WDPN31 PGTW 080300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (HAGUPIT) WARNING NR 29// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 22W (HAGUPIT), LOCATED APPROXIMATELY 126 NM SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS FRAGMENTED BANDING ALONG THE NORTHERN HALF OF THE SYSTEM. THE 2346Z SSMIS MICROWAVE IMAGE REVEALS A CUSP FEATURE PARTIALLY SURROUNDING A TIGHTLY-WRAPPED LOW-LEVEL CIRCULATION CENTER (LLCC). THE CURRENT POSITION IS BASED ON THE MSI ANIMATION AND THE AFOREMENTIONED MICROWAVE IMAGE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 60 KNOTS IS BASED ON AN OVERALL ASSESSMENT OF DVORAK CURRENT INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES AND THE CURRENT OVERALL STRUCTURE. UPPER-LEVEL ANALYSIS INDICATES TS 22W REMAINS IN AN AREA OF MODERATE (10 TO 20 KNOT) VERTICAL WIND SHEAR OFFSET BY A ROBUST POLEWARD OUTFLOW CHANNEL TAPPING INTO THE MID- LATITUDE WESTERLIES. TS 22W IS CURRENTLY TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 22W WILL CONTINUE TO TRACK WEST-NORTHWESTWARD OVER THE NEXT 36 HOURS UNDER THE STEERING INFLUENCE OF THE STR TO THE NORTHEAST. BY TAU 36, TS 22W IS FORECAST TO EMERGE INTO THE SOUTH CHINA SEA (SCS). NEAR TAU 48, TS HAGUPIT IS EXPECTED TO SHIFT WEST- SOUTHWESTWARD AS RIDGING BUILDS IN NORTH OF THE SYSTEM ACROSS THE SCS. TS HAGUPIT WILL CONTINUE ITS WEAKENING TREND ACROSS THE SCS AS IT INTERACTS WITH THE COOLER, MORE STABLE AIR ASSOCIATED WITH THE NORTHEASTERLY SURGE EVENT. C. IN THE EXTENDED TAUS, TS HAGUPIT IS EXPECTED TO MAINTAIN A WEST-SOUTHWESTWARD TRAJECTORY. THE SYSTEM WILL WEAKEN RAPIDLY AS IT APPROACHES THE SOUTHERN COAST OF VIETNAM. WITH THE EXCEPTION OF HWRF, MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT, LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS.// NNNN