MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (HALONG) WARNING NR 39// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 11W (HALONG), LOCATED APPROXIMATELY 224 NM EAST-SOUTHEAST OF KADENA AB, OKINAWA, JAPAN HAS TRACKED NORTH-NORTHEASTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A CLOUD-FILLED EYE WITH THINNING CONVECTION OVER THE NORTHWESTERN QUADRANT. A 0623338Z SSMIS MICROWAVE IMAGE REVEALS TIGHTLY-CURVED DEEP CONVECTIVE BANDING WRAPPING TOWARDS A WELL-DEFINED MICROWAVE EYE. THE CURRENT POSITION IS BASED ON THE MSI AND AFOREMENTIONED MICROWAVE IMAGE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY HAS REMAINED AT 90 KNOTS BASED ON CONSISTENT DVORAK INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES. ANIMATED WATER VAPOR IMAGERY CONTINUES TO SHOW A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL TO THE NORTHEAST ENHANCING THE POLEWARD OUTFLOW, WHILE A SMALLER TUTT CELL OVER THE NORTHWEST QUADRANT CAUSES UPPER-LEVEL CONVERGENCE, WEAKENING THE DEEP CONVECTION. HOWEVER, UPPER LEVEL ANALYSIS INDICATES TY 11W REMAINS IN A FAVORABLE ENVIRONMENT WITH LOW TO MODERATE VERTICAL WIND SHEAR (VWS) AND EXCELLENT EQUATORWARD OUTFLOW. TY HALONG IS CURRENTLY TRACKING NORTH-NORTHEASTWARD UNDER THE STEERING INFLUENCE OF A DEEP LAYERED SUBTROPICAL RIDGE (STR) LOCATED TO THE EAST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE PREVIOUS PROGNOSTIC REASONING. B. TY 11 IS EXPECTED TO TRACK NORTHWARD AS THE STR TO THE EAST REORIENTS THROUGH TAU 48. AFTERWARDS, TYPHOON HALONG WILL BE LOCATED ON THE NORTH-WESTERN QUADRANT OF THE STR, SHIFTING TO A NORTHEASTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST PERIOD. FAVORABLE CONDITIONS ARE EXPECTED TO PERSIST, ALLOWING TY 11W TO MAINTAIN ITS INTENSITY OVER THE NEXT 24 HOURS. BY TAU 48, THE WESTERLIES WILL BEGIN TO IMPINGE ON THE NORTHWESTERN QUADRANT OF THE SYSTEM, LEADING TO A SLOW WEAKENING TREND AND THE START OF THE EXTRA- TROPICAL TRANSITION (ETT) PROCESS. C. IN THE EXTENDED TAUS, TY HALONG WILL MAKE LANDFALL INTO SHIKOKU, JAPAN AROUND TAU 60 AS THE SYSTEM STARTS TO BECOME FURTHER ENTRENCHED WITHIN THE MID-LATITUDE WESTERLIES. THE COMBINED EFFECTS OF INCREASING VWS AND FRICTIONAL EFFECTS WILL FURTHER WEAKEN THE SYSTEM. TY 11 IS EXPECTED TO COMPLETE ETT BY TAU 120 AS THE SYSTEM MOVES INTO THE NORTHEASTERN REGION OF THE SEA OF JAPAN AND IS FULLY ABSORBED WITHIN THE MID-LATITUDE WESTERLIES. AVAILABLE MODEL GUIDANCE IS IN GOOD AGREEMENT IN THE NEAR TERM AND DIVERGES AFTER TAU 72. DUE TO VARIATIONS IN THE STEERING PATTERN AND COMPLEX UPPER- LEVEL ENVIRONMENT IN THE EXTENDED TAUS, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST.// NNNN NNNN