WTPS32 PGTW 260300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE WARNING// RMKS/ 1. TROPICAL CYCLONE 17P (IRIS) WARNING NR 006 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 260000Z --- NEAR 16.6S 158.1E MOVEMENT PAST SIX HOURS - 200 DEGREES AT 06 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 - 095 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 085 NM NORTHWEST QUADRANT REPEAT POSIT: 16.6S 158.1E --- FORECASTS: 12 HRS, VALID AT: 261200Z --- 18.1S 158.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 170 DEG/ 09 KTS --- 24 HRS, VALID AT: 270000Z --- 19.8S 158.5E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 135 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 165 DEG/ 09 KTS --- 36 HRS, VALID AT: 271200Z --- 21.5S 159.0E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 215 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 165 DEG/ 05 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 280000Z --- 22.4S 159.3E 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 - 145 NM NORTHEAST QUADRANT 195 NM SOUTHEAST QUADRANT 235 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 255 DEG/ 02 KTS --- 72 HRS, VALID AT: 290000Z --- 22.6S 158.6E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 260300Z POSITION NEAR 17.0S 158.1E. TROPICAL CYCLONE 17P (IRIS), LOCATED APPROXIMATELY 560 NM NORTHWEST OF NOUMEA, NEW CALEDONIA, HAS TRACKED SOUTH- SOUTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED MULTI-SPECTRAL (MSI) SATELLITE IMAGERY SHOWS FLARING DEEP CONVECTION DISPLACED TO THE NORTHEAST OF A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC IN THE MSI LOOP. THE INITIAL INTENSITY OF 35 KNOTS IS HEDGED ON THE UPPER END OF DVORAK CURRENT INTENSITY ESTIMATES OF T2.0 FROM PGTW AND KNES. UPPER LEVEL ANALYSIS REVEALS THAT TC 17P HAS GOOD POLEWARD OUTFLOW HOWEVER, NO ORGANIZED EQUATORWARD OUTFLOW. ENVIRONMENTAL ANALYSIS SHOWS THAT THE SYSTEM IS IN AN AREA OF LOW (5-10 KNOTS) VERTICAL WIND SHEAR AND IS TRACKING THROUGH WARM (28-29 CELSIUS) SEA SURFACE TEMPERATURES. INITIALLY, TC 17P IS FORECAST TO CONTINUE TRACKING ALONG THE WESTERN EXTENT OF THE NEAR EQUATORIAL RIDGE LOCATED TO THE EAST. AFTER TAU 48, THE BUILDING SUB TROPICAL RIDGE TO THE SOUTH WILL TAKE OVER AS THE PRIMARY STEERING FEATURE AND WILL CAUSE TC IRIS TO DEFLECT WESTWARD. THE SYSTEM IS FORECAST TO SLOWLY INTENSIFY UNDER MARGINALLY FAVORABLE CONDITIONS THROUGH TAU 36, REACHING A PEAK OF 45 KNOTS. AFTER TAU 36, VERTICAL WIND SHEAR WILL INCREASE AND CAUSE THE SYSTEM TO WEAKEN, BECOMING A 30 KNOT SYSTEM BY TAU 72. AVAILABLE MODEL GUIDANCE IS IN POOR AGREEMENT WITH SUBSTANTIAL VARIATIONS IN BOTH THE TIMING AND SHARPNESS OF THE TURN TO THE WEST. THE LARGE VARIATIONS IN THE MODEL GUIDANCE LEND OVERALL LOW CONFIDENCE IN THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 260000Z IS 14 FEET. NEXT WARNINGS AT 260900Z, 261500Z, 262100Z AND 270300Z.//