MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (MAYSAK) WARNING NR 006// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 10W (MAYSAK), LOCATED APPROXIMATELY 587 NM SOUTH OF KADENA AB, OKINAWA, HAS TRACKED NORTH-NORTHWESTWARD AT 06 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH FORMATIVE CONVECTIVE BANDING WRAPPING IN TOWARDS THE CENTER. THE MSI, IN CONJUNCTION WITH AN EXTRAPOLATION OF A MICROWAVE EYE FEATURE OBSERVED IN A 290427Z AMSR2 36 GHZ MICROWAVE IMAGE, LENDS GOOD CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY REMAINS AT 55KTS BASED ON MULTIAGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T3.0-3.5 (45-55 KTS) BY PGTW, RJTD, AND RCTP. ADDITIONALLY, A 290530Z ADVANCED DVORAK TECHNIQUE ESTIMATE OF 55 KTS AND A 290452Z SATELLITE CONSENSUS ESTIMATE OF 52 KTS PLACE GOOD CONFIDENCE IN THE INITIAL INTENSITY. ENVIRONMENTAL ANALYSIS SHOWS LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), AN ESTABLISHED EQUATORWARD OUTFLOW CHANNEL, AND VERY WARM (30-31 CELSIUS) SEA SURFACE TEMPERATURES (SST). THEREFORE, THE ENVIRONMENT IS HIGHLY FAVORABLE FOR CONTINUED DEVELOPMENT. HOWEVER, CONVERGENT FLOW FROM A WESTWARD PROPAGATING TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL POSITIONED EAST-NORTHEAST OF THE LLCC IS CURRENTLY LIMITING DIVERGENCE OVER THE NORTHEASTERN QUADRANT. OCEAN HEAT CONTENT (OHC) REMAINS HIGH AND CONDUCIVE FOR DEVELOPMENT DESPITE THE CURRENT SLOW TRACK SPEED OF THE SYSTEM. TS 10W IS TRACKING SLOWLY WITHIN AN UNCERTAIN STEERING ENVIRONMENT. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 10W IS FORECAST TO TRACK GENERALLY NORTHWARD AS A SUBTROPICAL RIDGE (STR) TO THE EAST REORIENTS. THROUGHOUT THIS TIME, THE ENVIRONMENT WILL REMAIN HIGHLY CONDUCIVE FOR INTENSIFICATION WITH LOW VWS, ROBUST EQUATORWARD OUTFLOW, AND VERY WARM SST. AS THE SYSTEM MOVES, THE PREVIOUSLY MENTIONED TUTT CELL WILL CEASE HINDERING THE SYSTEM AND BEGIN TO ENHANCE POLEWARD OUTFLOW. INTENSITY GUIDANCE INDICATES THAT RAPID INTENSIFICATION MAY OCCUR IN THE NEAR TERM WITH THE CURRENT FORECAST REACHING 90 KTS BY TAU 24 AS TS 10W TRACKS NORTHWARD ALONG THE BUILDING STR. AFTER TAU 36, THE SYSTEM WILL TURN SLIGHTLY TO A NORTH-NORTHWESTWARD TRACK FOLLOWING THE WESTERN PERIPHERY OF THE STR. HIGHLY FAVORABLE ENVIRONMENTAL CONDITIONS ARE EXPECTED TO PERSIST, LEADING TO A PEAK INTENSITY OF 115 KTS BY TAU 48. NUMERICAL MODEL GUIDANCE ARE IN FAIR AGREEMENT THROUGH TAU 48. HOWEVER, MODEL SPREAD INCREASES TO A CROSS-TRACK SPREAD OF 170 NM BY TAU 72. THERE ARE TWO MAJOR OUTLIERS AT THIS POINT, GFS ENSEMBLE TO THE EAST AND JGSM TO THE WEST. OF NOTE, ECMWF AND UKMET CONVERGE WEST OF THE MULTI-MODEL CONSENSUS WHILE GFS AND NAVGEM LIE TO THE EAST. THE JTWC FORECAST TRACK IS PLACED NEAR THE MULTI-MODEL CONSENSUS; HOWEVER, DUE TO THE LARGE SPREAD IN SOLUTIONS, THERE IS ONLY FAIR CONFIDENCE IN THE INITIAL PORTION OF THE FORECAST TRACK. C. IN THE EXTENDED PERIOD, A CONTINUED REORIENTATION OF THE STR WILL ALLOW TS 10W TO BEGIN TO ROUND THE STR AXIS AND RECURVE TO A NORTH-NORTHEASTWARD TRACK AFTER TAU 72. DURING THIS TIME, COOLING SSTS WILL SLIGHTLY WEAKEN THE SYSTEM BUT INCREASED TRACK SPEED, LOW VWS, AND FAVORABLE UPPER LEVEL DIVERGENCE WILL ALLOW THE SYSTEM TO MAINTAIN A STRENGTH OF 100 KTS AT TAU 96. AFTER TAU 96, SIGNIFICANTLY COOLER SST (24-28 CELSIUS) COMBINED WITH DECREASING DIVERGENT FLOW ALOFT DUE TO AN INCOMING SHORTWAVE TROUGH WILL WEAKEN TS 10W TO 70 KTS BY TAU 120 AS THE SYSTEM BEGINS EXTRATROPICAL TRANSITION. IN THE EXTENDED RANGE, THE MAJORITY OF THE MODEL SOLUTIONS ARE NEAR THE MULTI-MODEL CONSENSUS WITH THE EXCEPTION OF THE AFOREMENTIONED OUTLIERS AND GFS MODEL WHICH DIVERGES EASTWARD AFTER TAU 72. DESPITE THIS, THERE IS OVERALL FAIR CONFIDENCE IN THE JTWC FORECAST TRACK DUE TO THE LARGE SPREAD IN MODEL SOLUTIONS.// NNNN NNNN