WDPN31 PGTW 120300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (UTOR) WARNING NR 14// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 11W (UTOR), LOCATED APPROXIMATELY 115 NM NORTHWARD OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS THE DEEP CONVECTION OF TY 11W HAS BECOME SIGNIFICANTLY MORE DISORGANIZED AS THE LOW LEVEL CIRCULATION CENTER (LLCC) TRACKS OVER THE 6,000 TO 8,000 FOOT PEAKS OF WESTERN LUZON. HOWEVER, CONVECTION HAS BEEN STEADILY REBUILDING IN THE SOUTHWESTERN QUADRANT AS THE SYSTEM BEGINS TO EMERGE IN THE SOUTH CHINA SEA. THE CURRENT POSITION IS BASED ON THE ABOVE MSI AND FIX POSITIONS FROM PGTW AND RJTD WITH GOOD CONFIDENCE. THIS POSITION IS FURTHER SUPPORTED BY A 112211Z TRMM 37GHZ IMAGE WHICH DEPICTS THE TIGHTLY CURVED BANDING AND THE WARM CENTER OF TY 11W. THE INITIAL INTENSITY IS ESTIMATED TO BE 90 KNOTS BASED ON THE MSI DEPICTION AND MICROWAVE DATA, WITH NO RELIABLE DVORAK INTENSITY AVAILABLE WHILE THE SYSTEM IS OVER LAND. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM REMAINS IN A FAVORABLE ENVIRONMENT JUST SOUTHWEST OF AN ANTICYCLONE, WITH DIFFLUENCE ALOFT, LIGHT (10 KNOTS) VERTICAL WIND SHEAR AND EXCELLENT RADIAL OUTFLOW DEPICTED IN ANIMATED WATER VAPOR IMAGERY. TY 11W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL STEERING RIDGE (STR) TO THE NORTH. UPPER-LEVEL SOUNDING DATA THROUGHOUT THE REGION CONFIRMS THE STEERING STR REMAINS FIRMLY ENTRENCHED. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TY 11W WILL CONTINUE TO WEAKEN OVER THE NEXT SIX TO TWELVE HOURS AS THE LLCC AND EASTERN PERIPHERY OF THE SYSTEM MOVES AWAY FROM LUZON. THE SYSTEM WILL CONTINUE TRACKING WESTWARD TO WEST- NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF THE CURRENT STEERING RIDGE THROUGH TAU 36, AFTER WHICH A SLIGHT POLEWARD DEFLECTION AND STAIR-STEP TRACK WILL OCCUR IN RESPONSE TO A WEAK TRANSIENT SHORT- WAVE TROUGH (SWT) TO THE NORTH. DYNAMICAL MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE TRACK THROUGH TAU 72, EXCEPT FOR THE JAPANESE GLOBAL ENSEMBLE MEAN WHICH TIGHTLY RECURVES TY 11W BACK TO THE EAST AFTER TAU 48. THE UKMET MODEL ALSO HAS A PRONOUNCED POLEWARD TURN BEGINNING AT TAU 48, BUT REMAINS REASONABLY CLOSE TO THE REST OF THE CONSENSUS GROUPING. OVERALL ENVIRONMENTAL CONDITIONS SHOULD REMAIN FAVORABLE AS THE SYSTEM TRAVERSES THE SOUTH CHINA SEA. ADDITIONALLY, THE APPROACHING SWT MAY PROVIDE ADDITIONAL OUTFLOW AND OFFSET THE EFFECTS OF COOLER WATERS AS TY 11W APPROACHES SOUTHERN CHINA. THEREFORE, THE INTENSITY FORECAST CALLS FOR STEADY INTENSIFICATION UP THROUGH TAU 48. TY 11W WILL MAKE LANDFALL AFTER TAU 48 TO WEST- SOUTHWEST OF HONG KONG, AND BEGIN A RAPID DISSIPATION. BASED ON THE GENERALLY TIGHT GROUPING OF CONSENSUS MODELS, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST IN THE SHORT- TO MID- TERM. C. TY UTOR IS FORECAST TO RESUME A WEST-NORTHWESTERLY TRACK BY TAU 72 AND DISSIPATE OVER LAND BY TAU 96. IN THE LONGER RANGE 96- AND 120-HOUR PERIOD, THERE IS MORE SPREAD AMONG THE CONSENSUS AS THE EUROPEAN MODELS, ECMWF AND UKMET, TAKE A POLEWARD TRACK THROUGH A WEAKNESS IN THE STR TO THE EAST. HOWEVER, THE REST OF THE CONSENSUS PACKAGE HAS BEEN EXCEPTIONALLY SOLID OVER THE PAST SEVERAL DAYS. THE JTWC FORECAST TRACK IS LAID SLIGHTLY FASTER AND EQUATORWARD OF THE CONSENSUS MEAN WITH HIGH CONFIDENCE BASED ON THE GOOD AGREEMENT AND PERSISTENCE OF THE MAJORITY OF THE CONSENSUS MODELS.// NNNN