WTPS32 PGTW 031500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE WARNING// RMKS/ 1. TROPICAL CYCLONE 17P (IRIS) WARNING NR 018 02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 031200Z --- NEAR 19.1S 150.0E MOVEMENT PAST SIX HOURS - 170 DEGREES AT 13 KTS POSITION ACCURATE TO WITHIN 025 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 - 085 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT REPEAT POSIT: 19.1S 150.0E --- FORECASTS: 12 HRS, VALID AT: 040000Z --- 19.8S 150.4E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 170 NM SOUTHEAST QUADRANT 145 NM SOUTHWEST QUADRANT 085 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 130 DEG/ 03 KTS --- 24 HRS, VALID AT: 041200Z --- 20.2S 150.9E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 145 NM SOUTHWEST QUADRANT 085 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 125 DEG/ 02 KTS --- 36 HRS, VALID AT: 050000Z --- 20.4S 151.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT 145 NM SOUTHEAST QUADRANT 125 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 165 DEG/ 02 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 051200Z --- 20.7S 151.3E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 115 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 270 DEG/ 01 KTS --- 72 HRS, VALID AT: 061200Z --- 20.7S 151.0E 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 - 085 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 280 DEG/ 02 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 071200Z --- 20.6S 150.3E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 031500Z POSITION NEAR 19.3S 150.1E. TROPICAL CYCLONE 17P (IRIS), LOCATED APPROXIMATELY 274 NM EAST- SOUTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED SOUTHWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED EIR SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED DEEP CENTRAL CONVECTION THAT REMAINS DISPLACED SOUTHEAST OF THE LLC. THE INITIAL POSITION IS BASED ON A WEAK LOW REFLECTIVITY CIRCULATION FEATURE IN THE 031026Z AMSU MICROWAVE PASS. THE INITIAL INTENSITY IS BASED ON CONGRUENT DVORAK ESTIMATES FROM PGTW AND KNES OF T3.0 (45 KNOTS). UPPER LEVEL ANALYSIS INDICATES TC 17P IS IN AN AREA OF MODERATE (15-20 KNOT) NORTHWESTERLY VWS. HOWEVER, AN EXCELLENT POLEWARD OUTFLOW CHANNEL IS PARTIALLY OFFSETTING THE VWS AND PROVIDING VENTILATION TO THE DISPLACED CONVECTION. ALONG-TRACK SSTS AT 29C ARE ALSO CONDUCIVE. TC IRIS IS TRACKING ALONG THE SOUTHWEST PERIPHERY OF THE NER TO THE NORTHEAST. THE CYCLONE WILL CONTINUE ON THIS TRACK UP TO TAU 36; AFTERWARD, THE STR TO THE SOUTHWEST WILL RE-BUILD AND ONCE AGAIN COMPETE FOR STEERING, TRIGGERING ANOTHER QS STATE. BY TAU 72, THE STR WILL EXTEND TO THE SOUTH AND ASSUME STEERING, NUDGING THE CYCLONE TO TRACK SLOWLY WESTWARD. THE AFOREMENTIONED MARGINALLY FAVORABLE CONDITIONS WILL PREVAIL FOR ABOUT 24 HOURS AND MAINTAIN THE CURRENT INTENSITY. AFTERWARD, INCREASING VWS WILL MOSTLY BE RESPONSIBLE FOR A GRADUAL WEAKENING TOWARD DISSIPATION BY END OF FORECAST. THE AVAILABLE NUMERIC GUIDANCE IS SIGNIFICANTLY SPREAD AND BIFURCATED. IN VIEW OF THIS, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID SLIGHTLY SLOWER AND WESTWARD OF MODEL CONSENSUS TO OFFSET THE EASTWARD BIFURCATED TRACKS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 031200Z IS 14 FEET. NEXT WARNINGS AT 032100Z, 040300Z, 040900Z AND 041500Z.//