WTXS31 PGTW 010300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 003// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 003 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 010000Z --- NEAR 20.6S 119.0E MOVEMENT PAST SIX HOURS - 315 DEGREES AT 10 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY REPEAT POSIT: 20.6S 119.0E --- FORECASTS: 12 HRS, VALID AT: 011200Z --- 21.0S 117.1E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 24 HR POSIT: 250 DEG/ 09 KTS --- 24 HRS, VALID AT: 020000Z --- 21.6S 115.2E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 36 HR POSIT: 240 DEG/ 07 KTS --- 36 HRS, VALID AT: 021200Z --- 22.3S 113.8E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 265 DEG/ 05 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 030000Z --- 22.4S 112.7E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 275 DEG/ 03 KTS --- 72 HRS, VALID AT: 040000Z --- 22.3S 111.2E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 220 DEG/ 04 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 050000Z --- 23.6S 109.9E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 180 DEG/ 06 KTS --- 120 HRS, VALID AT: 060000Z --- 26.1S 110.0E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT --- REMARKS: 010300Z POSITION NEAR 20.7S 118.5E. 01FEB21. TROPICAL CYCLONE (TC) 18S (EIGHTEEN), LOCATED APPROXIMATELY 29 NM SOUTHEAST OF PORT HEDLAND, AUSTRA, HAS TRACKED NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTI- SPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SPIRAL BANDS OF CONVECTION WRAPPING INTO A WELL-DEFINED MID-LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE BASED ON THE BANDING FEATURES IN THE MSI LOOP AND PORT HEDLAND RADAR. THE INITIAL INTENSITY IS ASSESSED AT 30 KTS BASED ON MULTIPLE SURFACE OBSERVATIONS, RANGING FROM 998MB-999MB, SURROUNDING THE SYSTEM CENTER. TC 18S IS TRACKING OVER LAND THROUGH WESTERN AUSTRALIA, HOWEVER, THE ENVIRONMENT IS OVERALL MARGINALLY FAVORABLE WITH LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS) AND MODERATE UPPER LEVEL OUTFLOW ALOFT. THE PRIMARY STEERING MECHANISM IS A SUBTROPICAL RIDGE (STR) POSITIONED TO THE SOUTHWEST, IN ADDITION TO A SECONDARY STR TO THE SOUTHEAST. TC 18S IS FORECAST TO CONTINUE TRACKING OVER WESTERN AUSTRALIA, PASSING DIRECTLY OVERHEAD OF LEARMONTH, AUSTRALIA, AND INTENSIFY TO 40 KTS BY TAU 48, AFTER IT MOVES INTO THE INDIAN OCEAN. THE SYSTEM IS EXPECTED TO INTENSIFY UP TO 50 KNOTS BY TAU 96 DUE TO WARM (27-28 DEGREES CELSIUS) SEA SURFACE TEMPERATURES, COUPLED WITH CONTINUED LOW VWS AND MODERATEALY FAVORABLE UPPER LEVEL SUPPORT. THEREAFTER, MODERATE TO HIGH (20-25 KTS) VWS AND COOLER (25-26 DEGREES CELSIUS) SST WILL BE TEMPERED BY A SLIGHT INCREASE IN UPPER LEVEL DIVERGENCE AS IT TRACKS SOUTHWARD ALONG THE WESTERN PERIPHERY OF THE STEERING STR POSITIONED TO THE EAST. NUMERICAL MODEL SOLUTIONS ARE IN GOOD AGREEMENT, ON THE GENERALLY WESTWARD TRACK THROUGH TAU 96 BUT DIVERGE SLIGHTLY ON THE TIMING OF THE SOUTHWARD TURN THEREAFTER. THIS GOOD AGREEMENT IN NUMERICAL MODEL SOLUTIONS LENDS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED ON THE MULTI-MODEL CONSENSUS. HOWEVER, THERE IS ONLY FAIR CONFIDENCE IN THE INTENSITY AT THE END OF THE FORECAST DUE TO COMPETING ENVIRONMENTAL FACTORS. NEXT WARNINGS AT 010900Z, 011500Z, 012100Z AND 020300Z. // NNNN