WDPN32 PGTW 291500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 09W (SAOLA) WARNING NR 024// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 19.3N 122.7E INITIAL INTENSITY: 135 KTS GEOGRAPHIC REFERENCE: 298 NM NORTH-NORTHEAST OF MANILA, PHILIPPINES MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 46 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: SUPER TYPHOON (STY) 09W (SAOLA) HAS LITERALLY EXPLODED OVER THE PAST 12 HOURS, GOING FROM A MODERATE TYPHOON WITHOUT AN EYE, TO A 135 KNOT STY WITH A 21NM WIDE STADIUM EYE. EYE TEMPERATURES ARE NOW AN AMAZING +16C, FAR EXCEEDING THE MAGICAL WARM MEDIUM GRAY THRESHOLD IN THE IRBD IMAGERY. UNFORTUNATELY, THE PHILIPPINE RADAR NETWORK OVER NORTHEASTERN LUZON APPEARS TO BE DOWN, BUT REGARDLESS, THE LARGE STADIUM EYE IN THE ENHANCED INFRARED (EIR) IMAGERY AND A 290921Z SSMIS 91GHZ MICROWAVE IMAGE SHOW A VERY WELL-ORGANIZED SYSTEM, WITH A SINGULAR WIDE BAND OF CONVECTION COMPLETELY SURROUNDING THE EYE FEATURE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE EYE IN THE EIR AND AN EXTRAPOLATION OF THE MICROWAVE EYE. THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON AN OVERALL ASSESSMENT OF THE AGENCY CURRENT INTENSITY ESTIMATES OF T6.5 TO T7.0 AND SUBJECTIVE INTENSITY ESTIMATES BETWEEN 122-132 KNOTS. THE SYSTEM IS MOVING NORTHWEST ALONG THE SOUTHWESTERN EDGE OF A DEEP SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. CLEARLY, THE ENVIRONMENT IS CONDUCIVE TO RAPID INTENSIFICATION, WITH ZESTY SSTS WHICH HAVE RECOVERED FROM THE WEAK UPWELLING INDUCED BY TRAVERSE OF STY 09W THROUGH THIS SAME REGION FOUR DAYS AGO. OUTFLOW IS RADIAL BUT RELATIVELY CONFINED TO THE REGION AROUND THE STORM ITSELF WITH NO CLEAR OUTFLOW CHANNELS. CIMSS ANALYSIS INDICATES 21 KNOTS OF EASTERLY SHEAR, WHICH MAY IN FACT BE PRESENT, BUT ANALYSIS OF EARLIER WATER VAPOR IMAGERY SHOWS AN OUTFLOW ARC EXTENDING EASTWARD AND A SUBSIDENT AREA EAST OF THAT; A CLASSICAL SETUP FOR RI IN A MODERATE EASTERLY SHEAR ENVIRONMENT, WHICH OCCURRED IN VERY RAPID SUCCESSION TO THE ACTUAL ONSET OF THE RI. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T7.0 - 140 KTS RJTD: T6.5 - 127 KTS RCTP: T7.0 - 140 KTS KNES: T6.5 - 127 KTS CIMSS ADT: 127 KTS AT 291130Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING, OTHER THAN THE RAPID INCREASE IN THE INITIAL INTENSITY. FORECAST DISCUSSION: STY 09W HAS EXCEEDED ALL EXPECTATIONS, AND UNDERGONE EXTREME RAPID INTENSIFICATION, EXPLODING FROM NEAR 100 KNOTS AT 290000Z TO 135 KNOTS 12 HOURS LATER. AS THE SYSTEM TRAVERSES THE NORTHERN BABUYAN ISLANDS OVER THE NEXT 12 HOURS, IT IS LIKELY TO INTENSIFY ANOTHER FEW KNOTS, WITH THE FORECAST PEAKING OUT AT 140 KNOTS BY TAU 12. THE SYSTEM WILL THEN CONTINUE TRACKING WEST-NORTHWEST INTO THE NORTHERN PORTION OF THE SOUTH CHINA SEA (SCS) THROUGH TAU 48, PASSING WELL SOUTH OF TAIWAN ON ITS WAY TOWARDS THE CHINESE COAST UNDER THE STEERING INFLUENCE OF THE STR CENTERED FAR TO THE NORTHEAST. AROUND TAU 48, A RELATIVELY DEEP MID-LATITUDE TROUGH WILL PASS BY TO THE NORTH, BUT WILL REMAIN FAR ENOUGH TO THE NORTH TO NOT INFLUENCE THE TRACK OF STY 09W ALL THAT MUCH. THE TRANSIENT ANTICYCLONE THAT DEVELOPS IN THE WAKE OF THIS TROUGH, HOWEVER WILL HAVE AN IMPACT, TURNING THE SYSTEM ONTO A MORE WESTWARD TRACK BY AFTER TAU 48. THE TRANSIENT ANTICYCLONE QUICKLY MOVES NORTHEAST AND IS ABSORBED INTO THE LARGER STR COMPLEX, BUT LEAVES BEHIND A SHARP RIDGE WHICH EXTENDS ALL THE WAY FROM SOUTHERN CHINA TO 40N 160E. THIS RIDGE PATTERN WILL SERVE TO PUSH STY 09W ONTO A WEST-SOUTHWEST TRACK FROM TAU 72 ONWARD, WITH THE TRACK SKIRTING THE COAST NEAR HONG KONG BY TAU 96 THEN OPENING THE DISTANCE TO THE COAST THEREAFTER. IN TERMS OF INTENSITY, AS MENTIONED, THE SYSTEM IS FORECAST TO PEAK AT 140 KNOTS WITHIN THE NEXT 12 HOURS. THE CIMSS M-PERC EYEWALL REPLACEMENT CYCLE (EWRC) MODELS ARE STARTING TO RAMP UP AGAIN, WITH THE FULL-MODEL PREDICTING A 30 PERCENT PROBABILITY OF EWRC WHILE THE VMAX-MODEL SHOWING 60 PERCENT. WITH SUCH AN INTENSE SYSTEM UNDER THE INFLUENCE OF MODERATE EASTERLY SHEAR, THE ONSET OF AN EWRC IS LIKELY WITHIN THE NEXT 24 HOURS. HENCE THE SYSTEM IS FORECAST TO WEAKEN AS IT TRACK SOUTHWEST OF TAIWAN, BUT THEN MAINTAIN INTENSITY AS IT TAPS INTO A MODEST POLEWARD OUTFLOW CHANNEL AROUND TAU 48 WHICH SHOULD HELP THE SYSTEM TO RECOVER FROM A POSSIBLE EWRC. BY TAU 72, THE SYSTEM BEGINS TO FEEL THE EFFECTS TO COOLER WATERS, INGESTION OF DRY CONTINENTAL AIR FROM MAINLAND CHINA AND AN INCREASE IN MID-LEVEL SHEAR, MARKING THE BEGINNING OF A STEADY WEAKENING TREND THAT CONTINUES THROUGH THE END OF THE FORECAST PERIOD. MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE HAS COME INTO SLIGHTLY BETTER AGREEMENT WITH THE LATEST RUN. THE ECMWF CONTINUES TO TRACK THE SYSTEM INTO CHINA IN THE VICINITY OF SHANTAU, WHILE THE GFS CONTINUES TO TAKE A MORE SOUTHERN ROUTE. HOWEVER, THE ECMWF IS NOW THE SOLE OUTLIER ON THE NORTHERN SIDE OF THE ENVELOPE WHILE THE MAJORITY OF THE OTHER CONSENSUS MEMBERS HAVE NOW JOINED THE GFS SIDE, PULLING THE SYSTEM FURTHER SOUTHWARD. THE CONSENSUS AND THE JTWC FORECAST STILL LIE ON THE NORTHERN EDGE OF THE TIGHTEST MODEL PACKING IN THE ENVELOPE. IN THE EXTENDED FORECAST, THE GFS, NAVGEM AND GFS ENSEMBLE AS WELL AS THE CONSENSUS MEAN SHOW THE SYSTEM BECOMING QUASI-STATIONARY OR TURNING SLOWLY BACK TOWARDS THE EAST, LIKELY IN RESPONSE TO A FURTHER WESTWARD TRACK OF TS 10W IN THE PHILIPPINE SEA. WHILE CONSIDERED UNLIKELY AT THIS TIME, THIS SCENARIO WILL BEAR CLOSE SCRUTINY IN LATER MODEL RUNS. INTENSITY GUIDANCE IS MIXED AND STRUGGLING TO CATCH UP TO THE ERI, HOWEVER THE HAFS-A AND COAMPS-TC SUPPORT A GENERALLY FLAT INTENSITY TREND THROUGH TAU 48 FOLLOWED BY RAPID WEAKENING AS THE SYSTEM APPROACHES HONG KONG. THE JTWC FORECAST LIES CLOSE TO THE HAFS-A GUIDANCE THROUGH THE BULK OF THE FORECAST PERIOD. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN