WTPS32 PGTW 060300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE WARNING// RMKS/ 1. TROPICAL CYCLONE 17P (IRIS) WARNING NR 028 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 060000Z --- NEAR 19.5S 153.7E MOVEMENT PAST SIX HOURS - 045 DEGREES AT 05 KTS POSITION ACCURATE TO WITHIN 030 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT REPEAT POSIT: 19.5S 153.7E --- FORECASTS: 12 HRS, VALID AT: 061200Z --- 18.9S 153.4E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 125 NM SOUTHEAST QUADRANT 115 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 335 DEG/ 04 KTS --- 24 HRS, VALID AT: 070000Z --- 18.1S 153.0E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 330 DEG/ 06 KTS --- 36 HRS, VALID AT: 071200Z --- 17.0S 152.4E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 010 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 340 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 080000Z --- 16.2S 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 - 000 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 005 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 345 DEG/ 05 KTS --- 72 HRS, VALID AT: 090000Z --- 14.3S 151.5E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 060300Z POSITION NEAR 19.3S 153.6E. TROPICAL CYCLONE 17P (IRIS), LOCATED APPROXIMATELY 476 NM EAST- SOUTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED NORTHEASTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY REVEALS AN EXPOSED LOW LEVEL CIRCULATION CENTER WITH CONVECTION SHEARED APPROXIMATELY 90 NM TO THE SOUTHEAST. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE DUE TO THE EXPOSED LLCC. THIS POSITION IS SUPPORTED BY A 060026Z GMI 89 GHZ MICROWAVE IMAGE SHOWING BANDING WRAPPING INTO THE CENTER AND DEEP CONVECTION ISOLATED TO THE SOUTHEAST. THE INITIAL INTENSITY OF 45 KNOTS IS BASED ON THE 060000Z PGTW DVORAK FIX OF CURRENT INTENSITY (CI) T3.0 (45 KTS), ABOVE THE KNES FIX OF CI T2.5 (35 KTS), AND SUPPORTED BY A 38 KT OBSERVATION 70NM TO THE SOUTHEAST IN THE VICINITY OF THE CONVECTION. ADDITIONALLY, THE INITIAL INTENSITY IS IN CLOSE AGREEMENT WITH A 051944Z SATCON ESTIMATE OF 42 KTS. ENVIRONMENTAL ANALYSIS SHOWS MODERATE TO HIGH NORTHWESTERLY VERTICAL WIND SHEAR (20 TO 30 KNOTS) WHICH IS OFFSET BY EXCELLENT POLEWARD OUTFLOW. SEA SURFACE TEMPERATURES REMAIN FAVORABLE, BETWEEN 27 AND 28 DEGREES CELSIUS. TC 17P IS CURRENTLY TRACKING TO THE NORTHEAST IN AN UNCERTAIN STEERING ENVIRONMENT BETWEEN A NEAR EQUATORIAL RIDGE TO THE NORTH AND A MIDLEVEL RIDGE TO THE SOUTHWEST. TC 17P IS EXPECTED TO TRACK TO THE NORTHWEST UNDER THE INFLUENCE OF THE MID LEVEL STEERING FLOW AND GRADUALLY WEAKEN UNDER PERSISTENT MODERATE TO HIGH VWS AND A FORMING UPPER LEVEL LOW, WHICH WILL SUPPRESS CONVECTION, LEADING TO DISSIPATION AT 72 HOURS. OVER THE PAST SEVERAL RUNS, NUMERICAL MODEL GUIDANCE HAS INDICATED AN IMMEDIATE TURN TOWARDS THE NORTHWEST THAT HAS NOT YET MATERIALIZED. AS A RESULT, THE JTWC FORECAST TRACK IS LAID TO THE RIGHT OF AND SLOWER THAN MODEL CONSENSUS, AS THE TIMING WHEN TC 17P WILL MAKE THE EXPECTED TURN TO THE NORTHWEST IS UNCLEAR. DUE TO THE UNCERTAINTY IN TRACK SPEED AND WHEN TC 17P WILL TURN TO THE NORTHWEST, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST TRACK AND INTENSITY. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 060000Z IS 16 FEET. NEXT WARNINGS AT 060900Z, 061500Z, 062100Z AND 070300Z.//