MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 20W (HAGIBIS) WARNING NR 009// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUPER TYPHOON (STY) 20W (HAGIBIS), LOCATED APPROXIMATELY 220 NM EAST-NORTHEAST OF ANDERSEN AFB, GUAM, HAS TRACKED WEST-NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. TY 20W IS UNDERGOING EXTREME RAPID INTENSIFICATION (ERI: 55KTS IN 24HRS) FROM 50KTS AT 060600Z TO THE CURRENT INTENSITY OF 130 KNOTS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A COMPACT AND SHARPLY-OUTLINED EYEWALL WITH A PINHOLE 5NM EYE. THE MSI LOOP ALSO SHOWS THE SPIRAL RAIN BANDS ARE WRAPPING VERY TIGHTLY TOWARD THE EYEWALL RESULTING IN A SUPER-CONDENSE AND SYMMETRIC SYSTEM. UPPER-LEVEL ANALYSIS INDICATES RADIAL OUTFLOW (PLUS VERY STRONG EQUATORWARD AND EASTWARD BIASES) WITH LOW VERTICAL WIND SHEAR (VWS). SST VALUES OF 29-30C AND HIGH OCEAN HEAT CONTENT VALUES ALSO SUPPORT THE ERI. THE CURRENT INTENSITY IS HELD ON THE HIGH END OF AGENCY DVORAK ESTIMATES RANGING FROM T5.5/102KTS TO T7.0/140KTS. THE SYSTEM IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. STY 20W CONTINUES TO UNDERGO ERI, THEREFORE, THE FORECAST INTENSITIES HAVE AGAIN BEEN ADJUSTED SIGNIFICANTLY HIGHER THAN THE PREVIOUS FORECAST. THE TRACK FORECAST, HOWEVER, REMAINS CONSISTENT. B. STY 20W IS FORECAST TO TRACK NORTHWESTWARD THROUGH TAU 72 UNDER THE STEERING INFLUENCE OF THE STR. THE HIGHLY FAVORABLE ENVIRONMENTAL CONDITIONS ARE EXPECTED TO PERSIST AND PROMOTE FURTHER RI TO A PEAK OF 150KTS (POSSIBLY HIGHER) AROUND TAU 24 WHEN THE POLEWARD OUTFLOW IS FURTHER ENHANCED BY INITIAL EXPOSURE TO THE PREVAILING WESTERLIES AHEAD OF A SHORTWAVE TROUGH DIGGING INTO JAPAN. AFTERWARD, INCREASING VWS WILL TEMPER THE INTENSITY DOWN TO 135KTS BY TAU 72, ALBEIT STILL A STY. NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH A GRADUAL SPREAD TO 230NM BY TAU 72, LENDING HIGH CONFIDENCE IN THIS PORTION OF THE JTWC TRACK FORECAST. C. IN THE EXTENDED PERIOD, STY HAGIBIS WILL TURN MORE NORTHWARD AS IT CRESTS THE STR AXIS TOWARD A BREAK IN THE STR ASSOCIATED WITH THE SHORTWAVE TROUGH FORECAST TO DEEPEN OVER JAPAN. INCREASING VWS WILL OFFSET THE OTHERWISE FAVORABLE ENVIRONMENT AND GRADUALLY ERODE THE SYSTEM DOWN TO 105KTS BY TAU 120 - STILL A VERY STRONG TYPHOON - AS IT APPROACHES SOUTHERN JAPAN. NUMERICAL MODELS DIVERGE SIGNIFICANTLY TO OVER 600NM AT TAU 120, LENDING LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.// NNNN NNNN