MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (HALONG) WARNING NR 35// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 11W (HALONG), LOCATED APPROXIMATELY 284 NM SOUTH- SOUTHEAST OF KADENA AB, HAS TRACKED NORTH-NORTHEASTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. THE ANIMATED MULTISPECTRAL SATELLITE IMAGERY LOOP CONTINUES TO SHOW A SLIGHT DEGRADATION OF THE DEEP CONVECTION OVER THE NORTHERN PORTION OF THE LOW LEVEL CIRCULATION CENTER (LLCC), CONFIRMED BY A PARTIAL 051942Z SSMIS PASS. TY HALONG CONTINUES TO TRACK SLIGHTLY NORTH-NORTHEASTWARD, DRIVEN BY A RETROGRADING TUTT CELL TO THE NORTHEAST. ADDITIONALLY, THE TRACK SPEED HAS SLOWED SLIGHTLY DUE TO THE WEAKER INFLUENCE OF THE SUBTROPICAL RIDGE (STR), CURRENTLY EAST OF THE STORM, BECAUSE OF THE INFLUENCE OF THE AFOREMENTIONED TUTT. THE SUBSIDENCE ASSOCIATED WITH THE TUTT ALONG WITH MODERATE (20 KNOTS) VERTICAL WIND SHEAR (VWS) TO THE NORTHEAST OF THE SYSTEM ARE OFFSET BY THE GOOD EQUATORWARD OUTFLOW. THIS, IN ADDITION TO THE FAIRLY GOOD AGREEMENT IN THE DVORAK CURRENT INTENSITY FROM RJTD AND PTGW, LEADS TO JTWC MAINTAINING THE INITIAL INTENSITY OF 80 KNOTS. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE PREVIOUS PROGNOSTIC REASONING. B. THE SYSTEM WILL CONTINUE TO TRACK NORTH-NORTHEASTWARD THROUGH TAU 24 AS THE TUTT TO THE NORTHEAST CONTINUES TO PULL THE SYSTEM SLIGHTLY TO THE EAST. BEYOND TAU 36, THE TUTT CELL TRACKS NORTHEAST AHEAD OF THE STORM AND BECOMES ABSORBED IN THE WESTERLIES. THE STR TO THE EAST OF TY 11W WILL REORIENT SLIGHTLY AS THE TUTT CELL RETROGRADES TO THE NORTH AND BECOME THE MAIN STEERING INFLUENCE OF THE SYSTEM. TAU 48 AND BEYOND, THERE CONTINUES TO BE SOME DISAGREEMENT IN MODELED FORECAST TRACK, WITH JENI AND NAVGEM CONTINUING TO DRIVE THE SYSTEM SLIGHTLY MORE TO THE WEST DUE TO A WEAK STEERING ENVIRONMENT AS THEY FAVOR A BUILDING OF A STR WEST OF THE SYSTEM, OVER EASTERN CHINA AND INTO THE YELLOW SEA. HOWEVER, NAVGEM HAS SLOWLY BACKED DOWN ON THE STRENGTH OF THAT STR. GFS CONTINUES TO BE THE FAVORED MODEL FOR BOTH TRACK AND SPEED DUE THE REBUILDING OF THE STR EAST OF THE SYSTEM. EXPECT THAT THE TRACK SPEED OF THE STORM TO MAINTAIN THROUGH TAU 72 AS THE STR WILL DRIVE THE STORM SLIGHTLY TO THE NORTHWEST BEFORE ROUNDING THE STR. THERE IS STILL SIGNIFICANT AMBIGUITY IN THE UPPER LEVEL ANALYSIS WITH REGARD TO THE DRIVING FACTOR UP TO TAU 72. REGARDLESS, AS THE SYSTEM BEGINS TO ROUND THE STR TO THE EAST FROM TAU 48 TO 72, EXPECT THE SYSTEM TO BEGIN EXTRATROPICAL TRANSITION AND WEAKEN. C. HALONG WILL MAKE LANDFALL IN SOUTHERN JAPAN AFTER TAU 72 AS THE SYSTEM STARTS TO BE ABSORBED BY THE MID-LATITUDE WESTERLIES. TS 11W WILL SPEED UP AND CONTINUE TO WEAKEN WITH THE VWS TO INCREASE AND TOPOGRAPHICAL INFLUENCE OF THE MOUNTAINOUS AREAS OF SHIKOKU AND WESTERN HONSHU WEAKEN THE SYSTEM. EXPECT COMPLETION OF EXTRATROPICAL TRANSITION AFTER THE SYSTEM TRACKS ACROSS SOUTHERN JAPAN INTO THE SEA OF JAPAN. WHILE THE MODELS ARE IN FAIRLY TIGHT AGREEMENT OVER THE NEXT 48 HOURS, THE BIFURCATION OF THE MODELS IN THE LATER TAUS AND THE COMPLEX UPPER-LEVEL ENVIRONMENT LEADS TO AN OVERALL LOW CONFIDENCE IN JTWC'S FORECAST TRACK.// NNNN NNNN