MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (SOUDELOR) WARNING NR 07// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 13W (SOUDELOR), LOCATED APPROXIMATELY 540 NM EAST OF SAIPAN, HAS TRACKED WESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN INCREASING MOISTURE FIELD WITH IMPROVED ORGANIZATION IN THE CONVECTION ASSOCIATED WITH A CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC). THE WATER VAPOR LOOP SHOWS POLEWARD MOVEMENT AND SOME WEAKENING TO THE TUTT CELL LOCATED NORTH OF THE CYCLONE, ALLOWING THE INCREASED ORGANIZATION. A 311632Z SSMI 37GHZ MICROWAVE IMAGE SHOWS INCREASED DEFINITION TO THE LLCC WITH THE MOST SIGNIFICANT CONVECTION ALONG THE NORTHEASTERN QUADRANT. THE CURRENT POSITION IS BASED ON THE LLCC IDENTIFIED IN THE AFOREMENTIONED IMAGERY AND SUPPORTED BY SATELLITE FIXES FROM PGTW AND RJTD. THE INITIAL INTENSITY IS HELD AT 35 KNOTS BASED ON AN ASSESSMENT OF DVORAK INTENSITY ESTIMATES FROM ALL AGENCIES AND SUPPORTED BY AN ASCAT PASS FROM 311121Z SHOWING 35 KNOT WINDS ALONG THE NORTHERN PERIPHERY. THE UPPER LEVEL ENVIRONMENT IS IMPROVING WITH THE DECREASED EFFECTS OF THE TUTT CELL ALLOWING INCREASED RADIAL OUTFLOW AND DECREASED WIND SHEAR. 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 TO THE WEST-NORTHWEST THROUGHOUT THE FORECAST PERIOD UNDER THE STEERING INFLUENCE OF THE STR. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO CONTINUE TO IMPROVE OVER THE NEXT 12 HOURS WHICH, IN ADDITION TO ALONG-TRACK SEA SURFACE TEMPERATURES (SSTS) ABOVE 30 CELSIUS, WILL SUPPORT A PERIOD OF RAPID INTENSIFICATION AFTER TAU 12. THIS INTENSIFICATION TREND WILL CONTINUE THROUGH TAU 72 AS ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE. C. IN THE EXTENDED FORECAST, INTENSIFICATION WILL BE TEMPERED BY A DECREASE IN SSTS AND OCEAN HEAT CONTENT AS WELL AS A SLIGHT INCREASE IN VWS. DYNAMIC MODEL GUIDANCE IS IN DECENT AGREEMENT THROUGH TAU 48, WITH A 130NM SPREAD AS THE CYCLONE PASSES THROUGH THE MARIANAS ISLAND CHAIN. AFTER TAU 48, THE SPREAD INCREASES DUE TO THE MODEL'S DEPICTION IN THE EXTENT OF THE STEERING RIDGE. NAVGEM, COAMPS-TC AND GFDN TRACK THE SYSTEM ON A NORTHWESTWARD TRAJECTORY AS THEY DEPICT THE STR WEAKER AND SITUATED FURTHER EAST. GFS, HWRF, AND ECMF KEEP TS SOUDELOR ON A FLATTER TRACK WITH THE STR MORE PRONOUNCED AND SET UP FURTHER WEST. THE JTWC TRACK IS POSITIONED JUST SOUTH OF THE MULTI-MODEL CONSENSUS, CLOSER TO THE GFS AND EUROPEAN MODELS BASED ON THEIR INITIALIZATION OF THE STR. DUE TO THE INCREASING MODEL SPREAD BEYOND TAU 48, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN NNNN