MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W (SIXTEEN) WARNING NR 01// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 16W (SIXTEEN), LOCATED APPROXIMATELY 581 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 19 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A CENTRAL DENSE OVERCAST FEATURE WITH FORMATIVE BANDING ON THE NORTHERN AND SOUTHERN PERIPHERY WRAPPING INTO A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC). A 171054Z SSMIS MICROWAVE IMAGE ALSO REVEALS INCREASED CENTRAL DEEP CONVECTION OBSCURING THE LLCC WITH BROKEN CONVECTIVE BANDS WRAPPING TOWARDS THE CENTER. THE CURRENT POSITION IS BASED ON THE EIR AND AFOREMENTIONED MICROWAVE IMAGE WITH LOW CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 30 KNOTS BASED ON AN OVERALL ASSESSMENT OF DVORAK INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES AS WELL AS THE CURRENT STRUCTURE. UPPER-LEVEL ANALYSIS INDICATES A POINT-SOURCE IS LOCATED OVER THE SYSTEM SUSTAINING THE INCREASED CONVECTION. WATER VAPOR IMAGERY SHOWS ENHANCED POLEWARD OUTFLOW TAPPING INTO A TUTT CELL LOCATED TO THE NORTHEAST OF THE SYSTEM. IN ADDITION TO FAVORABLE VERTICAL WIND SHEAR ENVIRONMENT, WARM SEA SURFACE TEMPERATURES (SSTS) IN THE PHILIPPINES SEA ARE CONDUCIVE FOR FURTHER DEVELOPMENT. TD 16W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST PHILOSOPHY. B. TD 16W IS FORECAST TO MAINTAIN A WEST-NORTHWESTWARD TRACK THROUGH TAU 36, BUT WILL BEGIN TURNING NORTHWARD BEYOND THIS POINT AS THE STR BEGINS TO RE-ALIGN UNDER THE INFLUENCE OF A TRANSITORY MID-LATITUDE LOW LOCATED OVER NORTHERN JAPAN. BY TAU 48, TD 16W WILL CREST THE RIDGE AND BEGIN TO TURN TO THE NORTH-NORTHEAST. TD 16W IS EXPECTED TO UNDERGO RAPID INTENSIFICATION OVER THE NEXT 36 TO 48 HOURS AS THE SSTS REMAIN VERY FAVORABLE AND VIGOROUS UPPER-LEVEL SUPPORT ALONG THE FORECAST TRACK. BY TAU 72, TD 16W IS EXPECTED TO BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT INTERACTS WITH THE MID- LATITUDE WESTERLIES. FAVORABLE UPPER-LEVEL CONDITIONS ARE EXPECTED TO PERSIST, ALLOWING TD 16W TO FURTHER INTENSIFY AND LEADING TO A PEAK INTENSITY AT 90 KNOTS BY TAU 72. C. IN THE EXTENDED TAUS, INCREASING INTERACTION WITH THE AFOREMENTIONED MID-LATITUDE WESTERLIES WILL SLOWLY WEAKEN THE STRUCTURE OF TD 16W. AROUND TAU 96, TD 16W WILL ACCELERATE NORTHEASTWARD AS IT BECOMES EMBEDDED IN THE BAROCLINIC BOUNDARY. AND WILL COMPLETE ETT BY THE END OF THE FORECAST PERIOD AS A TYPHOON STRENGTH COLD-CORE LOW. AVAILABLE MODEL GUIDANCE IS IN GOOD AGREEMENT IN THE NEAR TERM, HOWEVER INDICATES VARIATIONS AT THE RE- CURVE POINT SHOWING A 150 NM SPREAD AT TAU 48 WITH GFDN AND JAPANESE ENSEMBLE (JENS) MODELS TAKING A SHARPER EASTWARD RECURVE. DUE TO LOW INITIAL POSITION CONFIDENCE AND SOME SLIGHT DIFFERENCES IN THE EXTENT AND SPEED OF THE RECURVE SCENARIO, THERE IS OVERALL LOW CONFIDENCE IN THE FORECAST TRACK WHICH IS POSITIONED SLIGHTLY WESTWARD OF MULTI-MODEL CONSENSUS TO OFFSET THE GFDN AND JENS SOLUTIONS.// NNNN NNNN