OF 40 KT...HAS WEAKENED AND DISPLACED THE REMAINING MODERATE CONVECTION MORE THAN 150 NMI NORTHEAST OF THE CENTER. AS A RESULT...OCTAVE NO LONGER MEETS THE CRITERIA OF A TROPICAL CYCLONE...AND THE SYSTEM HAS BEEN DOWNGRADED TO A POST-TROPICAL REMNANT LOW. THEREFORE...THIS IS THE LAST NHC ADVISORY ON THIS SYSTEM. THE LOW-LEVEL CIRCULATION HAS FINALLY SEPARATED FROM THE MID- AND UPPER-LEVEL CIRCULATIONS. THE LATTER FEATURES AND ASSOCIATED MOISTURE SHOULD CONTINUE NORTHEASTWARD ACROSS NORTHERN MEXICO AND THE UNITED STATES SOUTHERN PLAINS...ENHANCING RAINFALL ACROSS THOSE REGIONS FOR THE NEXT COUPLE OF DAYS. INTERESTS IN THOSE AREAS SHOULD MONITOR RAINFALL STATEMENTS FROM YOUR LOCAL WEATHER SERVICE OFFICE. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 26.9N 109.4W 20 KT 25 MPH 12H 16/0600Z...DISSIPATED $$ FORECASTER STEWART NNNN