WDPN32 PGTW 060300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 05W (DANAS) WARNING NR 009// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 21.6N 118.3E INITIAL INTENSITY: 70 KTS GEOGRAPHIC REFERENCE: 274 NM SOUTHWEST OF TAIPEI, TAIWAN MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 07 KTS SIGNIFICANT WAVE HEIGHT: 24 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON 05W (DANAS) WITH DEEP CENTRAL CONVECTION TIGHTLY ROTATING AROUND A FULLY OBSCURED LOW-LEVEL CIRCULATION CENTER (LLCC). A SECONDARY SWATH OF CONVECTION CAN BE SEEN OFFSET OFF TO THE EAST, SOUTH OF TAIWAN. 05W HAS STARTED TO PICK UP TRACK SPEED IN THE NORTH-NORTHEASTWARD DIRECTION, AS THE STEERING PATTERN BECOMES MORE DEFINED. A 052333Z GMI 89 GHZ MICROWAVE IMAGE REVEALED A DEFINED MICROWAVE EYE WITH SPIRALING CONVECTION SURROUNDING THE SOUTHERN, WESTERN, AND NORTHERN PORTIONS OF THE CIRCULATION. ENVIRONMENTAL ANALYSIS INDICATES THAT 05W IS IN A HIGHLY FAVORABLE ENVIRONMENT CHARACTERIZED BY STRONG POLEWARD AND EASTWARD OUTFLOW, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MICROWAVE EYE IN THE MENTIONED GMI IMAGE. THE INITIAL INTENSITY OF 70 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK CURRENT STEERING MECHANISM: THE NORTHWESTERN PERIPHERY OF A DEEP LAYER NEAR-EQUATORIAL RIDGE CENTERED TO THE SOUTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T3.5 - 55 KTS RCTP: T4.0 - 65 KTS KNES: T5.0 - 90 KTS DEMS: T4.5 - 77 KTS CIMSS ADT: 51 KTS AT 060000Z CIMSS AIDT: 57 KTS AT 060000Z CIMSS DPRINT: 64 KTS AT 060000Z CIMSS DMINT: 62 KTS AT 052333Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG POLEWARD 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: TY 05W IS FORECAST TO CONTINUE TRACKING NORTH-NORTHEASTWARD ALONG THE NORTHWESTERN PERIPHERY OF THE NEAR-EQUATORIAL RIDGE TO THE SOUTHEAST THROUGH TAU 36. NEAR TAU 36, RIDGING IS EXPECTED TO BUILD IN TO THE NORTH OF THE SYSTEM, WHICH WILL INITIATE A SHARP WESTWARD TURN INTO MAINLAND CHINA. 05W WILL THEN CONTINUE ON A GENERALLY WEST-SOUTHWESTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST PERIOD AS THE REMNANT VORTEX TRACKS FURTHER INLAND. REGARDING INTENSITY, 05W IS FORECAST TO CONTINUE INTENSIFYING THROUGH TAU 12 AS THE ENVIRONMENT REMAINS HIGHLY CONDUCIVE. HOWEVER, AFTER TAU 12, INTERACTION WITH THE WESTERN COAST OF TAIWAN WILL DISRUPT THE VORTEX AND WEAKEN THE SYSTEM. THIS WEAKENING TREND IS FORECAST TO PERSIST THROUGH TAU 48 AS 05W ENTERS A POOL OF COOL WATER THAT EXTENDS SOUTHWARD, TO AROUND 28N, AND NORTHERLY SHEAR INCREASES. AFTER TAU 48, THE RUGGED TERRAIN OF EASTERN CHINA WILL CAUSE 05W TO QUICKLY WEAKEN WITH DISSIPATION FORECAST TO OCCUR NO LATER THAN TAU 96. MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 48 WITH A 101 NM CROSS-TRACK SPREAD AT TAU 48. AFTER TAU 48, MODELS BEGIN TO DIVERGE AS SOME VORTEX TRACKERS HAVE 05W MAKE A SHARP SOUTH-SOUTHWESTWARD TURN WITHIN THE TAIWAN STRAIT (NAVGEM AND GFS). THE REMAINDER OF GUIDANCE TAKES THE SYSTEM FURTHER INLAND, AND THE JTWC FOLLOWS THIS SCENARIO MORE CLOSELY. OVERALL, THE JTWC TRACK FORECAST IS PLACED WITH MEDIUM CONFIDENCE THROUGH TAU 72 AND LOW CONFIDENCE THEREAFTER. INTENSITY GUIDANCE PAINTS AN INTERESTING PICTURE, ON ONE HAND, MANY RAPID INTENSIFICATION (RI) AIDS ARE TRIGGERING AND DEPICT THE SYSTEM REACHING 95-110 KTS IN 24 HOURS. ON THE OTHER HAND, ALL NON-RI AIDS DEPICT WEAKENING FROM TAU 0. THIS IS INTERPRETED TO SHOW THAT THE CURRENT ENVIRONMENT IS FAVORABLE FOR RI, HOWEVER, TERRAIN INTERACTION WITH TAIWAN IS WHAT WILL BE THE MAIN HINDRANCE AND DISALLOW ANY FURTHER INTENSIFICATION. THE JTWC INTENSITY FORECAST IS PLACED HIGHER THAN CONSENSUS THROUGH TAU 12 AND THEN CLOSE TO CONSENSUS THEREAFTER WITH LOW CONFIDENCE. THE POSSIBILITY FOR MORE OR LESS LAND INTERACTION WITH WESTERN TAIWAN COULD HEAVILY AFFECT INTENSITIES AS 05W TRAVERSES THE STRAIT. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN