WDPN32 PGTW 250300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (SAOLA) WARNING NR 006// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 19.8N 124.1E INITIAL INTENSITY: 55 KTS GEOGRAPHIC REFERENCE: 349 NM SOUTH-SOUTHEAST OF TAIPEI, TAIWAN MOVEMENT PAST 6 HOURS: SOUTHWARD AT 02 KTS SIGNIFICANT WAVE HEIGHT: 17 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A VERY COMPACT, BUT QUICKLY CONSOLIDATING SYSTEM, WITH DEEP PERSISTENT CONVECTION FIRING OFF NEAR THE ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC). THE LATEST ENHANCED INFRARED (EIR) IMAGERY SHOWS VORTICAL HOT TOWERS (VHTS) WITH CLOUD TOP TEMPERATURES NEAR -87C EXPLODING DIRECLTY OVER OR NEAR THE LLCC. A 242119Z 91GHZ MICROWAVE IMAGE SHOWED A FAIRLY WELL-FORMED MICROWAVE EYE FEATURE, AND COMPARISON WITH THE 36GHZ IMAGE INDICATES THAT THE PRONOUNCED VORTEX TILT SEEN EARLIER HAS LESSENED, AND THE VORTEX IS NOW FOR THE MOST PART VERITICALLY ALIGNED. THE INITIAL POSITION IS ASSESSED WITH MEDIUM CONFIDENCE DUE TO OBSCURATION OF THE LOW-LEVEL CLOUD LINES BUT SUPPORTED BY EXTRAPOLATION OF THE AFOREMENTIONED MICROWAVE EYE FEATURES. THE INITIAL INTENSITY IS INCREASED TO 55 KNOTS, ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AVERAGE OF THE AGENCY DVORAK CURRENT INTENSITY ESTIMATES AND ANALYSIS OF THE MICROWAVE IMAGERY. OF NOTE, A 250000Z SHIP OBSERVATION LOCATED APPROXIMATELY 55NM TO THE SOUTHEAST OF THE LLCC, INDICATED WESTERLY WINDS OF 40 KNOTS. THE SYSTEM HAS TURNED SLOWLY TOWARDS THE SOUTH OVER THE PREVIOUS 12 HOURS AS THE PRIMARY STEERING INFLUENCE SHIFTS TO THE SUBTROPICAL RIDGE (STR) CENTERED NEAR HONG KONG. ANALYSIS REVEALS A FAVORABLE ENVIRONMENT CHARACTERIZED BY WARM (30-31C) SSTS, HIGH OHC, LOW DEEP-LAYER VERTICAL WIND SHEAR (VWS) AND MODERATE TO STRONG EQUATORWARD OUTFLOW. ANIMATED MULTI-BAND WATER VAPOR IMAGERY SUGGESTS SOME LIGHT NORTHERLY FLOW IMPINGING POLEWARD OUTFLOW AND THE HAFS-A CROSS-SECTIONS INDICATE SUBSIDENCE AND DRY MID-LEVEL AIR IN THIS REGION AS WELL. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: EASTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED NEAR HONG KONG. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.5 - 55 KTS RJTD: T3.0 - 45 KTS RCTP: T3.5 - 55 KTS KNES: T4.0 - 65 KTS CIMSS ADT: 45 KTS AT 242330Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: THERE IS NO SIGNIFICANT CHANGE TO THE OVERALL FORECAST AS COMPARED TO THE PREVIOUS DISCUSSION. BASED ON THE MOST RECENT TRACK MOTION, IT APPEARS THAT THE PRIMARY STEERING INFLUENCE HAS STARTED TO SHIFT OVER TO THE STR TO THE WEST. OVER THE NEXT 12 TO 24 HOURS, THE STR WILL BUILD AND STRENGTHEN THE STEERING GRADIENT AND TS 09W WILL PICK UP SPEED TO A SIZZLING 05 KNOTS, DIVING SOUTH TO THE EAST OF LUZON. BASED ON THE EARLIER THAN EXPECTED TURN SOUTHWARD, THE TRACK NOW LIES A BIT FURTHER OFFSHORE OF LUZON, WHICH WILL HAVE AN IMPACT ON THE ULTIMATE INTENSITY THE SYSTEM CAN OBTAIN. BY TAU 48, THE STR TO THE WEST SLIDES SOUTHWESTWARD AND DISSIPATES AND THE STEERING INFLUENCE SHIFTS TO THE NEAR EQUATORIAL RIDGE (NER) LYING ALONG ABOUT 5N LATITUDE. TS 09W WILL TURN EASTWARD AFTER TAU 48, THEN TURN NORTHWARD BY TAU 72 AS THE STEERING BATON IS HANDED OFF TO THE STRONG SUBTROPICAL RIDGE (STR) FAR TO THE NORTHEAST. THE MOVEMENT WESTWARD OF THIS RIDGE WILL PUSH TS 09W WEST-NORHTWEST INTO THE LUZON STRAIT BY THE END OF THE FORECAST PERIOD. POTENTIAL INTERACTION WITH A VERY LARGE TROPICAL CYCLONE NORTH OF GUAM, IF IT ACTUALLY DEVELOPS, WILL HAVE A SIZEABLE IMPACT ON THE EXACT TRACK OF TS 09W. IF THE NEW SYSTEM DOES DEVELOP, THEN THE TRACK WILL LIKELY PUSH THROUGH THE LUZON STRAIT. IF IT DOES NOT DEVELOP OR IS WEAKER THAN THE GFS WOULD SUGGEST, WOULD LEAD TO A TRACK FURTHER TOWARDS THE NORTH. IN TERMS OF INTENSITY, THE ENVIRONMENT CERTAINLY SUPPORTS RAPID INTENSIFICATION (RI), WITH THE EXCEPTION OF THE NORTHERLY PRESSURE AND SUBSIDENCE. THE RECENT EVOLUTION OF THE VORTEX CORE SUGGESTS IT IS STRONGER THAN EXPECTED AT THIS POINT IN THE FORECAST, SUGGESTING THAT IT MAY BE ABLE TO PUSH BACK AGAINST THE SHEAR AND SUBSINDENCE, COCOON ITSELF IN A SUPPORTIVE NEST AND UNDERGO RI. THE FORECAST THUS EXPLICITLY CALLS FOR RI TO A PEAK OF 105 KNOTS BY TAU 48. AT THIS POINT AS THE SYSTEM SLOWLY ROUNDS THE SOUTHERN PORTION OF THE TEARDROP TRACK, COOL WATER UPWELLING WILL LIMIT INTENSIFICATION THROUGH TAU 72. AFTER THIS THE SYSTEM MOVES QUICKLY INTO VERY WARM, HIGH OHC WATERS, AND WILL COMMENCE ANOTHER ROUND OF INTENSIFICATION TO A SECOND PEAK OF AT LEAST 120 KNOTS BY TAU 120. MODEL DISCUSSION: TRACK GUIDANCE IS IN FAIRLY GOOD AGREEMENT TO THE TAU 72 POINT. THEREAFTER, FAIRLY HIGH AMOUNTS OF CROSS-TRACK UNCERTAINTY BEGIN TO MANIFEST, BUT THE CROSS-TRACK SPREAD AT TAU 120 IS JUST 250NM, A MAJOR IMPROVEMENT FROM THE PREVIOUS MODEL RUN. THE JTWC FORECAST IS PLACED NEAR THE CONSENSUS MEAN AND THE GFS TRACKER THROUGH THE DURATION OF THE FORECAST. ALL AVAILABLE INTENSITY GUIDANCE SUPPORTS THE RI SCENARIO, WITH NEARLY ALL RI AIDS TRIGGERING ON THIS CYCLE. ADDITIONALY THE COAMPS-TC ENSEMBLE INTENSITY PROBABILITIES INDICATE A 60 PERCENT CHANCE OF RI THROUGH TAU 48, AND A SECONDARY HIGH PROBABILITY RI PERIOD AFTER TAU 96. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM NNNN