MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (BAILU) WARNING NR 05// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 12W (BAILU), LOCATED APPROXIMATELY 608 NM SOUTH OF KADENA AB, HAS TRACKED WESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS CONVECTION CONTINUES TO CONSOLIDATE AROUND THE LOW LEVEL CIRCULATION CENTER (LLCC). THE DEEPEST CONVECTION REMAINS SOUTHWEST OF THE LLCC WITH SCATTERED CONVECTION TO THE NORTHEAST. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON A 220600Z HIMAWARI VISIBLE SATELLITE IMAGE, WHICH SHOWS GOOD LOW LEVEL BANDING, PARTIALLY OBSCURED BY THE DEEP CONVECTION. THE INITIAL INTENSITY OF 45 KNOTS HEDGED ABOVE THE DVORAK CURRENT INTENSITY (CI) ESTIMATE OF T2.5 (35 KNOTS) FROM PGTW BASED ON THE IMPROVING STRUCTURE AND THE PREVIOUS 212214Z SATCON ESTIMATE OF 43 KNOTS. ENVIRONMENTAL ANALYSIS SHOWS THAT TS 12W IS EXPERIENCING FAVORABLE (10 TO 15 KNOT) VERTICAL WIND SHEAR. TS 12W ALSO HAS A STRONG EQUATORWARD OUTFLOW CHANNEL AND A MODERATE, BUT DEVELOPING, POLEWARD OUTFLOW CHANNEL. SEA SURFACE TEMPERATURES REMAIN FAVORABLE FOR ADDITIONAL DEVELOPMENT, BETWEEN 29 AND 30 DEGREES CELSIUS. TS 12W IS TRACKING WESTWARD WHILE UNDER THE INFLUENCE OF A SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. IN THE SHORT TERM, TS 12W WILL TRACK NORTHWESTWARD AS THE AFOREMENTIONED STR SHIFTS SLIGHTLY EASTWARD. FAVORABLE SEA SURFACE TEMPERATURES AND VERTICAL WIND SHEAR WILL ALLOW TS 12W TO REACH 65 KNOTS BY TAU 36. BY TAU 48, THE STR WILL BUILD WESTWARD WHICH WILL KEEP TS 12W ON A NORTHWESTWARD TRACK. TS 12W WILL MAKE LANDFALL IN SOUTHERN TAIWAN BEFORE TAU 48 WITH AN INTENSITY OF 75 KNOTS AND WILL MAKE LANDFALL IN CHINA SHORTLY BEFORE TAU 72. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT, WITH ALL MEMBERS INDICATING A NORTHWESTWARD TRACK. HOWEVER, DUE TO THE HIGH UNCERTAINTY IN THE INITIAL POSITION, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. C. AFTER TAU 72, TS 12W WILL CONTINUE TO TRACK NORTHWESTWARD WHILE UNDER THE INFLUENCE OF THE STR. BY THIS TIME, LAND INTERACTION WITH CHINA WILL CAUSE TS 12W TO WEAKEN RAPIDLY. TS 12W WILL DISSIPATE BY TAU 96 AS IT DECREASES IN INTENSITY TO 20 KNOTS. DYNAMIC MODEL GUIDANCE HAS A SPREAD OF 370 NM BY TAU 96. DUE TO THE WIDE SPREAD IN MODEL GUIDANCE BY TAU 96 AND THE HIGH UNCERTAINTY IN THE INITIAL POSITION, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN