WTPS32 PGTW 050900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE WARNING// RMKS/ 1. TROPICAL CYCLONE 17P (IRIS) WARNING NR 025 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 050600Z --- NEAR 20.2S 152.9E MOVEMENT PAST SIX HOURS - 140 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT REPEAT POSIT: 20.2S 152.9E --- FORECASTS: 12 HRS, VALID AT: 051800Z --- 20.0S 152.9E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 325 DEG/ 02 KTS --- 24 HRS, VALID AT: 060600Z --- 19.6S 152.6E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 005 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 315 DEG/ 03 KTS --- 36 HRS, VALID AT: 061800Z --- 19.1S 152.1E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 015 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 335 DEG/ 03 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 070600Z --- 18.5S 151.8E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 050900Z POSITION NEAR 20.1S 152.9E. TROPICAL CYCLONE (TC) 17P (IRIS), LOCATED APPROXIMATELY 444 NM NORTH OF BRISBANE, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS DEEP AND PERSISTENT CONVECTION TO THE SOUTH OF THE LOW LEVEL CIRCULATION CENTER (LLCC) ASSOCIATED WITH TC 17P. THE INITIAL POSITION IS BASED ON A 050550Z HIMAWARI VISIBLE SATELLITE IMAGE SHOWING THE PARTIALLY EXPOSED LLCC WITH DEEP CONVECTION LOCATED TO THE SOUTH. THE INITIAL INTENSITY OF 40 KNOTS IS BASED ON A 050256Z SATCON ESTIMATE OF 42 KNOTS AND IS HEDGED SLIGHTLY ABOVE DVORAK INTENSITY ESTIMATES OF T2.5 (35 KNOTS) FROM KNES AND PGTW BASED ON IMPROVING STORM STRUCTURE. ENVIRONMENTAL ANALYSIS SHOWS MODERATE VERTICAL WIND SHEAR (20 TO 25 KNOTS) WHICH IS OFFSET BY EXCELLENT POLEWARD OUTFLOW AND MODERATE EQUATORWARD OUTFLOW. SEA SURFACE TEMPERATURES REMAIN FAVORABLE, BETWEEN 28 AND 29 DEGREES CELSIUS. TC 17P WILL MAINTAIN AN INTENSITY OF 40 KNOTS THROUGH TAU 24 BEFORE BEGINNING TO WEAKEN AND EVENTUALLY DISSIPATE BY TAU 48. DYNAMIC MODEL GUIDANCE SHOWS A GENERAL NORTHWARD TRACK BUT THE STEERING PATTERN AROUND TC 17P REMAINS VERY WEAK LEADING TO A WIDE SPREAD IN MODEL GUIDANCE. THEREFORE, THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 050600Z IS 15 FEET. NEXT WARNINGS AT 051500Z, 052100Z, 060300Z AND 060900Z.//