WTPS33 PGTW 312100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 17P (LUCAS) WARNING NR 004// RMKS/ 1. TROPICAL CYCLONE 17P (LUCAS) WARNING NR 004 03 ACTIVE TROPICAL CYCLONES IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 311800Z --- NEAR 13.4S 157.2E MOVEMENT PAST SIX HOURS - 095 DEGREES AT 20 KTS POSITION ACCURATE TO WITHIN 040 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT REPEAT POSIT: 13.4S 157.2E --- FORECASTS: 12 HRS, VALID AT: 010600Z --- 14.4S 160.7E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 085 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 120 DEG/ 17 KTS --- 24 HRS, VALID AT: 011800Z --- 16.0S 163.8E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 095 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 130 DEG/ 15 KTS --- 36 HRS, VALID AT: 020600Z --- 17.9S 166.1E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 150 DEG/ 11 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 021800Z --- 19.9S 167.3E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 175 DEG/ 07 KTS --- 72 HRS, VALID AT: 031800Z --- 22.5S 167.6E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 215 DEG/ 05 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 041800Z --- 24.3S 166.3E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 230 DEG/ 06 KTS --- 120 HRS, VALID AT: 051800Z --- 25.8S 164.2E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 312100Z POSITION NEAR 13.7S 158.1E. 31JAN21. TROPICAL CYCLONE (TC) 17P (LUCAS), LOCATED APPROXIMATELY 691 NM WEST-NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED EASTWARD AT 20 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS LOW LEVEL CLOUD LINES AND SPIRAL BANDS OF CONVECTION WRAPPING INTO AN OBSCURED LOW LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE BASED ON THE CONVECTIVE FEATURES IN THE EIR LOOP AND A 311733Z SSMIS MW EYE FEATURE IN THE 37GHZ IMAGE. THE COMPACT WIND FIELD IS DERIVED FROM THE EARLIER 310951Z ASCAT-A PASS. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH HIGH CONFIDENCE AND IS IN AGREEMENT WITH A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T3.5 (55 KTS), A CIMSS ADVANCED DVORAK TECHNIQUE CURRENT INTENSITY ESTIMATE OF 53 KNOTS AND AN EARLIER 311455Z CIMSS SATELLITE CONSENSUS INTENSITY ESTIMATE OF 54 KTS. TC LUCAS IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A NEAR EQUATORIAL RIDGE AND THROUGH A FAVORABLE ENVIRONMENT WITH VERY WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES, LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS) AND ROBUST POLEWARD OUTFLOW ALOFT. THE CURRENT FAVORABLE CONDITIONS WILL BE TEMPERED BY DIMINISHING UPPER LEVEL SUPPORT AND MODERATE SHEAR, BUT TC LUCAS IS STILL EXPECTED TO GRADUALLY INTENSIFY IN THE NEAR TERM, RESULTING IN 70 KTS BY TAU 24. THEREAFTER, INCREASING VWS (GREATER THAN 30 KNOTS AFTER TAU 36) WILL LEAD TO A GRADUAL WEAKENING TREND AS THE SYSTEM BEGINS A GENERALLY SOUTHEASTWARD TRACK ALONG A BUILDING SUBTROPICAL RIDGE (STR) TO THE EAST. AFTER TAU 48, TC LUCAS WILL BEGIN A GENERALLY SOUTHWARD TRACK AS IT BEGINS TO ROUND THE STR AXIS. HIGH (>30 KTS) VWS WILL CONTINUE TO WEAKEN THE SYSTEM DURING THIS TIME. BY TAU 96 THE SYSTEM WILL ROUND THE STR AXIS AND BEGIN TO DISSIPATE OVER WATER DUE TO HIGH (>40 KTS) VWS AND COOLING SST (25-26 DEGREES CELSIUS) WHICH WILL LEAD TO FULL DISSIPATION BY TAU 120. NUMERICAL MODEL GUIDANCE IS IN POOR AGREEMENT THROUGHOUT THE LATER PORTION OF THE FORECAST PERIOD AS MODEL TRACKS DIVERGE TO A MAXIMUM 325 NM SPREAD IN SOLUTIONS AT TAU 96. THIS HIGH DEGREE OF SPREAD IN MODEL SOLUTIONS LENDS FAIR CONFIDENCE IN THE INITIAL PORTION AND LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC FORECAST TRACK, WHICH IS PLACED ALONG THE MULTI- MODEL CONSENSUS. THERE IS LARGE UNCERTAINTY IN THE TIMING OF THE UPPER LEVEL FEATURE MOVING OVER TC LUCAS, GIVING POOR CONFIDENCE IN THE TIMING OF ITS DISSIPATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 311800Z IS 15 FEET. NEXT WARNINGS AT 010300Z, 010900Z, 011500Z AND 012100Z. REFER TO TROPICAL CYCLONE 15P (ANA) WARNINGS (WTPS31 PGTW) FOR SIX-HOURLY UPDATES. REFER TO TROPICAL CYCLONE 16P (BINA) WARNINGS (WTPS32 PGTW) FOR SIX-HOURLY UPDATES.// NNNN