MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (TALIM) WARNING NR 22// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 20W (TALIM), LOCATED APPROXIMATELY 172 NM WEST OF KADENA AB HAS TRACKED NORTH-NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY INDICATES DEEP CONVECTION CONTINUING TO WRAP INTO A RAGGED, CLOUD-FILLED 32-NM EYE FEATURE. A 132151Z SSMIS 89 GHZ MICROWAVE IMAGE SHOWED DEEP, INTENSE CONVECTION COMPLETELY ENCIRCLING THE EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON DVORAK FIX LOCATIONS FROM ALL AGENCIES AS WELL AS RADAR FIX DATA FROM JMA. THE INITIAL INTENSITY IS SET AT 115 KNOTS BASED ON SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES OF T6.0 (115 KNOTS) FROM ALL REPORTING AGENCIES. TY 20W LIKELY REACHED PEAK INTENSITY AROUND 2100Z, WHEN AN INTENSITY ESTIMATE OF T6.5 (127 KNOTS) WAS REPORTED BY PGTW. TY 20W IS CONTINUING TO DRIFT SLOWLY NORTHWARD IN A HIGHLY CONDUCIVE ENVIRONMENT, WITH HIGH SEAS SURFACE TEMPERATURES AT OR ABOVE 31 DEG CELSIUS, STRONG DUAL CHANNEL OUTFLOW, AND LOW (5-10 KNOTS) VERTICAL WIND SHEAR (VWS), ENABLING ANOTHER PERIOD OF RAPID INTENSIFICATION OVER THE PAST 12 HOURS. TY TALIM REMAINS TRAPPED IN A WEAK STEERING ENVIRONMENT IN A COL AREA BETWEEN TWO SUBTROPICAL RIDGE (STR) CENTERS, ONE OVER CHINA AND THE OTHER IN THE WESTERN PACIFIC AND AN EXTENSION OF THE EASTERN STR LYING TO THE NORTH OF THE SYSTEM. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. OVER THE NEXT 24 HOURS, TY 20W WILL CONTINUE TO MEANDER GENERALLY NORTHWARD UNDER WEAK STEERING FLOW FOR THE NEXT 12 HOURS. BY TAU 24, THE NORTHERN RIDGE EXTENSION WILL WEAKEN AND MOVE EASTWARDS, ALLOWING TY 20W TO BEGIN TO ROUND THE STR AXIS AND ACCELERATE NORTHEASTWARDS. TY 20W IS EXPECTED TO MOVE NORTHEASTWARD AT ABOUT 10 KNOTS, MAKING LANDFALL ALONG THE SOUTHERN PORTION OF KYUSHU BEFORE TAU 72. THE LOW SHEAR, HIGH SSTS, AND DUAL CHANNEL OUTFLOW ENVIRONMENT WILL ALLOW THE SYSTEM TO CONTINUE TO INTENSIFY, PEAKING AT 120 KNOTS BY TAU 12. AFTER TAU 12, THE SYSTEM WILL REMAIN STEADY FOR A SHORT PERIOD AS THE HINDERED EQUATORWARD OUTFLOW IS OFFSET BY STRONGER POLEWARD OUTFLOW INTO THE DIVERGENT FLOW AHEAD OF AN APPROACHING NEGATIVELY TILTED MID-LEVEL TROUGH. AFTER TAU 36, THE SYSTEM WILL START TO WEAKEN AS VWS STARTS TO INCREASE BEYOND 40 KNOTS. DYNAMIC MODEL GUIDANCE IS IN VERY TIGHT AGREEMENT IN THE TRACK THROUGH TAU 72. C. IN THE EXTENDED FORECAST, TY TALIM WILL ACCELERATE NORTHEASTWARD AS IT BECOMES EMBEDDED IN A MID-LATITUDE TROUGH APPROACHING FROM THE WEST. AS THE SYSTEM ADVECTS LARGE AMOUNTS OF WARM AIR AT THE SURFACE, THE DOWNSTREAM RIDGE WILL BUILD, KEEPING TY 20W ON A TRACK WHICH WILL CROSS SOUTHERN HONSHU AND INTO THE SEA OF JAPAN AFTER TAU 72, THEREAFTER CONTINUING OVER HOKKAIDO AND INTO THE SOUTHERN SEA OF OKHOTSK BY TAU 120. THE SYSTEM WILL START TO BECOME EXTRA-TROPICAL BY TAU 72 AND COMPLETE EXTRA-TROPICAL TRANSITION BY TAU 120. TY 20W WILL CONTINUE TO WEAKEN AS IT CROSSES HONSHU AND THEN HOKKAIDO DUE TO TERRAIN INTERACTION COMBINED WITH HIGH VWS AND DECREASING SSTS. MODEL GUIDANCE IS IN VERY GOOD AGREEMENT ON THE TRACK BEYOND TAU 72, BUT SHOWS SOME ALONG TRACK (SPEED) DIFFERENCES DUE TO THE UNCERTAINTY ASSOCIATED WITH THE MID-LATITUDE TROUGH. WITH THE STRONG AGREEMENT IN THE OVERALL TRACK THROUGH THE ENTIRE FORECAST, THERE IS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST.// NNNN NNNN