MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (MAYSAK) WARNING NR 014// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 10W (MAYSAK), LOCATED APPROXIMATELY 144 NM SOUTH OF KADENA AB, OKINAWA, HAS TRACKED NORTH-NORTHWESTWARD AT 18 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN IRREGULAR CLOUD-FILLED EYE WITH SPIRAL BANDING WRAPPING FROM THE SOUTH, PLACING HIGH CONFIDENCE IN THE INITIAL POSITON AND RECENT TRACK MOTION. THE INITIAL INTENSITY OF 100 KTS IS HEDGED BETWEEN DVORAK CURRENT INTENSITY ESTIMATES OF T5.0 (90 KTS) BY RJTD AND T5.5 (102 KTS) BY PGTW/KNES/RCTP WITH GOOD CONFIDENCE. THE INTENSITY IS FURTHER SUPPORTED BY A 310507Z SATELLITE CONSENSUS ESTIMATE OF 104 KTS. UPPER LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH A STRONG POLEWARD OUTFLOW CHANNEL, GOOD EQUATORWARD OUTFLOW, AND LOW TO MODERATE VERTICAL WIND SHEAR (VWS). ADDITIONALLY, WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE VALUES AND FAVORABLE OCEAN HEAT CONTENT VALUES ARE CONDUCIVE FOR FURTHER DEVELOPMENT. THE 30/12Z-31/00Z 500MB ANALYSES INDICATE THAT THE SUBTROPICAL RIDGE (STR) HAS BUILT EAST OF THE SYSTEM WITH A STR EXTENSION TO THE NORTH. A MIDLATITUDE SHORTWAVE TROUGH HAS DEEPENED AND SHIFTED SOUTHEASTWARD OVER CENTRAL CHINA NEAR 108E. THEREFORE, TY 10W IS TRACKING NORTH- NORTHWESTWARD UNDER THE COMBINED STEERING INFLUENCE OF THE STR TO THE EAST AND THE EXTENSION TO THE NORTH. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THROUGH TAU 24, TY 10W IS FORECAST TO CONTINUE TRACKING NORTH- NORTHWESTWARD UNDER THE COMBINED STEERING INFLUENCE OF THE STR TO THE EAST AND THE STR EXTENSION TO THE NORTH. THE SYSTEM IS EXPECTED TO STEADILY INTENSIFY TO A PEAK INTENSITY OF 120 KNOTS BY TAU 24 UNDER FAVORABLE CONDITIONS. WITH THE EXCEPTION OF GALWEM, WHICH REMAINS THE SOLE OUTLIER, NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT (49 NM SPREAD IN SOLUTIONS AT TAU 24). THE ECMWF ENSEMBLE IS ALSO IN GOOD AGREEMENT WITH ALL SOLUTIONS WEST OF OKINAWA; HOWEVER, THERE IS STILL SOME UNCERTAINTY IN THE EXACT CPA FROM OKINAWA. AFTER TAU 24, THE STR EXTENSION SHOULD BEGIN TO ERODE AS THE AFOREMENTIONED DEEP MIDLATITUDE SHORTWAVE TROUGH APPROACHES FROM THE WEST. THIS EROSION IS EXPECTED TO SHIFT TY 10W TO A POLEWARD TRACK BEFORE TURNING THE SYSTEM NORTH- NORTHEASTWARD THROUGH TAU 60. DURING THIS TIME, COOLING SST, INCREASING VWS, AND LAND INTERACTION WILL STEADILY WEAKEN THE SYSTEM AFTER TAU 36. TY 10W SHOULD COMMENCE EXTRATROPICAL TRANSITION (ETT) AROUND TAU 48 AS IT INTERACTS WITH THE MIDLATITUDE TROUGH CAUSING THE SYSTEM TO RAPIDLY WEAKEN AND ACCELERATE POLEWARD AS IT BECOMES EMBEDDED WITHIN THE STRONG SOUTHERLY FLOW. ETT COMPLETION IS EXPECTED BY TAU 72 AS TY 10W TAKES ON FRONTAL CHARACTERISTICS. DUE TO THE LOW MODEL SPREAD (UNCERTAINTY), THERE IS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS POSITIONED NEAR THE MULTI-MODEL CONSENSUS.// NNNN NNNN