WDPN33 PGTW 290300 MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 18W WARNING NR 01// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 290000Z1 AUG 01 TO 010000Z1 SEP 01. A. TROPICAL DEPRESSION (TD) 18W, LOCATED APPROXIMATELY 70 NM EAST-NORTHEAST OF HAINAN ISLAND, HAS TRACKED WEST-NORTHWESTWARD AT 07 KNOTS DURING THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 282330Z8 INFRARED AND VISIBLE SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON CURRENT SATELLITE INTENSITY ESTIMATES OF 25 KNOTS. ANIMATED VISIBLE AND INFRARED SATELLITE IMAGERY DEPICT IMPROVING ORGANIZATION OVER THE PAST 8 HOURS. HOWEVER, IMAGERY SHOWS THAT CONVECTION HAS CYCLED NORTH AND SOUTHWEST OF THE LOW-LEVEL CIRCULATION CENTER, WHICH REMAINS DIFFICULT TO PINPOINT. B. TD 18W IS TRACKING WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE LOW-LEVEL RIDGE TO THE NORTH. THE OBJECTIVE DYNAMIC AIDS (FOUR: JMA GLOBAL SPECTRAL (JGSM), UK-MET OFFICE GLOBAL (EGRR), AVIATION (AVN), AND NOGAPS) ARE IN FAIR AGREEMENT AND INITIALIZE THE SYSTEM SIMILARLY. HOWEVER, THE EGRR AND AVN MODELS OVER-DEVELOP THE SYSTEM AND THE RIDGE EAST OF THE SYSTEM, AND THEREFORE SHOW A MORE POLEWARD-ORIENTED TRACK. THE JGSM AND NOGAPS MODELS INDICATE MORE OF A WESTWARD TRACK, AND MAINTAIN A WEAKER, SMALLER SYSTEM. OUR FORECAST IS BASED ON THE DYNAMIC AIDS CONSENSUS, WHICH AGREES WITH THE COLORADO STATE UNIVERSITY MODEL, THE COUPLED OCEAN-ATMOSPHERE MESOSCALE PREDICTION SYSTEM, AND THE BETA ADVECTION MODELS. C. TD 18W IS EXPECTED TO INTENSIFY SLOWLY THROUGH THE FORECAST PERIOD. D. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZE SYSTEM. FORECAST TEAM: BARLOW/SMITH/MAYER/TON// BT #XXXX NNNN