000 WTPZ42 KNHC 231632 TCDEP2 TROPICAL DEPRESSION SEVENTEEN-E SPECIAL DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP172008 915 AM PDT THU OCT 23 2008 SATELLITE IMAGERY AND RECENT MICROWAVE IMAGERY FROM SSMI AND QUIKSCAT INDICATE THAT THE AREA OF DISTURBED WEATHER A FEW HUNDRED MILES SOUTH OF MANZANILLO MEXICO HAS ACQUIRED SUFFICIENT ORGANIZATION TO BE CLASSIFIED AS A TROPICAL DEPRESSION. DVORAK CLASSIFICATIONS AT 1200 UTC FROM TAFB AND SAB SUPPORT AN INITIAL INTENSITY OF 30 KT. A 1324 UTC QUIKSCAT PASS SHOWING SOME RELIABLE 20-25 KT RETRIEVALS OUTSIDE OF THE DEEP CONVECTION SOUTH AND EAST OF THE CENTER IS ALSO CONSISTENT WITH SLIGHTLY HIGHER WINDS IN THE CONVECTION. THEREFORE THE INITIAL INTENSITY IS SET TO 30 KT. A QUIKSCAT AMBIGUITY ANALYSIS...ALONG WITH A SSMI PASS FROM 1239 UTC...SUGGESTS THAT THE BROAD SURFACE CENTER IS LOCATED SOUTHEAST OF THE DEEP CONVECTION DUE TO ABOUT 15-20 KT OF SOUTHEASTERLY SHEAR ANALYZED BY CIMSS AT THE UNIVERSITY OF WISCONSIN. THE DEPRESSION IS EXPECTED TO CONTINUE TO MOVE NORTHWARD FOR THE NEXT DAY OR TWO UNTIL IT BECOMES DECOUPLED FROM THE DEEP-LAYER FLOW AND IS STEERED BY THE LOW-LEVEL RIDGE...WHICH WILL INDUCE A MORE WESTWARD MOTION UNTIL DISSIPATION. THE DEPRESSION HAS A SHORT WINDOW IN WHICH TO INTENSIFY BEFORE A STRONG UPPER-LEVEL TROUGH DIGGING INTO THE REGION ON FRIDAY INCREASES THE VERTICAL SHEAR TO OVER 40 KNOTS. THIS WILL LIKELY RESULT IN THE LOW-LEVEL CENTER BECOMING DECOUPLED FROM THE DEEP CONVECTION. THE INTENSITY FORECAST SHOWS SLIGHT INTENSIFICATION TO A MINIMAL TROPICAL STORM TONIGHT...FOLLOWED BY SLOW WEAKENING AND DEGENERATION INTO A REMNANT LOW AFTER 72 HOURS. FORECAST POSITIONS AND MAX WINDS INITIAL 23/1615Z 13.1N 104.9W 30 KT 12HR VT 24/0000Z 13.9N 104.9W 35 KT 24HR VT 24/1200Z 15.0N 104.9W 35 KT 36HR VT 25/0000Z 16.3N 105.3W 30 KT 48HR VT 25/1200Z 17.2N 106.3W 25 KT 72HR VT 26/1200Z 17.5N 109.0W 20 KT...REMNANT LOW 96HR VT 27/1200Z 17.5N 112.0W 20 KT...REMNANT LOW 120HR VT 28/1200Z...DISSIPATED $$ FORECASTER BRENNAN/BEVEN