MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (MAYSAK) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 10W (MAYSAK), LOCATED APPROXIMATELY 579 NM SOUTH OF KADENA AB, OKINAWA, HAS TRACKED WEST-NORTHWESTWARD AT 03 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS BANDING WRAPPING INTO A LOW LEVEL CIRCULATION CENTER (LLCC) OBSCURED BY FLARING DEEP CONVECTION. A 291001Z MHS 89 GHZ MICROWAVE IMAGE SHOWS DEEP BANDING WRAPPING INTO THE SYSTEM FROM THE WEST. A 291302Z BULLSEYE METOP-B ASCAT IMAGE PLACES GOOD CONFIDENCE IN THE INITIAL POSITION AND SHOWS STRONGER WINDS IN THE NORTHEASTERN QUADRANT OF THE SYSTEM. BASED ON A 291130Z ADVANCED DVORAK TECHNIQUE ESTIMATE OF T3.4 (53 KTS) AND MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T3.5-4.0 (55-65 KTS) BY PGTW, RJTD, RCTP, AND KNES, THE INITIAL INTENSITY IS SET AT 55 KTS WITH GOOD CONFIDENCE. ENVIRONMENTAL ANALYSIS REVEALS LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), WARM (30-31 CELSIUS) SEA SURFACE TEMPERATURES (SST), AND HIGH OCEAN HEAT CONTENT (OHC) VALUES. ANIMATED WATER VAPOR IMAGERY REVEALS THAT THE TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL TO THE NORTH-NORTHEAST HAS BEGUN TO ENHANCE THE POLEWARD OUTFLOW. PAIRED WITH THE PREVIOUSLY ROBUST EQUATORWARD OUTFLOW, THE ENVIRONMENT IS FAVORABLE FOR CONTINUED DEVELOPMENT. TS 10W IS TRACKING SLOWLY NORTHWESTWARD WITHIN AN UNCERTAIN STEERING ENVIRONMENT. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. WIND RADII HAVE BEEN UPDATED BASED ON THE AFOREMENTIONED ASCAT DATA. B. IN THE NEAR TERM, TS 10W IS EXPECTED TO TRACK GENERALLY NORTHWARD AS A STEERING RIDGE TO THE EAST REORIENTS. AFTER TAU 12, THE SYSTEM WILL BEGIN TO FOLLOW A NORTH-NORTHWESTWARD TRACK ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR). THROUGH TAU 72, THE ENVIRONMENT IS FORECAST TO REMAIN FAVORABLE FOR INTENSIFICATION. DUAL CHANNEL OUTFLOW, LOW VWS, AND WARM SSTS WILL ALLOW TS 10W TO INTENSIFY TO A PEAK INTENSITY OF 115 KTS BY TAU 48. INTENSITY GUIDANCE INDICATES THAT RAPID INTENSIFICATION MAY OCCUR IN THE NEAR TERM. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT THROUGH TAU 48 WITH A CROSS-TRACK SPREAD OF 91 NM. HOWEVER, MODEL SPREAD INCREASES TO 140 NM BY TAU 72. ECMWF, NAVGEM, UKMET, AND JGSM SOLUTIONS TRACK TO THE WEST OF THE MULTI-MODEL CONSENSUS WHILE GFS (DETERMINISTIC AND ENSEMBLE) AND GALWEM LIE TO THE EAST. DESPITE THE IMPROVING MODEL SPREAD FROM PREVIOUS MODEL RUNS, THERE IS ONLY FAIR CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED NEAR THE MULTI-MODEL CONSENSUS. C. IN THE EXTENDED PERIOD, A CONTINUED REORIENTATION OF THE STR WILL ALLOW TS 10W TO ROUND THE STR AXIS AND RECURVE TO A NORTH- NORTHEASTWARD TRACK AROUND 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 THE MAJORITY OF ITS STRENGTH. AROUND TAU 96, INTERACTION WITH A PASSING SHORTWAVE TROUGH WILL CAUSE UPPER-LEVEL DIVERGENCE TO DECREASE. COMBINED WITH SIGNIFICANTLY COOLER WATERS (23-27 CELSIUS), THIS INTERACTION WILL WEAKEN THE SYSTEM AS IT BEGINS EXTRATROPICAL TRANSITION AND BEGINS TO ACCELERATE TO THE NORTH-NORTHEAST. IN THE EXTENDED RANGE, THE CROSS-TRACK MODEL SPREAD IS 130 NM AT TAU 96. AFTERWARDS, AS THE SYSTEM INTERACTS WITH THE PASSING TROUGH AND BEGINS EXTRATROPICAL TRANSITION, ALONG-TRACK MODEL SPREAD ALSO INCREASES. THUS, THERE IS OVERALL FAIR CONFIDENCE IN THE JTWC FORECAST TRACK DUE TO THE CONTINUED SPREAD IN MODEL SOLUTIONS.// NNNN NNNN