WDPN31 PGTW 151500 MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 18W /WARNING NR 07// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 151200Z9 TO 181200Z2 AUG 2004. A. TROPICAL DEPRESSION (TD) 18W, LOCATED APPROXIMATELY 540 NM SOUTHEAST OF OKINAWA, JAPAN, HAS TRACKED WEST-NORTHWESTWARD AT 17 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 151130Z1 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 25 KNOTS. B. TD 18W IS CONTINUING ALONG A WEST-NORTHWESTWARD TRACK AS THE STEERING RIDGE TO THE EAST STRENGTHENS AND BUILDS WESTWARD. RECENT ANIMATED INFRARED IMAGERY INDICATES THAT THE BROAD LOW LEVEL CIRC- ULATION CENTER (LLCC) IS BEGINNING TO CONSOLIDATE, THOUGH IT STILL SHOWS AN EXTENDED AREA OF CONVERGENCE TO THE NORTHEAST. TD 18W IS FORECAST TO CONTINUE TO TRACK ALONG THE SOUTHERN PERIPHERY OF THE STEERING RIDGE LOCATED TO THE NORTHEAST. THE AVAILABLE DYNAMIC AIDS, CONSISTING OF NOGAPS, COAMPS, AFWA MM5, UKMET EGRR, NCEP GFS AND WBAR ARE IN FAIR AGREEMENT WITH THIS SCENARIO, THOUGH NCEP GFS AND UKMET EGRR TURN THE TRACK POLEWARD TOWARD A WEAKNESS IN THE SUBTROPICAL RIDGE AT THE END OF THE FORECAST PERIOD THAT IS NOT REFLECTED IN THE OTHER NUMERICAL MODELS. THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC AIDS. C. TD 18W IS FORECAST TO INTENSIFY AT A LESS THAN CLIMATOLOGICAL RATE IN A MARGINALLY FAVORABLE ENVIRONMENT, ASSUMING THAT THE OTHER- WISE LOOSELY ORGANIZED AND BROAD LLCC CONTINUES CONSOLIDATING INTO A DEFINITIVE CIRCULATION CENTER. MODERATE EQUATORWARD OUTFLOW COULD AID IN POSSIBLE INTENSIFICATION. TD 18W IS EXPECTED TO REMAIN IN AN ENVIRONMENT OF WEAK TO MODERATE VERTICAL WIND SHEAR AND MODERATE UPPER LEVEL OUTFLOW THROUGHOUT THE FORECAST PERIOD. D. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZED SYSTEM. 3. FORECAST TEAM: DIXON/BOWER/MENEBROKER/FUNK// NNNN