MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (FENGSHEN) WARNING NR 006// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 26W (FENGSHEN), LOCATED APPROXIMATELY 771 NM EAST-NORTHEAST OF ANDERSEN AFB, GUAM, HAS TRACKED WEST-NORTHWESTWARD AT 16 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY INDICATES A MEDIUM-SIZED SYSTEM WITH FLARING DEEP CONVECTION AND RAIN BANDS CONSTRAINED CLOSE TO THE LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE BASED ON THE SEMI-LLC FEATURE IN THE 1632Z SSMI 85GHZ COLORIZED MICROWAVE IMAGE AND CLOSE TO A TIGHT CLUSTER OF AGENCY FIXES. THE INITIAL INTENSITY OF 35KTS IS BASED ON THE DVORAK INTENSITY ESTIMATES OF T2.5/35KTS FROM PGTW AND RJTD. THE SYSTEM IS IN, OVERALL, A FAVORABLE AREA FOR FURTHER DEVELOPMENT WITH WARM (29- 30 CELSIUS) SEA SURFACE TEMPERATURES, LOW (10-15 KNOT) VERTICAL WIND SHEAR (VWS) AND GOOD EQUATORWARD OUTFLOW. THE CYCLONE IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 26W WILL CONTINUE ON ITS CURRENT TRACK UNDER THE STR THROUGH TAU 48 WHEN IT WILL BEGIN TO TURN POLEWARD AS IT ROUNDS THE WESTERN EDGE OF THE STR AXIS. THE OVERALL FAVORABLE ENVIRONMENT WILL PROMOTE GRADUAL INTENSIFICATION TO A PEAK 85KTS BY TAU 72. THERE IS A LARGE SPREAD IN THE MODEL SOLUTIONS (270 NM AT TAU 72) WITH HIGH UNCERTAINTY IN THE TIMING OF THE RECURVE. C. AFTER TAU 72, TS 26W WILL RECURVE SHARPLY NORTHEASTWARD TO EAST-NORTHEASTWARD AND WILL GRADUALLY WEAKEN AS IT INTERACTS WITH AN APPROACHING MIDLATITUDE TROUGH AND STRONG VWS. THE SYSTEM IS EXPECTED TO BEGIN EXTRA-TROPICAL TRANSITION BY TAU 96, HOWEVER, GLOBAL MODELS ARE BUILDING A LOW-LEVEL RIDGE TO THE NORTH THAT IS EXPECTED TO IMPEDE THE FORWARD MOTION. DUE TO THIS COMPLEX, EVOLVING SYNOPTIC PATTERN, THE NUMERICAL MODEL SOLUTIONS ARE IN VERY POOR AGREEMENT, LENDING LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC FORECAST TRACK./ NNNN NNNN