MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (SIX) WARNING NR 007// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION 06W (SIX), LOCATED APPROXIMATELY 109 NM NORTH OF IWO TO, HAS TRACKED WESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH FLARING CONVECTION SHEARED TO THE EAST OF THE LLCC. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC IN THE VISIBLE SATELLITE IMAGERY. THE INITIAL INTENSITY OF 25 KNOTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T1.5 (25 KNOTS) FROM BOTH PGTW AND RJTD, AND A RAW ADT ESTIMATE OF 1.5. TD 06W REMAINS IN A VERY MARGINAL ENVIRONMENT WITH MODERATE TO STRONG (20-25 KNOTS) VWS, HIGH SSTS NEAR 30 DEG C AND WEAKLY DIVERGENT UPPER-LEVEL OUTFLOW. TD 06W CONTINUES TO TRACK WESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYER STR LOCATED TO JUST SOUTHEAST OF TOKYO. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 06W WILL CONTINUE TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE STR THROUGH TAU 24 BEFORE TURNING MORE WEST- SOUTHWEST AS THE SYSTEM WEAKENS, COMING UNDER THE INFLUENCE OF THE LOWER LEVEL FLOW PATTERN. BY TAU 72, THE SYSTEM WILL LIE BETWEEN OKINAWA AND MINAMI DAITO JIMA, HAVING SLOWED SIGNIFICANTLY AS IT APPROACHES A WEAK STEERING ENVIRONMENT INDUCED BETWEEN SUBTROPICAL RIDGES TO THE NORTHEAST AND NORTHWEST. INTENSITY IS FORECAST TO REMAIN FLAT THROUGH TAU 48 UNDER THE COMPETING INFLUENCES OF HIGH SSTS AND MODERATE WESTWARD OUTFLOW OFFSET BY MODERATE TO STRONG VWS. THERE LIKELY WILL BE SHORT DURATION FLUCTUATIONS ABOVE AND BELOW 25 KNOTS AS CONVECTION FLARES AND DISSIPATES, BUT OVERALL INTENSITY WILL REMAIN STEADY THROUGH TAU 48. AFTER THIS POINT AND THROUGH TAU 72, THE SYSTEM WILL BEGIN DISSIPATING AS VWS BECOMES DOMINANT OVER THE OUTFLOW. C. BY TAU 96, TD 06W IS FORECAST TO SLOW, BECOMING NEARLY QUASI- STATIONARY SOUTH OF OKINAWA UNDER THE INFLUENCE OF A WEAK LOW-LEVEL STEERING PATTERN. AT THE SAME TIME, TD 06W IS EXPECTED TO CONTINUE WEAKENING AS A TROPICAL CYCLONE BY TAU 96 AS INCREASING VWS AND LACK OF UPPER-LEVEL OUTFLOW WILL COMBINE TO DISSIPATE THE SYSTEM BY TAU 96 JUST SOUTH OF OKINAWA NUMERICAL MODEL GUIDANCE ALL AGREE ON THE GENERAL FORECAST, BUT DIFFER IN THE EXACT TRACK, WITH A 100 NM SPREAD AT TAU 48, WITH SPREAD ABOUT 150 NM BY TAU 96. THE OFFICIAL JTWC FORECAST LIES TO THE NORTH OF THE MULTI-MODEL CONSENSUS, CLOSER TO THE GROUPING OF JGSM, ECMWF AND UKMO MODEL TRACKERS. DUE TO THE MODERATE SPREAD IN THE MODEL SOLUTIONS, THERE IS FAIR CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN