WDPN32 PGTW 201500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (BOLAVEN) WARNING NR 03// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 16W (BOLAVEN), LOCATED APPROXIMATELY 400 NM SOUTH OF IWO TO, JAPAN, HAS TRACKED NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER WITH IMPROVED CONVECTIVE BANDING WRAPPING INTO THE CENTER. A 201016Z SSMIS IMAGE SHOWS THAT THE BULK OF THE DEEP CONVECTION IS CONFINED TO THE SOUTHERN SEMI-CIRCLE; HOWEVER, TIGHTLY-WRAPPED SHALLOW CONVECTIVE BANDING IS EVIDENT OVER THE NORTHERN SEMI-CIRCLE. THE INITIAL INTENSITY REMAINS ASSESSED AT 35 KNOTS BASED ON DVORAK ESTIMATES OF 35 KNOTS FROM ALL AGENCIES. THE INITIAL POSITION IS BASED ON RECENT IR IMAGERY AS WELL AS A 200917Z TRMM 37H GHZ IMAGE, WHICH SHOWED A WEAK MICROWAVE EYE FEATURE. UPPER-LEVEL ANALYSIS SHOWS A FAVORABLE ENVIRONMENT WITH RADIAL OUTFLOW ENHANCED BY A TUTT CELL NEAR 35N 170E. TS 16W IS TRACKING NORTHWESTWARD ALONG THE WESTERN PERIPHERY OF A LOW- TO MID-LEVEL STEERING RIDGE. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 16W IS FORECAST TO TURN WEST-NORTHWESTWARD IN THE NEXT 12- 24 HOURS AS IT TRANSITIONS TO THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE (STR) POSITIONED SOUTH OF JAPAN. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT WITH A 130 NM SPREAD IN GUIDANCE AT TAU 72. ADDITIONALLY, THE 20/00Z UPPER-AIR DATA FROM BOTH RJAO AND ROMD INDICATE EAST-SOUTHEASTERLY FLOW IN THE MID-LEVELS, SUPPORTING THE JTWC TRACK FORECAST. TS 16W IS EXPECTED TO INTENSIFY THROUGH THE PERIOD UNDER FAVORABLE ENVIRONMENTAL CONDITIONS. C. AFTER TAU 72, TS 16W IS FORECAST TO TRACK SLIGHTLY MORE POLEWARD AS THE SYSTEM TRACKS ALONG THE SOUTHWEST PERIPHERY OF THE SUBTROPICAL RIDGE AND A MIDLATITUDE TROUGH DEEPENS OVER EASTERN CHINA. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT WITH A 160 NM SPREAD AT TAU 120 ALTHOUGH THERE ARE SIGNIFICANT DIFFERENCES IN TRACK SPEED. ALTHOUGH THERE IS A FAIRLY TIGHT GROUPING OF MODEL GUIDANCE, THE JTWC FORECAST FAVORS THE ECMWF AND JGSM MODELS, WHICH ARE ON THE SOUTHERN EDGE OF THE AIDS ENVELOPE AND INDICATE A TRACK SOUTH OF OKINAWA. THE BULK OF THE ENSEMBLE DATA ALSO SUPPORTS A TRACK SOUTH OF OKINAWA. THERE IS HIGH CONFIDENCE IN THIS FORECAST TRACK; HOWEVER, THERE IS ALSO A POSSIBILITY THAT THE SYSTEM COULD TRACK CLOSER TO OKINAWA AS SUGGESTED BY NOGAPS, GFS AND UKMO.// NNNN