WTPS32 PGTW 250300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 17P (IRIS) WARNING NR 002// RMKS/ 1. TROPICAL CYCLONE 17P (IRIS) WARNING NR 002 02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 250000Z --- NEAR 14.6S 158.9E MOVEMENT PAST SIX HOURS - 235 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 030 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 14.6S 158.9E --- FORECASTS: 12 HRS, VALID AT: 251200Z --- 15.4S 158.5E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 190 DEG/ 07 KTS --- 24 HRS, VALID AT: 260000Z --- 16.7S 158.3E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 175 DEG/ 08 KTS --- 36 HRS, VALID AT: 261200Z --- 18.2S 158.5E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 165 DEG/ 09 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 270000Z --- 20.0S 159.0E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 155 DEG/ 08 KTS --- 72 HRS, VALID AT: 280000Z --- 22.8S 160.3E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT 215 NM SOUTHEAST QUADRANT 225 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 250 DEG/ 01 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 290000Z --- 23.0S 159.7E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 240 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 315 DEG/ 03 KTS --- 120 HRS, VALID AT: 300000Z --- 22.1S 158.7E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 250300Z POSITION NEAR 14.8S 158.8E. TROPICAL CYCLONE 17P (IRIS), LOCATED APPROXIMATELY 573 NM WEST- NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED SOUTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED MULTI-SPECTRAL IMAGERY (MSI) DEPICTS AN EXPANSIVE AREA OF FLARING CONVECTION LOCATED TO THE NORTH OF A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MSI LOOP AND A 242254Z METOP-A ASCAT PARTIAL IMAGE. THE INITIAL INTENSITY OF 35 KNOTS IS BASED ON THE UPPER END OF DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM T2.0 TO T2.5 (30-35 KNOTS) FROM KNES AND PGTW. THE INITIAL INTENSITY IS ALSO SUPPORTED BY THE AFOREMENTIONED ASCAT IMAGE WHICH SHOWS 30 KNOT (30-34 KNOT) WIND BARBS IN THE EASTERN SEMI-CIRCLE. UPPER LEVEL ANALYSIS REVEALS THE SYSTEM HAS GOOD EQUATORWARD AND POLEWARD OUTFLOW WITH THE LATTER TAPPING INTO THE MID-LATITUDE WESTERLIES. ENVIRONMENTAL ANALYSIS SHOWS THAT TC IRIS IS CURRENTLY IN AN AREA OF LOW (5-10KTS) VERTICAL WIND SHEAR AND IS TRACKING THROUGH WARM (28-29 CELSIUS) SEA SURFACE TEMPERATURES. THE SYSTEM WILL CONTINUE TO TRACK GENERALLY SOUTHWARD ALONG THE WESTERN EXTENT OF A SUBTROPICAL RIDGE, WITH THE TRACK BECOMING SOUTHEASTWARD AFTER TAU 36. TC 17P WILL GRADUALLY INTENSIFY UNDER FAVORABLE CONDITIONS THROUGH TAU 48, REACHING A PEAK OF 55 KNOTS. AFTER TAU 48, INCREASING VWS AND COOLING SEA SURFACE TEMPERATURES WILL BEGIN TO WEAKEN THE SYSTEM. THE SYSTEM WILL CONTINUE TO TRACK SOUTHEASTWARD THROUGH TAU 72, AFTER WHICH THE CYCLONE WILL BECOME QUASI-STATIONARY BEFORE TRACKING BACK TO THE NORTHWEST AS AN EXTENSION OF A BUILDING SUBTROPICAL RIDGE OVER EASTERN AUSTRALIA TAKES OVER AS THE PRIMARY STEERING FEATURE. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 48 WHEN INDIVIDUAL CONSENSUS MEMBERS BEGIN TO VARY SIGNIFICANTLY ON THE TIMING AND SHARPNESS OF THE TURN TO THE NORTHWEST. THE JTWC TRACK FORECAST IS PLACED NEAR THE MULTI-MODEL CONSENSUS WITH OVERALL LOW CONFIDENCE DUE TO THE UNCERTAINTY IN THE MODEL GUIDANCE. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 250000Z IS 14 FEET. NEXT WARNINGS AT 250900Z, 251500Z, 252100Z AND 260300Z. REFER TO TROPICAL CYCLONE 16P (NORA) FOR FINAL WARNING (WTPS31 PGTW).//