WTXS52 PGTW 110300 WARNING ATCG MIL 03S SIO 201211014154 2020121100 03S THREE 010 02 135 24 SATL RADR 060 T000 197S 1169E 040 R034 110 NE QD 095 SE QD 070 SW QD 030 NW QD T012 224S 1204E 035 T024 247S 1239E 025 AMP 012HR DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND 024HR DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND SUBJ: TROPICAL CYCLONE 03S (THREE) WARNING NR 010 1. TROPICAL CYCLONE 03S (THREE) WARNING NR 010 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 110000Z --- NEAR 19.7S 116.9E MOVEMENT PAST SIX HOURS - 135 DEGREES AT 24 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE AND RADAR PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT REPEAT POSIT: 19.7S 116.9E --- FORECASTS: 12 HRS, VALID AT: 111200Z --- 22.4S 120.4E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 24 HR POSIT: 125 DEG/ 20 KTS --- 24 HRS, VALID AT: 120000Z --- 24.7S 123.9E MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 110300Z POSITION NEAR 20.4S 117.8E. 11DEC20. TROPICAL CYCLONE 03S (THREE), LOCATED APPROXIMATELY 221 NM NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT 24 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT THE SYSTEM HAS INTENSIFIED, STANDING STRONG IN THE FACE OF INCREASING VERTICAL WIND SHEAR (VWS), THOUGH THE MAIN CORE OF THE DEEPEST CONVECTION IS SOMEWHAT DISPLACED SOUTHEAST FROM THE LOW-LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE, BASED ON A COMBINATION OF DATA INCLUDING A SOMEWHAT AMBIGUOUS 102356Z ASCAT-A PASS, SPIRAL BAND ANALYSIS OF THE EXPOSED LOW-LEVEL BANDS IN THE SOUTHWEST QUADRANT AND RADAR IMAGERY FROM PORT HEDLAND. BASED ON ALL AVAILABLE DATA, AT 110000Z, THE SYSTEM REMAINS OFFSHORE NORTHWEST AUSTRALIA. THE INITIAL INTENSITY IS ASSESSED AT 40 KNOTS WITH FAIR CONFIDENCE, HEDGED SLIGHTLY HIGHER THAN THE PGTW DVORAK ESTIMATE OF T2.5 (35 KNTOS) BASED ON AN ADVANCED DVORAK TECHNIQUE (ADT) ESTIMATE OF T3.0 (45 KNOTS) AND A SATELLITE CONSENUS ESTIMATE OF 42 KNOTS, WITH SUPPORT FROM THE AOREMENTIONED ASCAT-A PASS, WHICH SHOWED 40 KNOT WINDS IN THE SOUTHEAST QUADRANT. ENVIRONMENTAL ANALYSIS REVEALS THE SYSTEM LIES IN A MARGINAL ENVIRONMENT WITH WARM (30 DEG C) SSTS, LOW (10-15 KNOTS) VWS AND ROBUST POLEWARD OUTFLOW INTO THE BASE OF A MID-LATITUDE TROUGH JUST TO THE WEST. THE SYSTEM IS TRACKING RAPIDLY SOUTHEASTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER STR LOCATED TO THE NORHEAST. TC 02S IS FORECAST TO CONTINUE TRACKING SOUTHEASTWARD THROUGH THE REMAINDER OF THE FORECAST, WITH LANDFALL IMMINENT JUST SOUTHWEST OF PORT HEDLAND. ADDITIONAL INTENSIFICATION TO 45 KNOTS IS POSSIBLE PRIOR TO LANDFALL, AS THE UPPER-LEVEL OUTFLOW CONTINUES TO PROVIDE ROBUST EXHAUST, AND PRIOR TO VWS DECAPITATING THE SYSTEM OVER LAND. HOWEVER, ONCE OVER LAND, THE SYSTEM WILL RAPIDLY WEAKEN DUE TO TERRAIN INTERACTION AND INCREASING VWS, LEADING TO DISSIPATION OF WEST-CENTER AUSTRALIA BY TAU 24. NUMERICAL GUIDANCE IS IN GOOD AGREEMENT WITH CROSS-TRACK SPREAD LESS THAN 50NM THROUGH TAU 12. HOWEVER, GUIDANCE CONTINUES TO SHOW SIGNIFICANT ALONG-TRACK SPREAD THROUGH THE FORECAST PERIOD, LENDING OVERALL FAIR CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 110000Z IS 16 FEET. NEXT 0320120512 87S1058E 25 0320120518 87S1060E 25 0320120600 88S1063E 25 0320120606 90S1069E 25 0320120612 94S1074E 25 0320120618 98S1077E 25 0320120700 102S1078E 30 0320120706 106S1079E 30 0320120712 109S1079E 30 0320120718 113S1077E 30 0320120800 113S1078E 30 0320120806 112S1077E 30 0320120812 111S1081E 30 0320120818 109S1085E 45 0320120900 111S1090E 45 0320120906 116S1099E 40 0320120912 124S1106E 35 0320120918 133S1109E 35 0320121000 140S1114E 35 0320121006 148S1123E 35 0320121012 162S1136E 35 0320121018 180S1151E 35 0320121100 197S1169E 40 NNNN