000 WTPZ43 KNHC 180253 TCDEP3 TROPICAL DEPRESSION MANUEL DISCUSSION NUMBER 14 NWS NATIONAL HURRICANE CENTER MIAMI FL EP132013 800 PM PDT TUE SEP 17 2013 INFRARED AND MICROWAVE SATELLITE IMAGERY INDICATE THAT THE CONVECTIVE PATTERN ASSOCIATED WITH MANUEL HAS CHANGED LITTLE SINCE THE PREVIOUS ADVISORY...PROBABLY DUE TO THE MODEST EASTERLY DOWNSLOPE FLOW FROM MAZATLAN BRINGING IN DRY AIR FROM THE SIERRA MADRE OCCIDENTAL MOUNTAIN RANGE. ALTHOUGH SOME BANDING FEATURES HAVE DEVELOPED IN THE SOUTHEASTERN QUADRANT...THE INNER-CORE CONVECTION WEST OF MAZATLAN HAS BEEN DECREASING. THE INITIAL INTENSITY REMAINS AT 30 KT BASED ON A BLEND OF SATELLITE INTENSITY ESTIMATES OF T1.0/25 KT FROM SAB...T2.0/30 KT FROM TAFB...AND A UW-CIMSS ADT VALUE OF T2.4/34 KT. MANUEL CONTINUES TO MOVE SLOWLY NORTHWESTWARD...OR 315/05 KT. A SLOW NORTHWESTWARD MOTION IS EXPECTED AS MANUEL MOVES AROUND THE SOUTHWESTERN PERIPHERY OF A NARROW MID-LEVEL RIDGE LOCATED OVER THE SOUTH-CENTRAL UNITED STATES AND NORTHWESTERN MEXICO. BY 48-72 HOURS...A SHORTWAVE TROUGH CURRENTLY OFF OF THE COASTS OF SOUTHERN CALIFORNIA AND NORTHWESTERN BAJA CALIFORNIA IS EXPECTED TO MOVE EASTWARD AND WEAKEN THE RIDGE...CAUSING THE STEERING FLOW TO ALSO WEAKEN. MANUEL IS FORECAST TO TURN WESTWARD AND THEN WEST-SOUTHWESTWARD AND MOVE SLOWLY ACROSS SOUTHERN BAJA AND INTO THE COLD WATERS OF THE EASTERN PACIFIC BY 96 HOURS. THE OFFICIAL FORECAST IS ESSENTIALLY JUST AN UPDATE OF THE PREVIOUS ADVISORY TRACK...AND REMAINS NEAR THE MIDDLE OF THE NHC TRACK GUIDANCE ENVELOPE. MANUEL IS FORECAST TO GRADUALLY STRENGTHEN DURING THE NEXT 48 HOURS WHILE THE CYCLONE REMAINS EMBEDDED IN A LOW VERTICAL WIND SHEAR ENVIRONMENT AND OVER 29C SSTS. BY 48-72 HOURS...THE RUGGED TERRAIN OF SOUTHERN BAJA SHOULD DISRUPT THE CIRCULATION AND BEGIN TO INDUCE GRADUAL WEAKENING. AFTER PASSING OVER SOUTHERN BAJA...MORE RAPID WEAKENING SHOULD OCCUR WITH MANUEL BECOMING A REMNANT LOW BY 96 HOURS AND DISSIPATING BY DAY 5. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY...AND REMAINS SLIGHTLY LOWER THAN THE SHIPS AND LGEM MODELS. IT IS POSSIBLE THAT MANUEL COULD PEAK AT A SLIGHTLY HIGHER INTENSITY BETWEEN 36 AND 48 HOURS. FORECAST POSITIONS AND MAX WINDS INIT 18/0300Z 23.0N 107.7W 30 KT 35 MPH 12H 18/1200Z 23.4N 108.2W 35 KT 40 MPH 24H 19/0000Z 23.9N 109.0W 40 KT 45 MPH 36H 19/1200Z 24.3N 109.6W 45 KT 50 MPH 48H 20/0000Z 24.6N 110.1W 45 KT 50 MPH 72H 21/0000Z 24.5N 111.0W 30 KT 35 MPH...INLAND 96H 22/0000Z 23.9N 111.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 23/0000Z...DISSIPATED $$ FORECASTER STEWART