WTPS51 PGTW 060900 WARNING ATCG MIL 18P SWP 170506073735 2017050606 18P DONNA 011 01 225 03 SATL 035 T000 134S 1641E 080 R064 020 NE QD 025 SE QD 025 SW QD 025 NW QD R050 050 NE QD 045 SE QD 060 SW QD 045 NW QD R034 140 NE QD 120 SE QD 190 SW QD 125 NW QD T012 138S 1638E 090 R064 045 NE QD 045 SE QD 040 SW QD 040 NW QD R050 085 NE QD 085 SE QD 075 SW QD 065 NW QD R034 175 NE QD 175 SE QD 165 SW QD 140 NW QD T024 150S 1636E 105 R064 050 NE QD 050 SE QD 045 SW QD 045 NW QD R050 095 NE QD 090 SE QD 075 SW QD 065 NW QD R034 180 NE QD 190 SE QD 160 SW QD 135 NW QD T036 163S 1638E 110 R064 055 NE QD 055 SE QD 050 SW QD 045 NW QD R050 100 NE QD 100 SE QD 080 SW QD 065 NW QD R034 185 NE QD 200 SE QD 165 SW QD 130 NW QD T048 177S 1643E 110 R064 050 NE QD 050 SE QD 050 SW QD 040 NW QD R050 095 NE QD 100 SE QD 085 SW QD 060 NW QD R034 175 NE QD 190 SE QD 150 SW QD 120 NW QD T072 201S 1659E 090 R064 020 NE QD 025 SE QD 025 SW QD 015 NW QD R050 065 NE QD 080 SE QD 050 SW QD 045 NW QD R034 165 NE QD 160 SE QD 125 SW QD 095 NW QD T096 233S 1687E 060 R050 080 NE QD 080 SE QD 050 SW QD 050 NW QD R034 150 NE QD 165 SE QD 125 SW QD 095 NW QD T120 270S 1742E 040 R034 250 NE QD 245 SE QD 100 SW QD 125 NW QD AMP 072HR BECOMING EXTRATROPICAL 096HR BECOMING EXTRATROPICAL 120HR EXTRATROPICAL SUBJ: TROPICAL CYCLONE 18P (DONNA) WARNING NR 011 1. TROPICAL CYCLONE 18P (DONNA) 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: 060600Z --- NEAR 13.4S 164.1E MOVEMENT PAST SIX HOURS - 225 DEGREES AT 03 KTS POSITION ACCURATE TO WITHIN 035 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 190 NM SOUTHWEST QUADRANT 125 NM NORTHWEST QUADRANT REPEAT POSIT: 13.4S 164.1E --- FORECASTS: 12 HRS, VALID AT: 061800Z --- 13.8S 163.8E MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 085 NM NORTHEAST QUADRANT 085 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 175 NM NORTHEAST QUADRANT 175 NM SOUTHEAST QUADRANT 165 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 190 DEG/ 06 KTS --- 24 HRS, VALID AT: 070600Z --- 15.0S 163.6E MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT 190 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 135 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 170 DEG/ 07 KTS --- 36 HRS, VALID AT: 071800Z --- 16.3S 163.8E MAX SUSTAINED WINDS - 110 KT, GUSTS 135 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 185 NM NORTHEAST QUADRANT 200 NM SOUTHEAST QUADRANT 165 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 160 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 080600Z --- 17.7S 164.3E MAX SUSTAINED WINDS - 110 KT, GUSTS 135 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 175 NM NORTHEAST QUADRANT 190 NM SOUTHEAST QUADRANT 150 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 150 DEG/ 07 KTS --- 72 HRS, VALID AT: 090600Z --- 20.1S 165.9E MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 165 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 125 NM SOUTHWEST QUADRANT 095 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 140 DEG/ 10 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 100600Z --- 23.3S 168.7E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 165 NM SOUTHEAST QUADRANT 125 NM SOUTHWEST QUADRANT 095 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 130 DEG/ 16 KTS --- 120 HRS, VALID AT: 110600Z --- 27.0S 174.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL RADIUS OF 034 KT WINDS - 250 NM NORTHEAST QUADRANT 245 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 125 NM NORTHWEST QUADRANT --- REMARKS: 060900Z POSITION NEAR 13.5S 164.0E. TROPICAL CYCLONE (TC) 18P (DONNA), LOCATED APPROXIMATELY 354 NM NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED SOUTHWESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN OVERALL WEAKENING TREND DESPITE A RECENT RESURGENCE OF DEEP CONVECTION AND CURVED BANDING. A 060514Z SSMIS 37 GHZ IMAGE INDICATES AN ORGANIZED LOW-LEVEL CIRCULATION CENTER WITH SHALLOW BANDING WRAPPING INTO A WELL-DEFINED MICROWAVE EYE FEATURE, WHICH SUPPORTS THE CURRENT POSITION WITH GOOD CONFIDENCE BUT EVIDENCES A QUASI-STATIONARY TRACK MOTION. THE CURRENT INTENSITY IS ASSESSED AT 80 KNOTS BASED ON AN AVERAGE OF DVORAK ESTIMATES RANGING FROM 4.0 TO 5.0 REFLECTING THE OVERALL WEAKENING TREND. TC 18P IS CURRENTLY LOCATED WITHIN A COMPETING STEERING ENVIRONMENT BETWEEN A WEAK SUBTROPICAL RIDGE (STR) OVER NORTHEAST AUSTRALIA AND A STRONG STR TO THE EAST. THE WESTERN STR IS FORECAST TO WEAKEN SIGNIFICANTLY AS A DEEP MIDLATITUDE TROUGH DEEPENS ACROSS THE CORAL SEA, WHICH WILL ALLOW THE EASTERN STR TO BECOME THE DOMINANT STEERING INFLUENCE WITHIN THE NEXT 24 TO 36 HOURS. TC DONNA IS FORECAST TO INTENSIFY TO A PEAK OF 110 KNOTS UNDER FAVORABLE CONDITIONS TO INCLUDE WARM SST, LOW VERTICAL WIND SHEAR (VWS) AND ROBUST POLEWARD OUTFLOW. AFTER TAU 36, TC 18P SHOULD BEGIN TO ACCELERATE SOUTHWARD AS IT TRACKS ALONG THE WESTERN PERIPHERY OF THE STR. GRADUAL WEAKENING SHOULD OCCUR AS THE SYSTEM TRACKS OVER COOLER SST. NEAR TAU 72, TC 18P WILL BEGIN EXTRA-TROPICAL TRANSITION AS IT INTERACTS WITH THE MIDLATITUDE WESTERLIES AND A WEAK BAROCLINIC ZONE. THE SYSTEM WILL ACCELERATE SOUTHEASTWARD AFTER TAU 72 AS IT COMPLETES EXTRA-TROPICAL TRANSITION AND BECOMES EMBEDDED WITHIN THE MIDLATITUDE WESTERLIES. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. DURING THE EXTENDED PERIOD, TC 18P WILL WEAKEN RAPIDLY DUE TO INCREASING VWS AND COOL SST UNDER 26C. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 060600Z IS 30 FEET. NEXT WARNINGS AT 061500Z, 062100Z, 070300Z AND 070900Z.// 1817042906 105S1604E 15 1817042912 108S1612E 15 1817042918 110S1620E 15 1817043000 112S1629E 15 1817043006 113S1637E 15 1817043012 116S1644E 15 1817043018 118S1654E 15 1817050100 119S1676E 15 1817050106 121S1692E 20 1817050112 126S1696E 25 1817050118 127S1702E 30 1817050200 128S1707E 30 1817050206 129S1707E 30 1817050212 130S1712E 30 1817050218 130S1714E 40 1817050300 128S1717E 50 1817050306 127S1712E 55 1817050306 127S1712E 55 1817050312 128S1705E 55 1817050312 128S1705E 55 1817050318 128S1696E 65 1817050318 128S1696E 65 1817050318 128S1696E 65 1817050400 125S1686E 75 1817050400 125S1686E 75 1817050400 125S1686E 75 1817050406 125S1681E 80 1817050406 125S1681E 80 1817050406 125S1681E 80 1817050412 126S1676E 85 1817050412 126S1676E 85 1817050412 126S1676E 85 1817050418 129S1668E 85 1817050418 129S1668E 85 1817050418 129S1668E 85 1817050500 130S1662E 85 1817050500 130S1662E 85 1817050500 130S1662E 85 1817050506 134S1656E 90 1817050506 134S1656E 90 1817050506 134S1656E 90 1817050512 137S1649E 90 1817050512 137S1649E 90 1817050512 137S1649E 90 1817050515 135S1646E 90 1817050515 135S1646E 90 1817050515 135S1646E 90 1817050518 133S1645E 90 1817050518 133S1645E 90 1817050518 133S1645E 90 1817050600 132S1643E 85 1817050600 132S1643E 85 1817050600 132S1643E 85 1817050606 134S1641E 80 1817050606 134S1641E 80 1817050606 134S1641E 80