WTXS31 PGTW 170300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE WARNING// RMKS/ 1. TROPICAL CYCLONE 13S (URIAH) WARNING NR 008 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 170000Z --- NEAR 17.9S 81.6E MOVEMENT PAST SIX HOURS - 275 DEGREES AT 11 KTS POSITION ACCURATE TO WITHIN 010 NM POSITION BASED ON EYE FIXED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 000 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 150 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT REPEAT POSIT: 17.9S 81.6E --- FORECASTS: 12 HRS, VALID AT: 171200Z --- 18.3S 80.1E MAX SUSTAINED WINDS - 120 KT, GUSTS 145 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 070 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT 165 NM SOUTHEAST QUADRANT 200 NM SOUTHWEST QUADRANT 125 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 220 DEG/ 10 KTS --- 24 HRS, VALID AT: 180000Z --- 19.8S 78.8E MAX SUSTAINED WINDS - 130 KT, GUSTS 160 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT 180 NM SOUTHEAST QUADRANT 175 NM SOUTHWEST QUADRANT 115 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 210 DEG/ 07 KTS --- 36 HRS, VALID AT: 181200Z --- 21.0S 78.0E MAX SUSTAINED WINDS - 115 KT, GUSTS 140 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT 165 NM SOUTHEAST QUADRANT 155 NM SOUTHWEST QUADRANT 115 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 200 DEG/ 05 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 190000Z --- 22.0S 77.6E MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 145 NM SOUTHWEST QUADRANT 175 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 190 DEG/ 01 KTS --- 72 HRS, VALID AT: 200000Z --- 22.5S 77.5E MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 115 NM NORTHEAST QUADRANT 135 NM SOUTHEAST QUADRANT 135 NM SOUTHWEST QUADRANT 115 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 180 DEG/ 02 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 210000Z --- 23.1S 77.5E MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 120 HR POSIT: 165 DEG/ 04 KTS --- 120 HRS, VALID AT: 220000Z --- 24.5S 77.9E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY --- REMARKS: 170300Z POSITION NEAR 18.0S 81.2E. TROPICAL CYCLONE 13S (URIAH), LOCATED APPROXIMATELY 838 NM SOUTHEAST OF DIEGO GARCIA, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A SIGNIFICANT IMPROVEMENT IN SYSTEM STRUCTURE WITH DEEP CONVECTION WRAPPING INTO A 12 NM EYE WHICH HAS FORMED OVER THE PAST TWO HOURS. A 162244Z GPM 91 GHZ MICROWAVE IMAGE INDICATES A CONSOLIDATION OF DEEP CONVECTION AROUND A WELL-DEFINED, SYMMETRIC MICROWAVE EYE THAT PROVIDES HIGH CONFIDENCE TO THE INITIAL POSITION. TC URIAH HAS UNDERGONE RAPID INTENSIFICATION (RI) OVER THE PAST 12 HOURS SUPPORTED BY THE INCREASED CORE CONVECTION AND IMPROVED STRUCTURE. THE INITIAL INTENSITY IS ASSESSED AT 105 KNOTS, BASED ON DVORAK ESTIMATES OF T6.0 AND T5.5 FROM PGTW AND KNES, RESPECTIVELY. THE SYNOPTIC ENVIRONMENT SURROUNDING TC URIAH REMAINS SUPPORTIVE OF FURTHER NEAR-TERM INTENSIFICATION. WHILE TC URIAH IS A COMPACT SYSTEM THAT IS NEARLY COCOONED IN MID-LEVEL DRY AIR, IT HAS DEVELOPED AN UPPER-LEVEL POINT SOURCE ON TOP OF THE CORE, ENABLING A SIGNIFICANT REDUCTION IN VERTICAL WIND SHEAR, NOW LESS THAN 10 KNOTS. THIS COMBINED WITH HIGH SEA SURFACE TEMPERATURES (SSTS) AND HIGH OCEAN HEAT CONTENT, HAVE ENABLED THE RECENT RI. TC URIAH IS CURRENTLY BEING STEERED ON A GENERAL WESTWARD TRACK BY THE DEEP SUBTROPICAL RIDGE TO THE EAST. BY TAU 48, TC URIAH WILL TURN SOUTHWARD AS IT REACHES THE AXIS OF THE STEERING RIDGE. CONCURRENTLY A MID-LEVEL TRANSITORY RIDGE WILL BUILD IN SOUTH OF THE SYSTEM CREATING A COMPETING STEERING ENVIRONMENT, WHICH WILL SLOW THE TRACK SIGNIFICANTLY, BECOMING QUASI-STATIONARY BY TAU 72. TC URIAH WILL ACCELERATE SOUTHWARD ONCE AGAIN BY TAU 96 IN RESPONSE TO A DEEP- LAYER STR BUILDING TO THE NORTHEAST OF THE SYSTEM. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 72 WITH UNCERTAINTY AFTER THAT DUE TO THE WEAK STEERING ENVIRONMENT, GIVING MODERATE CONFIDENCE IN THE OVERALL JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 170000Z IS 32 FEET. NEXT WARNINGS AT 171500Z AND 180300Z.//