WTPS31 PGTW 161500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE WARNING// RMKS/ 1. TROPICAL CYCLONE 11P (WINSTON) WARNING NR 014 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 161200Z --- NEAR 17.9S 173.6W MOVEMENT PAST SIX HOURS - 055 DEGREES AT 10 KTS POSITION ACCURATE TO WITHIN 020 NM POSITION BASED ON EYE FIXED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 170 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT REPEAT POSIT: 17.9S 173.6W --- FORECASTS: 12 HRS, VALID AT: 170000Z --- 17.4S 172.1W MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 115 NM SOUTHWEST QUADRANT 115 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 075 DEG/ 06 KTS --- 24 HRS, VALID AT: 171200Z --- 17.1S 170.9W MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 105 NM SOUTHWEST QUADRANT 105 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 090 DEG/ 02 KTS --- 36 HRS, VALID AT: 180000Z --- 17.1S 170.5W MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT 145 NM SOUTHEAST QUADRANT 115 NM SOUTHWEST QUADRANT 115 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 155 DEG/ 01 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 181200Z --- 17.3S 170.4W MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 155 NM NORTHEAST QUADRANT 155 NM SOUTHEAST QUADRANT 125 NM SOUTHWEST QUADRANT 125 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 225 DEG/ 01 KTS --- 72 HRS, VALID AT: 191200Z --- 17.6S 170.7W MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT 175 NM SOUTHEAST QUADRANT 170 NM SOUTHWEST QUADRANT 170 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 250 DEG/ 02 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 201200Z --- 17.9S 171.5W MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 120 HR POSIT: 245 DEG/ 04 KTS --- 120 HRS, VALID AT: 211200Z --- 18.5S 172.9W MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT WIND RADII VALID OVER OPEN WATER ONLY --- REMARKS: 161500Z POSITION NEAR 17.8S 173.2W. TROPICAL CYCLONE (TC) 11P (WINSTON), LOCATED APPROXIMATELY 273 NM SOUTHWEST OF PAGO PAGO, HAS TRACKED NORTHEASTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS CONVECTIVE BANDING WRAPPING INTO AN AREA OF INCREASED CENTRAL CONVECTION WITH A WEAKLY DEFINED 23NM EYE, GIVING VERY HIGH CONFIDENCE TO THE INITIAL POSITION. A 160937Z SSMIS 89 GHZ MICROWAVE IMAGE ALSO SHOWS INCREASED CENTRAL CONVECTION SURROUNDING THE MICROWAVE EYE. THE INITIAL INTENSITY IS 65 KNOTS AND BASED ON DVORAK ESTIMATES FROM PGTW REPORTING T4.0 (65 KNOTS). TC WINSTON IS CURRENTLY POSITIONED IN A GOOD ENVIRONMENT FOR INTENSIFICATION WITH FAVORABLE SEA SURFACE TEMPERATURES (30 CELSIUS) AND LOW (10 TO 15 KNOTS) VERTICAL WIND SHEAR. A STRONG WESTERLY OUTFLOW CHANNEL IS ALSO SUPPORTING THE CURRENT INTENSIFICATION, TAPPING INTO A LONGWAVE TROUGH POSITIONED TO THE SOUTHEAST. A SUBTROPICAL RIDGE TO THE NORTHWEST IS STEERING THE CYCLONE ALONG AN EASTWARD TRACK. DYNAMIC MODEL GUIDANCE SUGGESTS THAT BY TAU 24 THE RIDGE WILL WEAKEN SIGNIFICANTLY PROVIDING A VERY WEAK STEERING ENVIRONMENT, AND TC WINSTON IS EXPECTED TO BECOME QUASI-STATIONARY AND REMAIN IN A WEAK STEERING ENVIRONMENT UNTIL APPROXIMATELY TAU 96 WHEN AN EAST- WEST RIDGE BEGINS TO BUILD TO THE SOUTH SENDING TC WINSTON ON A WESTWARD TRACK. ENVIRONMENTAL CONDITIONS WILL REMAIN FAVORABLE WHICH WILL SUPPORT INTENSIFICATION, AND TC WINSTON IS EXPECTED TO REACH 100 KNOTS BY TAU 48. DUE TO THE WEAK AND COMPETING STEERING ENVIRONMENT, MODEL GUIDANCE IS IN DISAGREEMENT AS THE CYCLONE BECOMES QUASI-STATIONARY; HOWEVER HAS IMPROVED WITH THE EXTENDED FORECAST TURN TO THE WEST. THIS PROVIDES LOW CONFIDENCE TO THE JTWC FORECAST TRACK BEYOND TAU 24. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 161200Z IS 24 FEET. NEXT WARNINGS AT 162100Z, 170300Z, 170900Z AND 171500Z.//