MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 09W (NINE) WARNING NR 01// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION 09W (NINE), LOCATED APPROXIMATELY 501 NM EAST-NORTHEAST OF SAIPAN, CNMI, HAS TRACKED NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A CONSOLIDATING SYSTEM WITH DEEP FLARING CONVECTION SHEARED EAST-SOUTHEASTWARD OF A PARTLY OBSCURED LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON THE EIR LOOP AND LINED UP WITH A NOTCH FEATURE IN THE 011651Z SSMI MICROWAVE IMAGE. THE INITIAL INTENSITY OF 25 KNOTS IS BASED ON THE DVORAK ESTIMATE OF T1.5/25KTS FROM PGTW AND CONSISTENT WITH RECENT ASCAT DATA. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS IN AN AREA OF MODERATE (20-25 KNOT) VERTICAL WIND SHEAR (VWS) AND SUBSIDENCE CAUSED BY AN ADJACENT TUTT CELL TO THE NORTHWEST. HOWEVER, THESE ARE PARTLY OFFSET BY EXCELLENT POLEWARD OUTFLOW AND WARM (3OC) ALONG-TRACK SSTS. THE CYCLONE IS TRACKING ALONG THE SOUTHWEST PERIPHERY OF THE STR TO THE NORTHEAST. 3. FORECAST REASONING. A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE ON THIS SYSTEM AND SETS THE FORECAST PHILOSOPHY. B. TD 09W WILL CONTINUE ON ITS CURRENT TRACK THROUGHOUT THIS FORECAST. THE AFOREMENTIONED MARGINAL CONDITIONS WILL PREVAIL OVER THE NEXT 36 HOURS RESULTING IN A SLOW OR EVEN SUSTAINED INTENSIFICATION. AFTERWARD, VWS WILL RELAX AND THE TUTT CELL WILL PROPAGATE WELL AHEAD OF THE CYCLONE, ALLOWING FOR A MORE GRADUAL INTENSIFICATION. BY TAU 72, TD 09W WILL BE APPROXIMATELY 200 NM NORTH-NORTHWEST OF IWO TO AND WILL HAVE REACHED 55 KNOTS. C. BEYOND TAU 72, 09W WILL CONTINUE ON A NORTHWESTWARD TRACK UNDER THE STEERING STR TOWARD KYUSHU, JAPAN. THE FAVORABLE ENVIRONMENTAL CONDITIONS WILL STRENGTHEN THE SYSTEM TO A PEAK OF 70 KNOTS BY TAU 96. AFTERWARD, LAND INTERACTION AND INCREASING VWS WILL BEGIN TO ERODE 09W, REDUCING IT TO 55 KNOTS BY TAU 120 AS IT TRACKS JUST SOUTH OF SASEBO. THE AVAILABLE NUMERICAL MODELS ARE IN UNUSUALLY GOOD AGREEMENT FOR A DEVELOPING SYSTEM. HOWEVER, GIVEN THE DEGREE OF UNCERTAINTY IN THE INITIAL POSITION, STORM MOTION, AND INTENSIFICATION, THERE IS LOW CONFIDENCE IN THIS FIRST TRACK FORECAST TRACK FROM JTWC.// NNNN NNNN