WDPN31 PGTW 030300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (HINNAMNOR) WARNING NR 024// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 23.1N 124.7E INITIAL INTENSITY: 80 KTS GEOGRAPHIC REFERENCE: 265 NM SOUTHWEST OF KADENA AB MOVEMENT PAST 6 HOURS: NORTHWARD AT 07 KTS SIGNIFICANT WAVE HEIGHT: 40 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT WHILE TY 12W IS SLOWLY INTENSIFYING AND ATTEMPTING TO CLEAR OUT AN EYE, IT HAS YET TO PUT THE PEDAL DOWN. CONVECTIVE HOT TOWERS HAVE BEEN DEVELOPING AND ROTATING AROUND THE CENTER CONSISTENTLY OVER THE PAST SIX HOURS BUT HAVE YET TO DEVELOP OR SUSTAIN A CONSISTENT EYEWALL. PART OF THE ISSUE LIES IN THE WEDGE OF VERY DRY AIR BETWEEN 450-300MB AND 50-55 KNOT WINDS SEEN IN THE ISHIKAGIJIMA 1200Z SOUNDING, WHICH IS INHIBITING DEVELOPMENT ON THE NORTHERN EDGE OF THE SYSTEM, BORNE OUT BY THE STRUGGLING STRUCTURE ON THAT SIDE OF THE SYSTEM. A 022230Z SSMIS 91GHZ MICROWAVE IMAGE REVEALED AN ASYMMETRIC CONVECTIVE STRUCTURE, WITH THE BULK OF DEEP CONVECTION LIMITED TO THE SOUTHERN SECTORS WITH WEAKER CONVECTION AROUND THE NORTHERN PORTION OF THE CORE. A 022136Z SENTINEL-1A SAR PASS REVEALED THAT IN THE LOW LEVELS, THE STRUCTURE IS MUCH BETTER, WITH A 25-NM EYE WITH A SMALL CORE OF ENHANCED STORM FORCE WINDS. HOWEVER THE CORE IS EXTREMELY SMALL AND THE WIND FIELD HIGHLY ASYMMETRIC WITH HURRICANE FORCE WINDS LIMITED TO THE EASTERN SECTORS, ABOUT 50 TO 75 NM OUT. THE SAR PASS IN CONJUNCTION WITH A RADAR EYE FEATURE LENT HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY OF 80 KNOTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE SAR FIX OF 76 KNOTS, THE BULK OF AGENCY FIXES, THE AIDT OF 78 KNOTS, AS WELL AS SOME NEW DEVELOPMENTAL CIMSS PRODUCTS INCLUDING DEEP MULTINET (79 KTS) AND THE OPEN-AIIR (75 KTS). THE SYSTEM IS WOBBLING NORTHWARD AT A MODEST PACE, ALONG THE WESTERN SIDE OF A DEEP SUBTROPICAL RIDGE (STR) TO THE EAST. INITIAL WIND RADII BASIS: SAR DATA CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE (STR) TO THE EAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T5.0 - 90 KTS KNES: T4.5 - 77 KTS CIMSS SATCON: 68 KTS AT 022231Z CIMSS ADT: 84 KTS AT 022340Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 30-31 CELSIUS OUTFLOW: STRONG RADIAL OTHER FACTORS: MID-LEVEL SHEAR AND DRY AIR TO THE NORTH. ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY 12W HAS DEFINITELY STARTED ITS NORTHWARD MOVEMENT OVER THE PAST SIX HOURS, THOUGH IT IS STILL WOBBLING A BIT EITHER SIDE OF DUE NORTH. TRACK SPEED IS STARTING TO PICK UP, NOW UP TO ABOUT SEVEN KNOTS AS THE STEERING RIDGE TO THE EAST STRENGTHENS. TY 12W IS FORECAST TO CONTINUE TRACKING JUST A SHADE WEST OF DUE NORTH OVER THE NEXT 36 HOURS, PASSING JUST EAST OF ISHIKAGIJIMA IN THE NEXT 12 HOURS, THEN ENTERING THE EAST CHINA SEA. THE STEERING RIDGE WILL BEGIN TO REORIENT AROUND TAU 36, ALLOWING TY 12W TO TAKE A FAIRLY SHARP NORTHEASTWARD TURN BY TAU 48. SHORTLY AFTER THIS POINT, IT WILL SLAM THE FOOT ON THE GAS AND ACCELERATE TO THE NORTHEAST ALONG THE STRONG GRADIENT BETWEEN THE RIDGE TO THE EAST AND A STRONG MID-LATITUDE TROUGH APPROACHING FROM THE WEST, PASS OVER THE SOUTHERN COAST OF KOREA AND THEN EXIT INTO THE SEA OF JAPAN, MOVING AT OVER 25 KNOTS BY THIS POINT. IN TERMS OF INTENSITY, WHILE BULK SHEAR IS LOW, THIS DOES NOT TELL THE WHOLE STORY. THE SYSTEM IS SLOWLY INTENSIFYING BUT IS FACING SOME RESISTANCE FROM MID-LEVEL SHEAR AND UPPER-LEVEL DRY AIR TO THE NORTH AS MENTIONED ABOVE. AN ADDITIONAL INHIBITING FACTOR IS SOME PRESSURE FROM NORTHERLY, CONVERGENT FLOW TO THE WEST, WHICH IS BLOCKING OUTFLOW IN THAT DIRECTION. GLOBAL MODEL ANALYSIS INDICATES THE WEDGE OF DRY AIR TO THE NORTH, AS WELL AS THE MID-LEVEL SHEAR SHOULD DECREASE OVER THE NEXT 12 HOURS, WHILE THE NORTH-NORTHEASTERLY FLOW OFF TO THE WEST SHOULD RECEDE AWAY FROM THE SYSTEM, ALLOWING FOR INCREASED RADIAL OUTFLOW. ADDITIONALLY AS THE SYSTEM MOVES FURTHER NORTH AWAY FROM THE UPWELLING INDUCED COOL POOL, SSTS WILL INCREASE TO OVER 30C, PROVIDING AMPLE ENERGY FOR INTENSIFICATION. THE PEAK INTENSITY IS INCREASED TO 115 KNOTS BY TAU 48 BUT IT IS POSSIBLE THAT THE PEAK MAY BE SLIGHTLY HIGHER AND OCCUR SLIGHTLY LATER, AS THE SYSTEM HAS A BRIEF WINDOW, TO ABOUT TAU 60, TO TAP INTO SOME GOOD POLEWARD OUTFLOW PRIOR TO THE ONSET OF HIGH SHEAR. REGARDLESS, BY TAU 72 SHEAR WILL INCREASE DRAMATICALLY, THE SYSTEM WILL MOVE OVER COOLER WATERS LESS THAN 27C AND WILL BEGIN TO INTERACT WITH THE TERRAIN OF SOUTHERN KOREA, AND WEAKEN TO 90 KNOTS. AS IT CROSSES THE COAST OF KOREA, TY 12W WILL BEGIN TO INTERACT WITH THE MID-LATITUDE WESTERLY FLOW ALOFT AND BEGIN EXTRA-TROPICAL TRANSITION. THE SYSTEM WILL COMPLETE TRANSITION TO A WARM SECLUSION TYPE EXTRA-TROPICAL SYSTEM NO LATER THAN TAU 96 IN THE SEA OF JAPAN. MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE REMAINS VERY CONSISTENT RUN TO RUN AND WITH VERY LITTLE SPREAD, PARTICULARLY THROUGH TAU 48. CROSS-TRACK SPREAD REMAINS LOW THROUGH TAU 96, BUT ALONG TRACK SPREAD INCREASES TO 600NM BETWEEN THE SLOW NAVGEM AND FAST JGSM MODELS, WHICH IS NOT ALL THAT UNUSUAL IN AN ETT SCENARIO. THE JTWC FORECAST REMAINS CONSISTENT WITH THE PREVIOUS FORECAST WITH HIGH CONFIDENCE THROUGH TAU 72, AND MEDIUM CONFIDENCE THEREAFTER. INTENSITY GUIDANCE IS SOMEWHAT MIXED, WITH THE DECAY-SHIPS CONTINUING TO HAVE LITTLE FAITH IN HINNAMNORS POTENTIAL, SHOWING NO FURTHER INTENSIFICATION THROUGH THE FORECAST PERIOD. MEANWHILE, GFS, HWRF AND THE CONSENSUS PEAK THE SYSTEM AT AROUND 90 KNOTS, WHILE THE COAMPS-TC, AND ENSEMBLE INTENSIFY THE SYSTEM TO AROUND 115 KNOTS. ADDITIONALLY, THE RAPID INTENSIFICATION PREDICTION AID (RIPA) HAS TRIGGERED ON THIS RUN, INDICATING A 40 PERCENT OR HIGHER PROBABILITY OF RI. THE JTWC FORECAST LIES ALONG A SHALLOWER SLOPE THAN THE RIPA, BUT ABOVE THE BULK OF THE GUIDANCE. HOWEVER, WITH SUCH A LARGE SPREAD IN THE GUIDANCE, THERE IS MEDIUM TO LOW CONFIDENCE IN THE FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN