WDPN31 PGTW 200300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (TEMBIN) WARNING NR 05// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 15W (TEMBIN), LOCATED APPROXIMATELY 300 NM NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 192154Z SSMIS 91 GHZ MICROWAVE IMAGE INDICATE THAT AN APPROXIMATELY 20 NM EYE HAS FORMED OVER THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE CURRENT POSITION IS BASED ON THE APPARENT EYE WITH HIGH CONFIDENCE. THE CURRENT INTENSITY IS BASED ON DVORAK ESTIMATES OF 65 TO 77 KNOTS FROM RJTD/KNES, AND PGTW RESPECTIVELY. TY 15W IS CURRENTLY UNDERGOING A RAPID INTENSIFICATION PERIOD. UPPER-LEVEL ANALYSIS INDICATES THAT A SELF-INDUCED MESO-ANTICYCLONE HAS FORMED OVER THE LLCC AND IS PROVIDING FOR EXCELLENT DIVERGENCE ALOFT AND WEAK (05-10 KNOTS) VERTICAL WIND SHEAR (VWS). ANIMATED WATER VAPOR IMAGERY SHOWS DUAL CHANNEL OUTFLOW COMPRISED OF ROBUST EQUATORWARD EXHAUST AND ENHANCED POLEWARD OUTFLOW INTO A TROPICAL UPPER- TROPOSPHERIC TROUGH (TUTT) CELL LOCATED SOUTH OF JAPAN. DURING THE PAST SIX HOURS TY 15W HAS TRACKED NORTHWARD AND IT SEEMS THAT THE BUILDING WESTERN EXTENSION OF THE NEAR EQUATORIAL RIDGE (NER) IS BEGINNING TO HAVE A STEERING EFFECT ON THE SYSTEM. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 15W WILL TRACK IN A GENERALLY POLEWARD DIRECTION DURING THE NEXT 36 HOURS UNDER THE STEERING INFLUENCE OF THE WESTERN EXTENSION OF THE NER AND TOWARDS A WEAKNESS IN THE SUBTROPICAL RIDGE (STR) CAUSED BY A TRANSITORY MID-LATITUDE TROUGH. DURING THIS TIME CONTINUED INTENSIFICATION IS EXPECTED DUE TO WARM AND DEEP OCEAN HEAT CONTENT (OHC), VERY WARM SEA SURFACE TEMPERATURES (SST) (28-31 DEGREES CELSIUS), AND DUAL CHANNEL OUTFLOW. THE MAXIMUM FAVORABLE CONDITIONS FOR OHC SEEM TO DROP OFF NEAR 20N. BY TAU 48 THE PEAK INTENSITY SHOULD BE REACHED AND BEGIN TO LEVEL OFF DUE TO THE DECREASING OHC. SST WILL REMAIN FAVORABLE BUT OUTFLOW MAY SLIGHTLY WEAKEN AS POLEWARD ENHANCEMENT INTO THE TUTT MAY BE LOST. BY TAU 48 THE TROUGH WILL EXIT THE AREA AND ALLOW SUBTROPICAL RIDGING TO BUILD OVER THE SYSTEM. TY 15W WILL THEN BE STEERED WESTWARDS BY THE SOUTHWESTERN PERIPHERY OF THE ZONAL STR. JUST AFTER TAU 72 TY 15W WILL MAKE LANDFALL OVER TAIWAN AS A SIGNIFICANT TY. C. IN THE EXTENDED FORECAST TY 15W WILL HAVE EMERGED OVER THE TAIWAN STRAIGHT AND WILL BE STEERED WESTWARD TOWARDS SOUTHEASTERN CHINA BY THE SOUTHWESTERN PERIPHERY OF THE ZONAL STR. THE SYSTEM SHOULD MAKE LANDFALL BY TAU 120 AND BEGIN TO DISSIPATE. OBJECTIVE AID GUIDANCE IS IN GOOD AGREEMENT FOR THIS FORECAST TRACK SO THERE IS HIGH CONFIDENCE. THE TRACK FORECAST IS SLIGHTLY SOUTH OF THE MODEL CONSENSUS (CONW) AFTER TAU 48 TO OFFSET THE WIDER TURNING NOGAPS AND GFS. ADDITIONALLY, THE TRACK FORECAST WAS KEEP SLIGHTLY SLOWER THAN CONW AFTER TAU 48 TO OFFSET THE MUCH FASTER GFDN.// NNNN