WTPS51 PGTW 050900 WARNING ATCG MIL 18P SWP 170505065608 2017050506 18P DONNA 007 01 230 08 SATL 060 T000 136S 1656E 090 R064 025 NE QD 035 SE QD 035 SW QD 020 NW QD R050 040 NE QD 055 SE QD 050 SW QD 040 NW QD R034 080 NE QD 120 SE QD 115 SW QD 090 NW QD T012 140S 1649E 095 R064 030 NE QD 035 SE QD 035 SW QD 030 NW QD R050 050 NE QD 060 SE QD 060 SW QD 045 NW QD R034 105 NE QD 140 SE QD 135 SW QD 095 NW QD T024 144S 1646E 100 R064 035 NE QD 035 SE QD 035 SW QD 030 NW QD R050 050 NE QD 065 SE QD 065 SW QD 050 NW QD R034 115 NE QD 160 SE QD 160 SW QD 105 NW QD T036 149S 1645E 105 R064 040 NE QD 035 SE QD 040 SW QD 035 NW QD R050 055 NE QD 070 SE QD 065 SW QD 055 NW QD R034 120 NE QD 160 SE QD 160 SW QD 105 NW QD T048 157S 1645E 115 R064 040 NE QD 040 SE QD 040 SW QD 035 NW QD R050 060 NE QD 070 SE QD 065 SW QD 060 NW QD R034 135 NE QD 160 SE QD 160 SW QD 120 NW QD T072 179S 1651E 115 R064 040 NE QD 040 SE QD 040 SW QD 035 NW QD R050 065 NE QD 070 SE QD 070 SW QD 055 NW QD R034 145 NE QD 160 SE QD 150 SW QD 120 NW QD T096 199S 1667E 080 R064 040 NE QD 040 SE QD 040 SW QD 035 NW QD R050 065 NE QD 070 SE QD 070 SW QD 055 NW QD R034 135 NE QD 145 SE QD 130 SW QD 120 NW QD T120 217S 1690E 040 R034 125 NE QD 120 SE QD 110 SW QD 110 NW QD AMP 120HR BECOMING EXTRATROPICAL SUBJ: TROPICAL CYCLONE 18P (DONNA) WARNING NR 007 1. TROPICAL CYCLONE 18P (DONNA) WARNING NR 007 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 050600Z --- NEAR 13.6S 165.6E MOVEMENT PAST SIX HOURS - 230 DEGREES AT 08 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 115 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT REPEAT POSIT: 13.6S 165.6E --- FORECASTS: 12 HRS, VALID AT: 051800Z --- 14.0S 164.9E MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 135 NM SOUTHWEST QUADRANT 095 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 215 DEG/ 02 KTS --- 24 HRS, VALID AT: 060600Z --- 14.4S 164.6E MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 115 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 105 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 190 DEG/ 03 KTS --- 36 HRS, VALID AT: 061800Z --- 14.9S 164.5E MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 105 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 180 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 070600Z --- 15.7S 164.5E MAX SUSTAINED WINDS - 115 KT, GUSTS 140 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 165 DEG/ 06 KTS --- 72 HRS, VALID AT: 080600Z --- 17.9S 165.1E MAX SUSTAINED WINDS - 115 KT, GUSTS 140 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 150 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 145 DEG/ 06 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 090600Z --- 19.9S 166.7E MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT 145 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 130 DEG/ 07 KTS --- 120 HRS, VALID AT: 100600Z --- 21.7S 169.0E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT --- REMARKS: 050900Z POSITION NEAR 13.7S 165.4E. TROPICAL CYCLONE (TC) 18P (DONNA), LOCATED APPROXIMATELY 291 NM NORTH-NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED SOUTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS CONTINUED TO DEEPEN AS SPIRAL BANDS CURVED TIGHTER INTO THE CENTER. THE INITIAL POSITION IS BASED ON A DIMPLE FEATURE IN THE MSI LOOP THAT LINES UP WELL WITH A LOW REFLECTIVITY CIRCULATION FEATURE IN THE 050409Z SSMI MICROWAVE PASS. THE INITIAL INTENSITY IS BASED ON AN OVERALL ASSESSMENT OF AGENCY AND OBJECTIVE DVORAK ESTIMATES AND REFLECTS THE DEEPENED STATE OF THE CYCLONE. ENVIRONMENTAL ANALYSIS INDICATES A VERY FAVORABLE ENVIRONMENT WITH WARM SSTS NEAR 30 CELSIUS AND EXCELLENT RADIAL OUTFLOW ALOFT. THERE IS LIGHT TO MODERATE ALONG-TRACK VERTICAL WIND SHEAR (VWS) BUT IS MOSTLY OFFSET BY THE OUTFLOW AND THE STORM MOTION THAT IS IN-PHASE WITH THE UPPER LEVEL WIND FLOW. TC DONNA IS TRACKING ALONG THE NORTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE SOUTH. AFTER TAU 24, A MID-LATITUDE TROUGH APPROACHING FROM THE SOUTHWEST IS EXPECTED TO WEAKEN THE STR AND CAUSE THE CYCLONE TO TRACK POLEWARD THEN ACCELERATE SOUTHEASTWARD. AS FAVORABLE CONDITIONS PERSIST IN THE NEAR- TO MID-TERM, THE SYSTEM WILL CONTINUE TO INTENSIFY, PEAKING AT 115 KNOTS BETWEEN TAU 36-48. AFTERWARD, INCREASING VWS AND COOLING SSTS WILL GRADUALLY WEAKEN THE CYCLONE. BY TAU 120, TC DONNA WILL BEGIN EXTRA-TROPICAL TRANSITION. NUMERICAL MODEL GUIDANCE IS IN OVERALL AGREEMENT WITH EGRR AS THE SOLE EASTWARD OUTLIER. THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 050600Z IS 30 FEET. NEXT WARNINGS AT 052100Z AND 060900Z.// 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 131S1662E 85 1817050500 131S1662E 85 1817050500 131S1662E 85 1817050506 136S1656E 90 1817050506 136S1656E 90 1817050506 136S1656E 90 NNNN