WTPS31 PGTW 031500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 23P (NIRAN) WARNING NR 011// RMKS/ 1. TROPICAL CYCLONE 23P (NIRAN) WARNING NR 011 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 031200Z --- NEAR 14.8S 148.3E MOVEMENT PAST SIX HOURS - 090 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 020 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE, RADAR AND SYNOPTIC DATA PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT REPEAT POSIT: 14.8S 148.3E --- FORECASTS: 12 HRS, VALID AT: 040000Z --- 15.0S 149.0E MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 220 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 220 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 115 DEG/ 09 KTS --- 24 HRS, VALID AT: 041200Z --- 15.8S 150.7E MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 220 NM NORTHEAST QUADRANT 190 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 230 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 115 DEG/ 17 KTS --- 36 HRS, VALID AT: 050000Z --- 17.3S 153.8E MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 090 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 230 NM NORTHEAST QUADRANT 210 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 230 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 120 DEG/ 20 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 051200Z --- 19.2S 157.4E MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 260 NM NORTHEAST QUADRANT 200 NM SOUTHEAST QUADRANT 170 NM SOUTHWEST QUADRANT 230 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 125 DEG/ 26 KTS --- 72 HRS, VALID AT: 061200Z --- 24.6S 167.1E MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 090 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 230 NM NORTHEAST QUADRANT 190 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 200 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 120 DEG/ 28 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 071200Z --- 30.0S 178.2E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 190 NM NORTHWEST QUADRANT --- REMARKS: 031500Z POSITION NEAR 14.8S 148.5E. 03MAR21. TROPICAL CYCLONE 23P (NIRAN), LOCATED APPROXIMATELY 192 NM NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED EASTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED OVERALL CONVECTIVE SIGNATURE WITH THE MAIN FEEDER BAND WRAPPING IN FROM THE NORTH INTO AN OBSCURED LOW LEVEL CIRCULATION (LLC) THAT IS UNDER COLD OVERSHOOTING CLOUD TOPS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A DEFINED LLC FEATURE IN THE 031050Z ASCAT PASS AND CORROBORATES THE QUASI-STATIONARY MOTION OF THE CYCLONE. THE INITIAL INTENSITY OF 70KTS IS BASED ON AN OVERALL ASSESSMENT OF DVORAK INTENSITY ESTIMATES OF T4.5/77KTS (PGTW/KNES) AND T3.8/61KTS (ADT) AND REFLECTS THE SUSTAINED CONVECTIVE STRUCTURE OF THE SYSTEM. THE ENVIRONMENT IS OVERALL FAVORABLE WITH LOW (10-15KT) VERTICAL WIND SHEAR, VERY WARM (29-30C) SSTS PARTLY OFFSET BY LIMITED OUTFLOW ALOFT. TC 23P IS QUASI-STATIONARY IN A COL BETWEEN THE NEAR EQUATORIAL RIDGE (NER), EXTENDING FROM THE NORTH TO SOUTHEAST OF THE SYSTEM, AND THE SUBTROPICAL RIDGE TO THE WEST OVER AUSTRALIA. THE NER IS EXPECTED TO BUILD AND BECOME THE DOMINANT STEERING MECHANISM AND SLOWLY NUDGE THE SYSTEM OUT OF THE COL, AND BY TAU 12, DRIVE IT SOUTHEASTWARD, PASSING JUST SOUTH OF NEW CALEDONIA AROUND TAU 60, AND BY TAU 96, SHOULD BE APPROXIMATELY 440NM NORTH-NORTHEAST OF AUCKLAND, NEW ZEALAND. THE MARGINALLY FAVORABLE ENVIRONMENT WILL IMPROVE AS THE CYCLONE TRACKS POLEWARD INTO IMPROVED UPPER LEVEL OUTFLOW AND HELP FUEL A STEADY INTENSIFICATION TO A PEAK OF 105KTS BY TAU 36. AFTERWARD, INCREASING VWS AND COOLING SSTS WILL GRADUALLY ERODE THE CYCLONE DOWN TO 70KTS BY TAU 96. CONCURRENTLY, BY TAU 72, IT WILL BEGIN SUBTROPICAL TRANSITION AS IT APPROACHES THE COLD BAROCLINIC ZONE, AND BY TAU 96, WILL TRANSFORM INTO A SUBTROPICAL SYSTEM. NUMERICAL MODELS ARE IN GENERAL AGREEMENT WITH THE TRACK FORECAST BUT WITH SIGNIFICANT VARIATIONS IN ALONG TRACK SPEED IN THE NEAR- TERM AS THE TC EXITS FROM THE COL. ALSO, ACROSS TRACK SPREADS TO OVER 720NM BY TAU 96, LENDING LOW CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID CLOSE TO THE MODEL CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 031200Z IS 26 FEET. NEXT WARNINGS AT 032100Z, 040300Z, 040900Z AND 041500Z.// NNNN