WDPN32 PGTW 210900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (SURIGAE) WARNING NR 032// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 02W (SURIGAE), LOCATED APPROXIMATELY 307 NM NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTH-NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES THAT SURIGAE HAS MAINTAINED A VERY LARGE 60NM EYE, WITH A SMALLER REMNANT INNER EYE OF ABOUT 40 NM DIAMETER. THE INNER CORE REMAINS WELL ORGANIZED AND SYMMETRIC, BUT CLOUD TOP TEMPERATURES HAVE WARMED SIGNIFICANTLY OVER THE PREVIOUS SIX HOURS. ANIMATED ENHANCED INFRARED IMAGERY REVEALS SOME EROSION OF THE CONVECTIVE STRUCTURE ON THE WESTERN SIDE, INDICATIVE OF THE ENTRAINMENT OF SOME MID-LEVEL DRIER AIR RESIDENT OVER LUZON. THE INITIAL POSITION IS SET WITH HIGH CONFIDENCE BASED ON THE WELL DEFINED EYE IN THE MSI AND NEAR THE TIGHT GROUPING OF MULTI-AGENCY FIX POSITIONS. THE INITIAL INTENSITY IS LOWERED TO 115 KNOTS, IN LINE WITH DVORAK CURRENT INTENSITY ESTIMATES OF T5.5 TO T6.0, AN ADT ESTIMATE OF T5.9 AND A SATCON ESTIMATE OF 110 KTS. THE SYSTEM IS TRACKING SLOWLY NORTH-NORTHWESTWARD ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE EAST. THE OVERALL ENVIRONMENT REMAINS FAVORABLE WITH LOW (8-10 KTS) VWS, STRONG POLEWARD OUTFLOW AND SUPPORTIVE (~27C) SSTS. THE SYSTEM IS MOVING OVER PROGRESSIVELY COOLER WATERS, WHICH WILL BE THE PRIMARY FACTOR ARRESTING ANY FURTHER INTENSIFICATION IN THE NEAR TERM. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. OVER THE NEXT 12 HOURS, TY SURIGAE WILL SLOWLY MOVE OVER TO A MORE NORTHWARD TRACK AS IT APPROACHES THE AXIS OF THE STR. BY TAU 24, IT WILL HAVE ROUNDED THE STR AXIS AND BEGIN ACCELERATING EAST- NORTHEASTWARD ALONG THE NORTHWEST PERIPHERY OF THE STR TO SOUTHEAST. THE STR WEAKENS AND MOVES SOUTH BY TAU 48, AND SURIGAE WILL TRANSITION TO AN EASTWARD TRACK THROUGH TAU 72. OVER THE NEXT 24 HOURS AS THE SYSTEM ROUNDS THE RIDGE, SLOW WEAKENING IS EXPECTED, PRIMARILY DUE TO LOWER SSTS AND THE INFLUENCE OF MID-LEVEL DRIER AIR. THE ENVIRONMENT BECOMES INCREASINGLY HOSTILE AFTER TAU 36 AS A SHORTWAVE TROUGH CURRENTLY OVER EASTERN CHINA RAPIDLY APPROACHES TY SURIGAE, BRINGING DRAMATICALLY INCREASED MID-LEVEL SHEAR AND CONVERGENT FLOW ALOFT. STEADY AND MORE RAPID WEAKENING IS FORECAST AFTER TAU 36 AS THE SYSTEM COMES UNDER THE INCREASED SHEAR BROUGHT ON BY INTERACTION WITH THE TROUGH. BY TAU 72 THE TROUGH IS EXPECTED TO HAVE MOVED PAST SURIGAE, LEAVING A SIGNIFICANTLY WEAKENED SYSTEM LINGERING IN ITS WAKE BUT STILL MOVING EASTWARD. DYNAMIC MODEL SOLUTIONS ARE IN GOOD AGREEMENT THOUGH TAU 48, BUT DIVERGE AT THIS POINT, WITH VARYING DEGREES OF INTERACTION WITH THE SHORTWAVE AND SURIGAE. THE GFS, THE GFS ENSEMBLE AND THE HWRF SOLUTIONS DEPICT MINIMAL INTERACTION WITH THE TROUGH AND DRIVE SURIGAE SLOWLY SOUTHEASTWARD AFTER TAU 48. THE UKMET, UKMET ENSEMBLE, ECMWF, AND NAVGEM HOWEVER DEPICT SIGNIFICANTLY MORE INFLUENCE WITH BETWEEN THE TROUGH AND SURIGAE, AND MOVE THE SYSTEM MORE RAPIDLY TO THE EAST- NORTHEAST AFTER TAU 48. THE CURRENT FORECAST TRACK THROUGH TAU 72 MORE CLOSELY FAVORS THE EUROPEAN MODEL CONSENSUS WITH MODERATE CONFIDENCE, AS THE MAJORITY OF THE DIVERGENCE IN SOLUTIONS OCCURS BEYOND AT AND BEYOND TAU 72. C. BEYOND TAU 72, THE FORECAST BECOMES INCREASINGLY UNCERTAIN, WITH THE INTERACTION WITH A SECOND MAJOR SHORTWAVE TROUGH DIVING SOUTHWARD FROM THE KOREAN PENINSULA BEING THE MAJOR FACTOR IN THE FORECAST. MODEL GUIDANCE DEPICTS A WIDE RANGE OF POTENTIAL SOLUTIONS BASED ON THE VARIANCE IN RELATIVE POSITIONING BETWEEN THE TROUGH AND SURIGAE. THE GFS AND GFS ENSEMBLE CONTINUE TO SHOW LIMITED TO NO INTERACTION WITH THE TROUGH AND HOLD SURIGAE TO THE SOUTH NEAR 20N THROUGH TAU 120, AS A SUBTROPICAL SYSTEM. THE REMAINDER OF THE MODEL GUIDANCE DEPICT A MUCH STRONGER TROUGH DIPPING FURTHER SOUTH, WITH SURIGAE BECOMING EMBEDDED WITHIN THE ASSOCIATED BAROCLINIC ZONE AND RACING OFF TO THE NORTHEAST AS AN EXTRA-TROPICAL CYCLONE. THE CURRENT FORECAST GENERALLY FAVORS THE GROUP OF CONSENSUS MEMBERS DEPICTING THE NORTHEAST TRACK AND EXTRA-TROPICAL TRANSITION (ETT), THOUGH THE TRACK REMAINS SLOWER AND FURTHER SOUTH THAN THE CONSENSUS MEAN. SURIGAE IS FORECAST TO STEADILY WEAKEN THROUGH TAU 120 AS HIGH SHEAR AND MARGINAL SSTS OFFSET THE ROBUST OUTFLOW INTO THE MID- LATITUDE WESTERLIES. THE TRACK AND INTENSITY FORECAST REMAINS HIGHLY DEPENDENT ON THE DETAILS OF THE SECOND TROUGH AND ITS INTERACTION WITH SURIGAE AND THUS BOTH TRACK AND INTENSITY FORECASTS BEYOND TAU 72 ARE HIGHLY UNCERTAIN.// NNNN