WDPN32 PGTW 070300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (TAPAH) WARNING NR 004// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 18.3N 114.4E INITIAL INTENSITY: 45 KTS GEOGRAPHIC REFERENCE: 240 NM SOUTH OF HONG KONG MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS SIGNIFICANT WAVE HEIGHT: 20 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A POORLY ORGANIZED TROPICAL CYCLONE, WITH DISORGANIZED REGIONS OF DEEP CONVECTION. THE CONVECTIVE CLOUD TOPS HAVE WARMED SIGNIFICANTLY SINCE THIS MORNINGS IMPRESSIVE BURST OF ACTIVITY, AND THE AREAS OF DEEP CONVECTION HAVE BIFURCATED INTO TWO DISTINCT CLUSTERS. THE SMALLER CLUSTER IS ASSOCIATED WITH THE LOW LEVEL CIRCULATION CENTER (LLCC) WHILE THE LARGER, MORE ELONGATED CONVECTIVE BAND EXTENDS WESTWARD TOWARD HAINAN ISLAND. ANIMATED MSI AND WATER VAPOR IMAGERY ALSO REVEAL DRY MID-LEVEL AIR TO THE NORTH, INHIBITING CONVECTION ACROSS THE NORTHERN HEMISPHERE OF THE CIRCULATION AND RENDERING THE LOWER-LEVEL RAIN BANDS VISIBLE AS THEY WRAP INTO THE LLCC. A 062208Z WSF-M COLOR-ENHANCED 89GHZ IMAGE REVEALED THE TILTED VORTEX, WITH THE LLCC POSITIONED ALONG THE NORTHERN EDGE OF THE CONVECTIVE REGION, AND AN UPPER-LEVEL MICROWAVE EYE-LIKE FEATURE DISPLACED TO THE SOUTH- SOUTHWEST. THIS DEPICTION IS CONSISTENT WITH GFS MODEL-DERIVED SOUNDINGS, WHICH INDICATE APPROXIMATELY 15 KNOTS OF NORTH- NORTHEASTERLY SHEAR. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON AGREEMENT AMONG AGENCY FIX POSITIONS, ANALYSIS OF THE MICROWAVE IMAGERY AND TRACING OF THE LOW CLOUD LINES IN THE MSI. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, CONSISTENT WITH THE T3.0 FIXES FROM MULTIPLE AGENCIES. OVERALL ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE, WITH THE AFOREMENTIONED MID-LEVEL SHEAR AND RESULTANT VORTEX TILT BEING THE PRIMARY LIMITING FACTORS. INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK AND PERSISTENCE. CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST NEAR JAPAN AND EXTENDING INTO SOUTHERN CHINA. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS RJTD: T2.5 - 35 KTS RCTP: T3.0 - 45 KTS KNES: T3.0 - 45 KTS CIMSS SATCON: 43 KTS AT 062000Z CIMSS ADT: 39 KTS AT 070000Z CIMSS AIDT: 37 KTS AT 070000Z CIMSS D-MINT: 28 KTS AT 062043Z CIMSS D-PRINT: 36 KTS AT 070030Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG EQUATORWARD OTHER FACTORS: VORTEX TILT AND MODERATE MID-LEVEL NORTHERLY SHEAR. ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TROPICAL STORM (TS) 22W HAS SLOWED CONSIDERABLY OVER THE PAST FEW HOURS, WHILE CONTINUING TO TRACK ON A NEARLY DUE WEST TRAJECTORY. WHILE THE DEEP-LAYER STEERING MEAN WOULD SUGGEST A MORE WEST-NORTHWESTWARD TRACK, THE LOWER-LEVEL STEERING FLOW HAS A MORE ZONAL ORIENTATION AND THE LACK OF A DEEP AND ALIGNED VORTEX HAS RESULTED IN A MORE WESTWARD TRACK. OVERALL, THE DECELERATION IS ATTRIBUTED TO VORTEX WOBBLE DURING VORTEX ALIGNMENT, AS WELL AS A TEMPORARY WEAKENING IN THE STEERING GRADIENT AS THE PATTERN SHIFTS. HOWEVER, ALL OF THE GLOBAL MODEL GUIDANCE INDICATES THE STEERING FLOW WILL RAPIDLY BECOME MORE MERIDIONAL IN THE NEAR-TERM AND THE SYSTEM SHOULD ACCELERATE TOWARDS THE NORTHWEST IMMINENTLY. THE LATEST FRAMES OF MSI SUGGEST THE LLCC MAY ALREADY BE COMMENCING ITS TURN NORTHWARD. THE FORECAST TRACK DEPICTS THE SYSTEM ACCELERATING THROUGH LANDFALL, WHICH IS ANTICIPATED AROUND TAU 30, IN THE VICINITY OF YANGJIANG, CHINA. AFTER MOVING INLAND, THE SYSTEM WILL SLOWLY TURN WESTWARD ALONG THE SOUTHERN SIDE OF A TRANSIENT MID-LATITUDE ANTI-CYCLONE PASSING OVER NORTHERN CHINA. THE SYSTEM HAS YET TO ACHIEVE A VERTICALLY ALIGNED VORTEX, THOUGH THE LOWER-LEVEL STRUCTURE HAS STEADILY IMPROVED AND CONSOLIDATED. MODERATE MID-LEVEL NORTHERLY SHEAR IS THE MOST LIKELY CULPRIT, AS WELL AS SOME DRY MID-LEVEL AIR TO THE NORTH. MODEL GUIDANCE INDICATES BOTH OF THESE FACTORS SHOULD ABATE OVER THE NEXT 18-24 HOURS, WITH CONDITIONS BECOMING MORE CONDUCIVE SIMULTANEOUS TO AN EXPECTED INCREASE IN UPPER-LEVEL POLEWARD OUTFLOW. SHOULD THE VORTEX ALIGN PRIOR TO TAU 18, THE IMPROVED CONDITIONS WILL SUPPORT A BURST OF INTENSIFICATION AS THE SYSTEM APPROACHES LANDFALL. THE FORECAST INTENSITY PEAKS AT 60 KNOTS AT TAU 24 THOUGH THE TRUE PEAK IS LIKELY TO OCCUR NEAR LANDFALL, NEAR TAU 30 AND IS NOT CAPTURED IN THE FORECAST POINTS. AFTER LANDFALL, THE SYSTEM WILL STEADILY WEAKEN AS IT TRACKS INLAND, DISSIPATING OVER LAND NO LATER THAN TAU 72. MODEL DISCUSSION: DETERMINISTIC, ENSEMBLE AND ARTIFICIAL INTELLIGENCE (AI) MODELS REMAIN IN STRONG AGREEMENT, WITH ALL MEMBERS OF THE CONSENSUS CONFINED TO A 55NM WIDE ENVELOPE AT LANDFALL. THE JTWC FORECAST IS POSITIONED CLOSE TO THE CONSENSUS MEAN AND ECMWF-AIFS TRACKERS WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS ALSO TIGHTLY CONSTRAINED WITH THE EXCEPTION OF THE RIDE AND FRIA AIDS WHICH CONTINUE TO INDICATE RAPID INTENSIFICATION. THE REMAINDER OF THE INTENSITY CONSENSUS (HWRF, HAFS-A, CTCX, COTC, AND THE DECAY-SHIPS VERSIONS) ARE ALL IN CLOSE AGREEMENT WITH PEAK INTENSITIES BETWEEN 50- 55 KNOTS. HOWEVER, THE NON-INTERPOLATED HWRF AND THE FRIA INDICATE A PEAK INTENSITY OF 70 KNOTS AS THE SYSTEM CROSSES THE COASTLINE, AND THE NON-INTERPOLATED HAFS-A DEPICTS A 60 KNOT PEAK. THE OFFICIAL JTWC FORECAST IS SET AT 60 KNOTS AT TAU 24, BUT THE TRUE PEAK COULD POTENTIALLY BE AS HIGH AS 65-70 KNOTS JUST PRIOR TO LANDFALL. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH INTENSITY 00-72 HR: MEDIUM// NNNN