WDPN31 PGTW 230300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 34W (MAN-YI) WARNING NR 14// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 34W (MAN-YI), LOCATED APPROXIMATELY 675 NM SOUTH- SOUTHWEST OF IWO TO, HAS TRACKED NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A ROBUST CENTRAL DENSE OVERCAST AND CONVECTIVE BANDS WRAPPING INTO THE LOW LEVEL CIRCULATION CENTER (LLCC). A 222208Z SSMIS 91GHZ IMAGE REVEALS THE MAJORITY OF DEEP CONVECTION ON THE WESTERN SIDE OF THE STORM, PRESSURED BY EASTERLY VERTICAL WIND SHEAR. THE AFOREMENTIONED MICROWAVE IMAGE ALSO FEATURES A MICROWAVE EYE, UPON WHICH THE INITIAL POSITION IS BASED WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 90 KNOTS, IN AGREEMENT WITH THE DVORAK CURRENT INTENSITY ESTIMATE FROM PGTW OF T5.0 (90 KTS), AND ABOVE THE KNES ESTIMATE OF T4.5 (77 KTS). STRONG DIVERGENCE ALOFT AND WARM (26-28 DEGREES CELSIUS) SEA SURFACE TEMPERATURES (SSTS) ARE FUELING THE PERSISTENT CONVECTION, AND VERTICAL WIND SHEAR (VWS) HAS EASED SLIGHTLY TO BECOME LOW TO MODERATE (15 TO 20 KTS), ALLOWING FOR SLIGHT INTENSIFICATION OVER THE PAST 6 HOURS. TY 34W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. WIND RADII WERE ADJUSTED BASED ON A 222354Z ASCAT IMAGE. B. TY 34W IS FORECAST TO TRACK NORTH-NORTHWESTWARD TO NORTHWARD THROUGH TAU 48 AS IT TRACKS ALONG THE WESTERN PERIPHERY OF THE DEEP-LAYERED STR POSITIONED TO THE EAST. A STRONG, BROAD HIGH PRESSURE SYSTEM WILL BUILD INTO JAPAN AFTER TAU 24. LOW-LEVEL NORTHEASTERLY FLOW ASSOCIATED WITH THIS HIGH IS FORECAST TO SLOW THE SYSTEM'S FORWARD MOTION AND TURN THE SYSTEM NORTHWESTWARD TO WESTWARD BY TAU 36. HOWEVER, WEAKENING UPPER AIR DIVERGENCE, ALONG WITH COLD AIR ADVECTION AND SUSTAINED HIGH VWS, WILL BEGIN TO WEAKEN TY 34W AFTER TAU 12. THE MOST RECENT MULTI-MODEL CONSENSUS AND JTWC FORECAST TRACK HAVE SHIFTED SLIGHTLY TO THE EAST, PORTRAYING A MORE PRONOUNCED SLOWDOWN AND DRAMATIC TURN TO THE WEST AROUND TAU 36. ECMWF IS THE EASTERN OUTLIER, WHILE THE JAPANESE MODELS ARE THE WESTERN OUTLIERS AND SHOW A MORE GRADUAL WESTWARD TURN. C. AFTER TAU 72, NUMERICAL MODEL GUIDANCE CONTINUES TO DIVERGE WITH A 922NM SPREAD IN SOLUTIONS AT TAU 120. THE BULK OF THE MODELS INDICATE RAPID WEAKENING EXCEPT NAVGEM, WHICH MAINTAINS TYPHOON STRENGTH THROUGH TAU 120. THE JTWC TRACK AND INTENSITY FORECAST FAVORS A RAPID WEAKENING AND EVENTUAL DISSIPATION SCENARIO ASSOCIATED WITH THE NORTHEASTERLY SURGE, WHICH WILL ADVECT COOLER, MORE STABLE AIR INTO THE SYSTEM AND SUSTAIN HIGH VWS. THE JTWC INTENSITY FORECAST IS BELOW THE INTENSITY CONSENSUS, BETWEEN THE CONSENSUS AND STATISTICAL-DYNAMICAL MODEL GUIDANCE FROM SHIPS-NAVGEM AND SHIPS-GFS. OVERALL, THERE IS A LARGE DEGREE OF UNCERTAINTY IN THE TRACK AND INTENSITY FORECASTS AT LATER TAUS. HOWEVER, THE WEAKENED SYSTEM IS EXPECTED TO BE SUBJECT TO LOWER-LEVEL EASTERLY STEERING FLOW, WHICH WILL COMPETE WITH THE STRONG UPPER LEVEL JET FOR STEERING. THE JTWC FORECAST TRACK PREDICTS A DUE NORTHWARD TRACK AT THE END OF THE FORECAST PERIOD. SOME MODELS, INCLUDING NAVGEM AND GFS, NOW DEPICT ACCELERATION TO THE NORTHEAST IN LATER TAUS AS TY 34W INTERACTS WITH THE BAROCLINIC ZONE. THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH LOW CONFIDENCE.// NNNN