WDPN32 PGTW 281500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN) WARNING NR 006// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.8N 135.4E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 821 NM SOUTH-SOUTHEAST OF KADENA AB MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 13 KTS SIGNIFICANT WAVE HEIGHT: 17 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT TROPICAL STORM (TS) 06W (KHANUN) IS HAVING A HARD TIME CONSOLIDATING IN THE FACE OF PERSISTENT NORTHERLY SHEAR AND MID TO UPPER-LEVEL DRY AIR PRESSING DOWN FROM THE NORTH AND WEST. ANIMATED SHORTWAVE INFRARED IMAGERY SHOWS THE PRIMARY LOW LEVEL VORTEX IS NOW EXPOSED IN THE MIDDLE OF AN AREA OF DISORGANIZED CONVECTION FLARING AROUND THE PERIPHERY OF THE BROADER CIRCULATION. A TIMELY 281116Z GPM 36GHZ MICROWAVE IMAGE PROVIDED HIGH CONFIDENCE IN THE ASSESSMENT OF THE INITIAL POSITION AND THAT THIS VORTEX IS THE PRIMARY ONE. THE INITIAL INTENSITY REMAINS SET AT 35 KNOTS, AT THE HIGHER END OF THE AGENCY DVORAK INTENSITY ESTIMATES AND IN LINE WITH THE OBJECTIVE ESTIMATES RANGING FROM 32-41 KNOTS. THE LATEST CIMSS TOTAL PRECIPITABLE WATER (TPW) DATA SUGGESTS THE SYSTEM IS COCOONED IN A VERY MOIST ENVIRONMENT, BUT THE HIGH-RESOLUTION HAFS-A AND HWRF AS WELL AS THE GFS AND ECMWF GLOBAL MODEL FIELDS PLUS THE CIMSS UPPER-LEVEL ANALYSIS, REVEAL A WEDGE OF VERY DRY, CONVERGENT AIR IN THE MID TO UPPER-LEVELS TO THE NORTHWEST OF THE SYSTEM. THIS, ALONG WITH THE CONTINUED NORTHERLY PRESSURE IS OFFSETTING THE STRONG EQUATORWARD OUTFLOW AND SUPPORTIVE SSTS AND PRECLUDING HINDERING THE LOW-LEVEL CONSOLIDATION AND INTENSIFICATION. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER NEAR EQUATORIAL RIDGE (NER) CENTERED EAST OF GUAM. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS RJTD: T2.0 - 30 KTS RCTP: T2.5 - 35 KTS KNES: T2.0 - 30 KTS CIMSS ADT: 32 KTS AT 281130Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG EQUATORWARD OTHER FACTORS: MID TO UPPER-LEVEL DRY AIR IN THE NORTH-NORTHWEST QUADRANT OF THE CIRCULATION. ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: THROUGH THE FIRST 36 HOURS OF THE FORECAST, TS 06W IS EXPECTED TO TRACK GENERALLY TOWARDS THE NORTH-NORTHWEST ALONG THE PERIPHERY OF THE NER TO THE EAST. SHORT-TERM WOBBLES AND EXCURSIONS LEFT AND RIGHT OF THE FORECAST TRACK ARE TO BE ANTICIPATED AS THE VORTEX STRUCTURE CONTINUES TO CONSOLIDATE BUT THE OVERALL TRACK MADE GOOD WILL BE TOWARDS THE NORTH-NORTHWEST. BY TAU 36 THE STEERING PATTERN WILL BEGIN TO SHIFT, AS THE NER SLIDES TOWARDS THE SOUTHWEST, HANDING THE BATON TO THE STRONG SUBTROPICAL RIDGE (STR) LYING ON AN EAST-WEST AXIS FROM TOKYO TO SEOUL AND INTO NORTHERN CHINA. BY TAU 72, THE STR BECOMES THE PRIMARY STEERING INFLUENCE AND TS 06W WILL TURN ONTO A MORE WEST-NORTHWEST TRACK THROUGH THE REMAINDER OF THE FORECAST. TRACK SPEEDS ARE EXPECTED TO SLOW AS THE SYSTEM PASSES OKINAWA AS THE RIDGE TO THE NORTH WEAKENS AND THE SYSTEM MOVES INTO A WEAKER STEERING ENVIRONMENT. A VERY CLOSE PASSAGE TO OKINAWA IS EXPECTED BY TAU 72 WITH A LANDFALL IN THE VICINITY OF SHANGHAI FORECAST BY TAU 120. IN TERMS OF INTENSITY, THE SLOW PACE OF INTENSIFICATION IS EXPECTED TO CONTINUE FOR THE NEXT 36 TO 48 HOURS, AS THE WEDGE OF DRY MID AND UPPER-LEVEL AIR IS FORECAST TO PENETRATE FURTHER INTO THE CIRCULATION ON THE WESTERN SIDE, OFFSETTING IMPROVED POLEWARD OUTFLOW INTO A TUTT-CELL WHICH KICKS OFF AROUND TAU 18. ALL GLOBAL AND MESOSCALE MODELS AGREE THAT BY TAU 48 THE DRY AIR IS PUSHED ASIDE, AND COINCIDES WITH BOTH THE CONSOLIDATION OF THE LOW-LEVEL CORE AND THE PEAK IN THE POLEWARD OUTFLOW. THIS CONGRUENCE OF IMPROVED ENVIRONMENTAL PARAMETERS WILL ALLOW FOR A BURST OF RAPID INTENSIFICATION BETWEEN TAU 48 AND TAU 72, WITH THE INTENSITY FORECAST TO INCREASE FROM 60 TO 100 KNOTS WITHIN THIS 24 HOUR PERIOD. BY TAU 72, THE DEVELOPMENT OF AN UPPER-LEVEL ANTICYCLONE JUST NORTH OF THE SYSTEM WILL INTRODUCE EASTERLY CONVERGENT FLOW AROUND THE SYSTEM, BUT THE SYSTEM IS EXPECTED TO BE STRONG ENOUGH BY THAT TIME TO PUT UP A GOOD FIGHT AGAINST THIS MALIGN INFLUENCE, AND IS FORECAST TO CONTINUE TO STRENGTHEN SLIGHTLY PRIOR TO LANDFALL IN EASTERN CHINA. AFTER SLOWLY MOVING ASHORE SOUTH OF SHANGHAI, THE SYSTEM WILL RAPIDLY WEAKEN DUE TO TERRAIN EFFECTS AND INCREASED SHEAR. MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN VERY TIGHT AGREEMENT, WITH THE CONSENSUS MEMBERS CONSTRAINED TO A 150NM ENVELOPE AT TAU 72. THE ECMWF, WHILE STILL DEPICTED A FLATTER TRAJECTORY PATH, HAS SHIFTED POLEWARD WITH THIS RUN AND HAS CLOSED THE GAP BETWEEN IT AND THE CONSENSUS MEAN A CONSIDERABLE AMOUNT. THE REMAINDER OF THE GUIDANCE PACKAGE IS CONTAINED IN A VERY TIGHT ENVELOPE CENTERED ON OKINAWA. SPREAD GRADUALLY INCREASES TO 245NM BY TAU 120, WITH ALL BUT THE ECMWF BEGINNING TO TURN POLEWARD BY THIS POINT. ENSEMBLE MEANS HAVE ALSO CONGEALED, AND NOW ARE TIGHTLY CLUSTERED AROUND THE CONSENSUS MEAN. IN LIGHT OF THIS, CONFIDENCE IS HIGH IN THE TRACK FORECAST THROUGH TAU 72, DECREASING TO MEDIUM IN THE LONG-TERM FORECAST. INTENSITY GUIDANCE IS MIXED, WITH THE GLOBAL MODEL-BASED GUIDANCE SUCH AS SHIPS INDICATING A STEADILY AND RATHER QUICKLY INTENSIFYING SYSTEM THAT PEAKS AT TAU 72 AT JUST 75-80 KNOTS. MEANWHILE THE COAMPS-TC BASED CTR1 AID, ALONG WITH THE COAMPS-TC (GFS VERSION), ALONG WITH SEVERAL RI AIDS, INDICATE RI STARTING NOW, CONTINUING THROUGH TAU 48 TO TAU 60, WITH A PEAK OF 105 KNOTS. THE JTWC IS A BLEND OF THESE TWO EXTREMES, INTENSIFYING THE SYSTEM AT A SLOWER PACE THAN THE CONSENSUS THROUGH TAU 48, THEN JUMPING UP TO MEET THE RI AIDS AT THE PEAK AT TAU 72. IN LIGHT OF THE HIGH UNCERTAINTY IN THE GUIDANCE, CONFIDENCE IN THE INTENSITY FORECAST IS MEDIUM TO TAU 72, AND LOW THEREAFTER. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN