WTPS31 PGTW 010900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 23P (TWENTYTHREE) WARNING NR 002// RMKS/ 1. TROPICAL CYCLONE 23P (TWENTYTHREE) WARNING NR 002 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 010600Z --- NEAR 16.7S 146.8E MOVEMENT PAST SIX HOURS - 325 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 040 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE, RADAR AND SYNOPTIC DATA PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 085 NM NORTHWEST QUADRANT REPEAT POSIT: 16.7S 146.8E --- FORECASTS: 12 HRS, VALID AT: 011800Z --- 16.0S 147.1E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 050 DEG/ 02 KTS --- 24 HRS, VALID AT: 020600Z --- 15.7S 147.5E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 090 DEG/ 02 KTS --- 36 HRS, VALID AT: 021800Z --- 15.7S 148.0E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 120 DEG/ 02 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 030600Z --- 15.9S 148.4E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 115 DEG/ 01 KTS --- 72 HRS, VALID AT: 040600Z --- 16.1S 148.9E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 160 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 115 DEG/ 08 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 050600Z --- 17.6S 152.0E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 170 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 120 DEG/ 16 KTS --- 120 HRS, VALID AT: 060600Z --- 20.6S 157.9E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 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 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 230 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT --- REMARKS: 010900Z POSITION NEAR 16.5S 146.9E. 01MAR21. TROPICAL CYCLONE 23P (TWENTYTHREE), LOCATED APPROXIMATELY 59 NM EAST-NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED NORTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT THE LOW LEVEL CIRCULATION CENTER HAS BECOME A BIT ELONGATED AND MORE DISORGANIZED OVER THE PAST SIX HOURS, JUST TO THE EAST OF AN AREA OF PERSISTENT CONVECTION WHICH IS HUGGING THE COASTLINE. THE INITIAL POSITION IS PLACED WITH MODERATE CONFIDENCE, BASED PRIMARILY ON THE WEAK SIGNATURE IN ANIMATED RADAR DATA FROM THE CAIRNS RADAR, AND SURFACE OBSERVATIONS FROM A NUMBER OF SITES IN THE VICINITY, WHICH HELPS TO CONFINE THE CENTER OF CIRCULATION. SURFACE WIND DIRECTION CHANGES OVER THE PREVIOUS SIX HOURS FROM BOUGAINVILLE REEF HAVE HELPED TO CONFIRM THE GENERAL MOTION TOWARDS THE NORTHWEST, WHILE WIND SPEEDS HAVE BEEN CONSISTENTLY SUSTAINED BETWEEN 40-45 KNOTS. HOWEVER, THE STATION HAS BEEN UNDER A CONVECTIVE BAND FOR THE PAST SIX HOURS AND SO THE WIND SPEEDS ARE UNREPRESENTATIVE OF THE OVERALL INTENSITY OF THE SYSTEM. DVORAK CURRENT INTENSITY ESTIMATE FROM PGTW AND APRF OF T2.0-2.5, AND AN ADT ESTIMATE OF T2.5, PROVIDE ADDITIONAL SUPPORT TO THE INITIAL INTENSITY WITH HIGH CONFIDENCE. ENVIRONMENTAL ANALYSIS SHOWS THE SYSTEM LIES IN A MARGINALLY FAVORABLE AREA WITH MODERATE (20 KTS) OF EASTERLY VWS BEING OFFSET BY VERY WARM (29-30C) SSTS AND STRONG POLEWARD AND MODERATE EQUATORWARD OUTFLOW. THE SYSTEM IS CURRENTLY ENSCONCED IN A COMPLEX AND OVERALL WEAK STEERING PATTERN, CAUGHT BETWEEN A STRONG SUBTROPICAL RIDGE (STR) OVER CENTRAL AUSTRALIA, ANOTHER WEAKER STR NEAR NEW CALEDONIA AND BROAD NEAR EQUATORIAL RIDGE (NER) TO THE NORTH. NO MAJOR CHANGES IN THE STEERING PATTERN ARE EXPECTED OVER THE NEXT 48-72 HOURS AND THUS, TRACK MOTION IS FORECAST TO BE SLOW AND ERRATIC, THOUGH GENERALLY IN A CLOCKWISE LOOP, TOWARDS THE NORTHEAST THEN SOUTHEAST BY TAU 72. THE APPROACH OF A MAJOR SHORTWAVE TROUGH AFTER TAU 72 WILL ERODE THE STR TO THE EAST, RESULTING IN A ACCELERATING SOUTHEASTWARD TRACK ALONG THE GRADIENT BETWEEN THE STRENGTHENING NER TO THE NORTH AND THE MAJOR SHORTWAVE TROUGH. EASTERLY VWS IS EXPECTED TO DECREASE ALLOWING FOR SLOW BUT STEADY INTENSIFICATION THROUGH TAU 72. AFTER TAU 72, THE RATE OF INTENSIFICATION WILL INCREASE AS UPPER-LEVEL OUTFLOW INCREASES INTO THE DIVERGENT REGION AHEAD OF THE TROUGH. THERE IS VERY HIGH UNCERTAINTY IN THE FORECAST TRACK DUE TO THE NATURE OF THE WEAK STEERING PATTERN AND THE TIMING AND STRENGTH OF THE TROUGH AND THE SYSTEMS RESPONSE TO IT. AVAILABLE MODEL GUIDANCE IS MIXED, WITH THE GFS CONTINUING TO SHOW AN UNLIKELY NORTHWEST TRACK PARALLEL TO THE COAST THROUGH TAU 72. THE REMAINDER OF THE CONSENSUS MEMBERS SUPPORT THE SLOW LOOPING TRACK THEN ACCELERATION SOUTHEASTWARD BUT WITH SIGNIFICANT ALONG TRACK UNCERTAINTY. THE JTWC FORECAST TRACK LIES NEAR BUT MUCH SLOWER THEN THE MULIT-MODEL CONSENSUS, AND CLOSEST TO THE ECMWF SOLUTION. HOWEVER, IN LIGHT OF THE HIGH UNCERTAINTY IN THE STEERING PATTERN, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 010600Z IS 14 FEET. NEXT WARNINGS AT 011500Z, 012100Z, 020300Z AND 020900Z.// NNNN