MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (SOUDELOR) WARNING NR 12// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 13W (SOUDELOR), LOCATED APPROXIMATELY 149 NM EAST-SOUTHEAST OF SAIPAN, HAS TRACKED WEST-NORTHWESTWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS AN IMPROVED CONVECTIVE STRUCTURE WITH DEEP SPIRAL BANDING WRAPPING INTO A BANDING EYE FEATURE. A 022206Z SSMIS 91 GHZ MICROWAVE IMAGE SHOWS DEEP CONVECTION WITHIN THE NORTHERN BANDS WRAPPING AROUND THE WESTERN PERIPHERY AND INTO A CONVECTIVE CORE. A 012332Z ASCAT IMAGE REVEALS THAT THE STRONGEST WINDS ARE ALONG THE NORTHERN PERIPHERY WHICH HAS BEEN USED TO ADJUST THE CURRENT AND FORECAST WIND RADII. THE CURRENT POSITION IS BASED ON THE ASCAT BULLSEYE WHILE BEING SUPPORTED BY A PGUM RADAR FIX AND SATELLITE FIXES FROM PGTW AND RJTD WITH GOOD CONFIDENCE. THE CURRENT INTENSITY HAS BEEN INCREASED TO 60 KNOTS BASED ON AN ASSESSMENT OF DVORAK INTENSITY ESTIMATES FROM ALL AGENCIES AND SUPPORTED BY A RECENT SATCON INTENSITY ESTIMATE OF 56 KNOTS. ENVIRONMENTAL CONDITIONS REMAIN CONDUCIVE FOR RAPID DEVELOPMENT WITH EXCELLENT OUTFLOW AIDED BY THE TUTT CELL TO THE NORTHEAST, LOW (5-10 KNOTS) VERTICAL WIND SHEAR (VWS), SEA SURFACE TEMPERATURES (SSTS) FROM 30 TO 31 CELSIUS, AND HIGH OCEAN HEAT CONTENT. TS SOUDELOR IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUB-TROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 13W IS FORECAST TO TRACK GENERALLY WEST-NORTHWESTWARD THROUGHOUT THE FORECAST PERIOD UNDER THE STEERING INFLUENCE OF THE WELL-ESTABLISHED STR. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN CONDUCIVE FOR TS 13W TO UNDERGO RAPID INTENSIFICATION OVER THE NEXT 36 TO 48 HOURS. THE MAJORITY OF DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT THROUGH TAU 72; HOWEVER, THE NAVY MODELS CONTINUE TO DIVERGE SLIGHTLY TO THE NORTH. THE OVERALL SPREAD IS 185 NM AT TAU 72. BASED ON THE OVERALL STABILITY OF THE MULTI-MODEL CONSENSUS AND THE BULK OF MODEL GUIDANCE, THERE IS HIGH CONFIDENCE DURING THIS PORTION OF THE FORECAST. C. IN THE EXTENDED FORECAST, THE INTENSIFICATION RATE WILL DECREASE DUE TO REDUCED OCEAN HEAT CONTENT AND A SLIGHT INCREASE IN VWS TO MODERATE LEVELS. SSTS ARE EXPECTED TO DECREASE SLIGHTLY NEAR TAU 72 AND THEN INCREASE AGAIN BY THE END OF THE FORECAST PERIOD AS TS 13W NEARS TAIWAN. THIS SHOULD ALLOW TS SOUDELOR TO OFFSET SOME OF THE AFOREMENTIONED NEGATIVE EFFECTS. MODEL TRACK SOLUTIONS ARE IN GOOD AGREEMENT IN THE EXTENDED TAUS WITH THE EXCEPTION OF GFDN WHICH CONTINUES TO TRACK THE SYSTEM FURTHER NORTH. THE REMAINING GUIDANCE HAS A SPREAD OF ONLY 105 NM BY TAU 120. THE JTWC TRACK IS POSITIONED VERY CLOSE TO THE PREVIOUS FORECAST AND, DUE TO THE CONTINUED AGREEMENT IN THE DYNAMIC MODEL GUIDANCE, THERE IS HIGH CONFIDENCE IN THE OVERALL JTWC TRACK FORECAST.// NNNN NNNN