MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 07W (SEVEN) WARNING NR 001// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 07W (SEVEN), LOCATED APPROXIMATELY 204 NM NORTHWEST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS CONSOLIDATING, DEEP CONVECTION OBSCURING A LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE LOW LEVEL FEATURES PRESENT IN A 091015Z WINDSAT 37GHZ IMAGE AND THE CIRCULATION PRESENT IN THE COMPOSITE RADAR LOOP. THE INITIAL INTENSITY OF 30 KTS IS PLACED WITH FAIR CONFIDENCE BASED ON A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T1.0 (25 KTS) AND THE 30 KTS WINDS PRESENT IN THE ELONGATED AND ASYMMETRIC WIND FIELD REFLECTED IN A 091202Z ASCAT-A PASS. TD 07W IS TRACKING NORTHWARD ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) AND THROUGH A MARGINALLY FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH WARM (30-31 CELSIUS) SEA SURFACE TEMPERATURES (SST) AND MODERATE EQUATORWARD AND POLEWARD OUTFLOW ALOFT OFFSET BY MODERATE (10-15 KTS) VERTICAL WIND SHEAR (VWS). 3. FORECAST REASONING. A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE AND SETS THE FORECAST PHILOSOPHY. B. TD 07W IS FORECAST TO CONTINUE TRACKING NORTHWARD ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE POSITIONED TO THE EAST AS IT TRACKS TOWARDS THE TAIWAN STRAIT. CONTINUED WARM (29-30 CELSIUS) SSTS WILL SUPPORT INTENSIFICATION TO 35 KTS BY TAU 12 AND TO A MAXIMUM INTENSITY OF 40 KTS BY TAU 24, HOWEVER THE ENVIRONMENT WILL BECOME INCREASINGLY UNFAVORABLE DURING THIS TIME WITH INCREASING VWS AND CONVERGENT FLOW FROM AN INDUCED UPPER LEVEL TROUGH POSITIONED OVER THE TAIWAN STRAIGHT. THIS CONVERGENCE AND HIGH (25-30 KTS) VWS WILL HINDER INTENSIFICATION AND LEAD TO GRADUAL WEAKENING TO 35 KTS BY TAU 36 AS THE SYSTEM BEGINS DISSIPATION OVER WATER. TD 07W WILL MAKE LANDFALL OVER MAINLAND CHINA AFTER TAU 36 WHEREUPON IT WILL WEAKEN DUE TO THE FRICTIONAL EFFECTS OF LAND AND DISSIPATE OVER LAND BY TAU 48. THERE IS A LARGE SPREAD IN NUMERICAL MODEL SOLUTIONS WITH A 200 NM CROSS TRACK SPREAD IN POSITIONS AT TAU 48. THIS LARGE SPREAD OF THE CROSS TRACK NUMERICAL MODEL SOLUTIONS LENDS ONLY FAIR CONFIDENCE TO THE OVERALL JTWC FORECAST TRACK.// NNNN NNNN