WDPN31 PGTW 221500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (SURIGAE) WARNING NR 037// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 02W (SURIGAE), LOCATED APPROXIMATELY 355 NM SOUTH- SOUTHWEST OF KADENA AB, HAS TRACKED NORTHEASTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON RECENT SATELLITE FIXES FROM PGTW, KNES AND RJTD AND A LOW-LEVEL CENTER FEATURE EVIDENT IN 221010Z SSMIS 37 GHZ MICROWAVE IMAGERY. THE INITIAL INTENSITY OF 85 KNOTS IS CONSISTENT WITH A CONSENSUS OF SUBJECTIVE DVORAK T-NUMBER ESTIMATES (RANGING FROM 77 TO 102 KNOTS) FROM THE SAME REPORTING AGENCIES. TY 02W CONTINUES TO ROUND THE AXIS OF A SUBTROPICAL STEERING RIDGE SITUATED TO THE SOUTHEAST OF THE SYSTEM. DEEP CONVECTION HAS BECOME INCREASINGLY FRAGMENTED, CLOUD TOPS HAVE WARMED SIGNIFICANTLY WITHIN THE EASTERN PORTION OF THE CIRCULATION AND A CLEAR EYE IS NO LONGER EVIDENT IN INFRARED SATELLITE IMAGERY. ENVIRONMENTAL ANALYSIS INDICATES MODERATE AND INCREASING VERTICAL WIND SHEAR (ABOUT 20 KNOTS), MARGINAL SEA SURFACE TEMPERATURES (26-27 CELSIUS) AND PERSISTENT, FAVORABLY STRONG EASTWARD AND POLEWARD OUTFLOW ALOFT. 3. FORECAST REASONING. A. EXTRATROPICAL TRANSITION IS NOW EXPECTED TO BE COMPLETE BY TAU 96. OTHERWISE, THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 02W WILL CONTINUE TO TURN EASTWARD AND DIP SLIGHTLY EQUATORWARD AS IT ROUNDS THE SUBTROPICAL STEERING RIDGE AXIS OVER THE NEXT 36 TO 48 HOURS. STEADY WEAKENING IS EXPECTED AS WESTERLY VERTICAL WIND SHEAR INCREASES AND ALONG TRACK SEA SURFACE TEMPERATURES DECREASE. BY TAU 72, AN AMPLIFYING MID-LATITUDE TROUGH WILL BEGIN TO INTERACT WITH TY 02W AND, FOR THE REST OF THE FORECAST PERIOD, THE SYSTEM WILL BECOME EMBEDDED WITHIN THE FLOW ASSOCIATED WITH THIS TROUGH. STRONG VERTICAL WIND SHEAR AND PASSAGE OVER COOLER WATER WILL LEAD TO STEADY WEAKENING IN THE MEDIUM TERM. HOWEVER, BAROCLINIC SUPPORT AHEAD OF THE AFOREMENTIONED MID-LATITUDE TROUGH IS EXPECTED TO SUSTAIN THE SYSTEM NEAR STORM FORCE (50 KNOTS) AS THE SYSTEM UNDERGOES EXTRATROPICAL TRANSITION. NUMERICAL MODEL GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH TAU 72, LENDING HIGH CONFIDENCE TO THE INITIAL PORTION OF THE OFFICIAL TRACK FORECAST. C. IN THE EXTENDED PERIOD, TY 02S IS EXPECTED TO ACCELERATE NORTHEASTWARD AND COMPLETE EXTRATROPICAL TRANSITION AS A STRONG LOW PRESSURE SYSTEM AS IT MERGES WITH A MID-LATITUDE TROUGH. TRACK GUIDANCE DIVERGES IN THE EXTENDED RANGE AS THE GFS AND GEFS ENSEMBLE MEAN DEPICT A WEAKENED SYSTEM REMAINING SEPARATE FROM THE MID- LATITUDE WESTERLY FLOW PATTERN, WHILE MOST OTHER AVAILABLE DETERMINISTIC MODEL GUIDANCE DEPICTS ACCELERATION INTO THE MID- LATITUDE WESTERLIES. THE GEFS, EC-EPS, GALWEM-GE, ACCESS-GE AND COAMPS-TC ENSEMBLES PRESENT A MIXED PICTURE, WITH MANY MEMBERS DEPICTING ACCELERATION INTO THE MID-LATITUDE WESTERLIES AND A LARGE SHARE INDICATING A WEAKENED, MEANDERING SYSTEM CONSISTENT WITH THE GFS SOLUTION. THE CURRENT FORECAST FAVORS ACCELERATION INTO THE MID- LATITUDE FLOW, CONSISTENT WITH THE MULTI-MODEL CONSENSUS AND PREVIOUS FORECASTS, BUT THE NON-ACCELERATION OUTCOME IS A NOTEWORTHY ALTERNATE SCENARIO. GIVEN THESE UNCERTAINTIES, CONFIDENCE IN THE EXTENDED RANGE JTWC TRACK FORECAST IS LOW.// NNNN