MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 06W (TAPAH) WARNING NR 07// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 06W (TAPAH), LOCATED APPROXIMATELY 97 NM EAST- NORTHEAST OF SAIPAN, HAS TRACKED NORTHWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS CONVECTIVE BANDS HAVE WRAPPED TIGHTER INTO THE LOW LEVEL CIRCULATION CENTER AS THE CENTRAL CONVECTION HAS CONTINUED TO DEEPEN, PUNCTUATED BY THE APPEARANCE OF A DIMPLE FEATURE - PRELUDE TO THE FORMATION OF AN EYE. THE INITIAL POSITION IS BASED ON THE ABOVE ANIMATION AND EXTRAPOLATED FROM A MICROWAVE EYE ON A 282214Z SSMI-S PASS WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS BASED ON THE 282230Z DVORAK ESTIMATE FROM PGTW. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW (05 TO 10 KNOT) VERTICAL WIND SHEAR (VWS) AND GOOD POLEWARD OUTFLOW. TY 06W IS TRACKING NORTHWARD ALONG THE WESTERN EDGE OF A MID-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST. 3. FORECAST REASONING. A. NO CHANGE TO FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 06W IS FORECAST TO TRACK NORTHWARD THROUGH TAU 12 THEN NORTHWESTWARD AS THE STR BUILDS. AFTER TAU 48, THE CYCLONE WILL CREST THE RIDGE AXIS AND TURN MORE NORTHWARD. THERE IS A 12-18 HOUR WINDOW OF CONTINUED FAVORABLE CONDITIONS FOR THE SYSTEM TO FURTHER INTENSIFY, PEAKING AT 70 KNOTS BEFORE INCREASING VWS, DIMINISHING OUTFLOW, AND COOLING SEA SURFACE TEMPERATURES (SSTS) BEGIN TO ERODE THE CYCLONE. C. IN THE EXTENDED TAUS, TY TAPAH IS FORECAST TO RE-CURVE NORTHEASTWARD AHEAD OF AN APPROACHING SHORTWAVE TROUGH. INCREASING VWS, DECREASING SSTS, AND INTERACTION WITH THE COLD BAROCLINIC ZONE WILL RAPIDLY WEAKEN THE SYSTEM, DISSIPATING IT BY TAU 96. THE DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT. THE TRACK FORECAST IS LAID EAST OF THE MULTI-MODEL CONSENSUS TO OFFSET LESS LIKELY WESTWARD OUTLIERS. DUE TO THE TIGHT GROUPING OF MODEL GUIDANCE, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. // NNNN NNNN