WDPN31 PGTW 310900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (IN-FA) WARNING NR 032// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 22.2N 142.9E INITIAL INTENSITY: 115 KTS GEOGRAPHIC REFERENCE: 179 NM SOUTH-SOUTHEAST OF IWO TO MOVEMENT PAST 6 HOURS: NORTHWARD AT 08 KTS SIGNIFICANT WAVE HEIGHT: 50 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON (TY) 30W MAINTAINING A WELL-DEFINED EYE FEATURE, WHICH HAS CONSTRUCTED SLIGHTLY OVER THE PAST SIX HOURS TO 37 NM. MULTIPLE MESOVORTICES ARE CLEARLY VISIBLE ROTATING ALONG THE INNER EYEWALL, GENERATING A WAVENUMBER-3 ASYMMETRY. OVER THE PAST SIX HOURS, THE PRIMARY EYEWALL HAS BEGUN TO DEGRADE AND BECOME MORE ASYMMETRIC, THOUGH INNER-EYE TEMPERATURES REMAIN NEAR 19C. A 310300Z AMSR3 COLOR-ENHANCED 89 GHZ MICROWAVE IMAGE DEPICTS A SYMMETRICAL INNER EYEWALL, ROUGHLY 10 NM WIDE, SEPARATED BY A THIN (APPROXIMATELY 10 NM WIDE) MOAT FEATURE FROM A ROBUST, 40 NM WIDE SECONDARY EYEWALL. THE CIMSS M-PERC HOVMOLLER DIAGRAM CLEARLY INDICATES THAT SECONDARY EYEWALL FORMATION (SEF) BEGAN AROUND 301800Z, AND THE SECONDARY EYEWALL HAS SINCE BEEN GRADUALLY CONTRACTING IN SIZE WHILE THE INNER EYEWALL SLOWLY DEGRADES. AT THE SYNOPTIC SCALE, A WEAK FRONTAL BOUNDARY IS LOCATED APPROXIMATELY 400 NM NORTHWEST OF TY 30W, MOVING SOUTHEASTWARD. IN THE UPPER-LEVELS, ANIMATED WATER VAPOR IMAGERY DEPICTS A MESOSCALE POINT-SOURCE OUTFLOW PATTERN DIRECTLY OVERLYING 30W, AND DUAL UPPER- TROPOSPHERIC ANTICYCLONES AT 200 MB BOTH EAST AND WEST OF THE SYSTEM, PROVIDING STRONG RADIAL OUTFLOW ENHANCED BY A ROBUST POLEWARD OUTFLOW CHANNEL. THE INITIAL MOTION VECTOR IN THE ANALYSIS IS NORTH AT 08 KNOTS; HOWEVER, THIS SMOOTHS OUT A TEMPORARY NORTHEASTWARD TRAJECTORY OBSERVED FROM ABOUT 0300Z TO 0600Z BASED ON THE ANIMATED MSI. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE WELL- DEFINED EYE IN THE MSI. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, BASED ON A BLEND OF THE OBJECTIVE AND SUBJECTIVE INTENSITY ESTIMATES OUTLINED BELOW. ENVIRONMENTAL CONDITIONS ARE FAVORABLE OVERALL, BUT REMAIN TEMPERED BY THE ONGOING EYEWALL REPLACEMENT CYCLE (ERC) AND THERMODYNAMIC LIMITATIONS FROM SELF- INDUCED OCEANIC UPWELLING AS THE SYSTEM DECELERATES AND BECOMES QUASI-STATIONARY. INITIAL WIND RADII BASIS: EYEWALL REPLACEMENT CYCLE (ERC) AND OCEANIC UPWELLING. CURRENT STEERING MECHANISM: WEAK STEERING PATTERN INFLUENCED BY A BIFURCATED SUBTROPICAL RIDGE (STR) TO THE EAST AND TO THE WEST NEAR TAIWAN, AND A SHALLOW MID-LATITUDE TROUGH TO THE NORTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T6.0 - 115 KTS RJTD: T6.0 - 115 KTS RCTP: T5.5 - 102 KTS CIMSS SATCON: 108 KTS AT 310500Z CIMSS ADT: 112 KTS AT 310530Z CIMSS AIDT: 110 KTS AT 310530Z CIMSS D-PRINT: 117 KTS AT 310600Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 0-5 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TYPHOON (TY) 30W HAS BEGUN TURNING POLEWARD IN REACTION TO THE IMMINENT PASSAGE OF A MODERATELY DEEP MID-LATITUDE TROUGH TO THE NORTH, WHICH IS ERODING THE WESTERN FLANK OF THE EASTERN STR. WHILE THE TROUGH IS STRONG ENOUGH TO WEAKEN THE RIDGE, GLOBAL DYNAMICAL MODELS SUGGEST THAT IT LACKS THE AMPLITUDE AND DYNAMICS NECESSARY TO FACILITATE EXTRA-TROPICAL TRANSITION OR PULL TY 30W POLEWARD INTO THE MID-LATITUDE WESTERLIES AT THIS TIME. THUS, TY 30W REMAINS TRAPPED IN A COL BETWEEN COMPETING RIDGES TO THE EAST AND WEST, AND THE TROUGH TO T…