MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (NINE) WARNING NR 05// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 09W (NINE), LOCATED APPROXIMATELY 82 NM EAST- SOUTHEAST OF ANDERSEN AFB, GUAM HAS TRACKED WEST-NORTHWESTWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS FORMATIVE DEEP CONVECTIVE BANDING SURROUNDING A SMALL, TIGHTLY COMPACT LOW-LEVEL CIRCULATION CENTER (LLCC). A 111132Z METOP-A MICROWAVE IMAGE REVEALS THE CONSOLIDATED STRUCTURE OF THE TIGHTLY WRAPPED LLCC WITH BANDING FEATURES WRAPPING TO THE CENTER. THE INITIAL POSITION IS BASED ON THE EIR ANIMATION AND ABOVE MICROWAVE IMAGE WITH FAIR CONFIDENCE. THE INITIAL INTENSITY HAS REMAINED AT 35 KNOTS BASED ON CURRENT STRUCTURE AS WELL AS DVORAK INTENSITY ESTIMATE ASSESSMENT FROM ALL REPORTING AGENCIES. UPPER-LEVEL ANALYSIS CONTINUES TO INDICATE A FAVORABLE ENVIRONMENT CHARACTERIZED BY WEAK (05 TO 10 KNOTS) VERTICAL WIND SHEAR AND STRONG RADIAL OUTFLOW, AS EVIDENT IN THE WATER VAPOR IMAGERY. TS 09W IS CURRENTLY TRACKING WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF THE DEEP-LAYER SUBTROPICAL RIDGE (STR) ANCHORED TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST TRACK PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. HOWEVER, THE INTENSITY FORECAST HAS SLIGHTLY DECREASED DUE TO THE SLOW ORGANIZATION AND AN OVERALL DECREASE IN OBJECTIVE AID INTENSITY GUIDANCE. B. TS 09W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWEST THROUGH THE NEXT 72 HOURS ALONG THE SOUTHERN PERIPHERY OF THE STR. FAVORABLE CONDITIONS OF LOW VWS, WARM SEA SURFACE TEMPERATURE, AND STRONG OUTFLOW ARE EXPECTED TO PERSIST THROUGH THE FORECAST PERIOD. THE SYSTEM IS FORECAST TO INTENSIFY TO TYPHOON STRENGTH AT TAU 36. C. AFTER TAU 72, A MID-LATITUDE SHORTWAVE TROUGH IS FORECAST TO DIG IN FROM EASTERN CHINA AND MODIFY THE STEERING RIDGE. THIS MODIFICATION OF THE RIDGE WILL SLOW TS 09W AND BEGIN TO SLOWLY DRIVE THE SYSTEM POLEWARD. THE COMBINED EFFECTS OF FAVORABLE SST AND UPPER- LEVEL CONDITIONS WILL ENHANCE FURTHER INTENSIFICATION FOR THE REMAINDER OF THE FORECAST. THE AVAILABLE MODEL GUIDANCE IS IN GOOD AGREEMENT; HOWEVER, DUE TO THE INITIAL POSITIONING AND TRACK SPEEDS UNCERTAINTY, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST.// NNNN NNNN