WDPN31 PGTW 200300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (DUJUAN) WARNING NR 012// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 01W (DUJUAN), LOCATED APPROXIMATELY 85 NM NORTHWEST OF SONSOROL, PHILIPPINES, HAS TRACKED NORTHEASTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A LARGE CONVECTIVE MASS SHEARED NORTHWEST AWAY FROM A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) DUE TO STRONG LOW VERTICAL WIND SHEAR (LWS). THE INITIAL INTENSITY HAS DECREASED OVER THE PAST SIX HOURS AND IS NOW 35 KNOTS WITH FAIR CONFIDENCE, HEDGED SLIGHTLY HIGHER THAN MULTIPLE AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T2.0 (30 KTS) FROM PGTW, RJTD, AND ADVANCED DVORAK TECHNIQUE (ADT) ESTIMATE OF T2.0 (30 KTS), MORE IN LINE WITH KNES OF T2.5 (35 KTS). ENVIRONMENTAL AND SATELLITE ANALYSIS SHOWS POLEWARD OUTFLOW AND WARM 29-30C SSTS; HOWEVER, THE STRONG (25-30 KT) EASTERLY VWS HAS ERODED THE SYSTEM STRUCTURE AND DECOUPLED THE UPPER AND LOWER-LEVEL PORTIONS OF THE SYSTEM. TS 01W IS TRACKING ALONG THE SOUTHWEST PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE IN THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 01W IS MOVING SLOWLY NORTHWESTWARD, AS THE STR CENTERED TO THE EAST-NORTHEAST BEGINS TO BUILD IN FROM THE EAST. TS DUJUAN WILL MOVE ALONG THE WEST SIDE OF THE STR WITH A NORTHWEST-SOUTHEAST ORIENTATION. THE SYSTEM IS FORECAST TO TRACK NORTHEAST OF MINDANAO AND MAKE LANDFALL NEAR LEYTE BETWEEN TAU 36 AND 48, THEN CONTINUE TO TRACK OVER THE CENTRAL PHILIPPINE ISLANDS. THE SYSTEM CONTINUES TO BE IMPEDED BY STRONG VWS AND WILL ENCOUNTER TERRAIN FRICTIONAL EFFECTS ONCE LANDFALL OCCURS AND BEGIN THE DISSIPATION BY TAU 72. NUMERICAL MODEL GUIDANCE IS DECREASING IN OVERALL AGREEMENT WITH 275NM SPREAD AT TAU 36, INCREASING TO 420NM AT TAU 72. UKMET REMAINS A FAR RIGHT OUTLIER AND ECMWF IS FAR LEFT OF MODEL CONSENSUS. THIS SPREAD IN MODEL GUIDANCE LENDS TO OVERALL POOR CONFIDENCE IN THE JTWC FORECAST TRACK FROM TAU 36 THROUGH THE FORECAST PERIOD. C. AFTER TAU 72, THE SYSTEM WILL CONTINUE TO WEAKEN FURTHER AS IT COMES UNDER THE STEERING INFLUENCE OF THE LOWER LEVEL NORTHEASTERLY FLOW. BETWEEN TAU 72 AND 96 THE SYSTEM WILL MOVE INTO THE SOUTH CHINA SEA AND ENCOUNTER A MUCH COOLER AND DRIER AIR MASS, ALONG WITH CONVERGENT UPPER-LEVEL FLOW AND CONTINUE DISSIPATING, FULLLY DISSIPATED OVER WATER BY TAU 96. NUMERICAL MODEL GUIDANCE HAS INCREASED IN DISPARITY IN THE EXTENDED TAUS, WITH THE CONSENSUS MEMBERS. THE JTWC FORECAST TRACK IS POSITIONED CLOSE TO THE MULTI- MODEL CONSENSUS AND CLOSELY TRACKS WITH THE GFS SOLUTION, WITH POOR CONFIDENCE.// NNNN