Tropical Cyclones
[Index] | Tropical Cyclone ZENA : JTWC Advisories |
Season 2015-2016 Summaries (Operational Data): [AU] [SIO] [SPAC] [SH] | |
---> Tropical Cyclone ZENA Track Map and Data |
WTPS22 PGTW 20160404 21:30z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 140 NM EITHER SIDE OF A LINE FROM 13.6S 162.7E TO 17.2S 171.2E WITHIN THE NEXT 06 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT IMAGERY AT 041800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 13.8S 163.1E. THE SYSTEM IS MOVING EAST-SOUTHEASTWARD AT 08 KNOTS. 2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 12.9S 161.6E IS NOW LOCATED NEAR 13.8S 163.1E, APPROXIMATELY 385 NM NORTHWEST OF PORT VILA, VANUATU. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS FORMATIVE, DEEP CONVECTIVE BANDING WRAPPING INTO THE SYSTEM. A 041714Z SSMIS 91 GHZ IMAGE REVEALS TIGHTLY CURVED CONVECTIVE BANDING WRAPPING INTO A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW-MODERATE (10 TO 20 KNOTS) VERTICAL WIND SHEAR (VWS) AND RADIAL OUTFLOW. DYNAMIC MODEL GUIDANCE IS IN FAIR AGREEMENT ON 97P TRACKING SOUTHEASTWARD, AND STEERED BY A NEAR EQUATORIAL RIDGE TO THE NORTH. THIS SYSTEM HAS A SHORT WINDOW FOR INTENSIFICATION OVER THE NEXT 36 TO 48 HOURS UNDER A FAVORABLE UPPER- LEVEL ENVIRONMENT. AFTER TAU 48, 97P WILL BEGIN TO WEAKEN AS IT ENCOUNTERS UNFAVORABLE VWS ASSOCIATED WITH AN APPROACHING TROUGH. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED TO BE NEAR 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 MB. THE POTENTIAL FOR DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH. 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 052130Z.// ========================================================================= WTPS31 PGTW 20160405 09:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18P (EIGHTEEN) WARNING NR 001// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/042121ZAPR2016// AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.// RMKS/ 1. TROPICAL CYCLONE 18P (EIGHTEEN) WARNING NR 001 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 14.8S 166.4E MOVEMENT PAST SIX HOURS - 110 DEGREES AT 18 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY REPEAT POSIT: 14.8S 166.4E --- FORECASTS: 12 HRS, VALID AT: 051800Z --- 16.6S 170.1E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 110 DEG/ 22 KTS --- 24 HRS, VALID AT: 060600Z --- 18.1S 174.4E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 075 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 105 DEG/ 23 KTS --- 36 HRS, VALID AT: 061800Z --- 19.2S 179.1E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 095 DEG/ 20 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 070600Z --- 19.6S 176.6W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 050900Z POSITION NEAR 15.3S 167.3E. TROPICAL CYCLONE (TC) 18P (EIGHTEEN), LOCATED APPROXIMATELY 718 NM WEST-NORTHWEST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 18 KNOTS OVER THE PAST SIX HOURS. CURRENTLY THE SYSTEM IS TRACKING OVER THE NORTHERN SECTION OF THE ISLAND OF ESPIRITU SANTO. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER WITH IMPROVED DEEP CONVECTIVE BANDING. A 050700Z SSMIS 91GHZ IMAGE SHOWS A COMPACT CONVECTIVE CORE WITH DEEP CONVECTIVE BANDING WRAPPING TIGHTLY AROUND A WELL-DEFINED CENTER. SURFACE OBSERVATIONS FROM NVSS (91554) INDICATE EASTERLY SUSTAINED WINDS OF 21 KNOTS WITH SLP NEAR 998MB (HOWEVER, THIS SITE IS LOCATED ON THE SOUTHEAST CORNER OF ESPIRITU SANTO THUS LIKELY SHIELDED BY THE 5000 TO 6000 FOOT NORTH-SOUTH ORIENTED MOUNTAIN RANGE ALONG THE WEST COAST). THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS BASED ON DVORAK ESTIMATES OF 35 KNOTS FROM ALL AGENCIES. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW-MODERATE (10 TO 20 KNOTS) VERTICAL WIND SHEAR (VWS) AND RADIAL OUTFLOW. TC 18P IS FORECAST TO TRACK EAST-SOUTHEASTWARD TO EASTWARD THROUGH THE FORECAST PERIOD AS IT TRACKS WITHIN ENHANCED FLOW BETWEEN THE SUBTROPICAL RIDGE AND A BROAD SHORTWAVE TROUGH. DYNAMIC GUIDANCE IS IN TIGHT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. TC 18P IS FORECAST TO INTENSIFY THROUGH TAU 24 UNDER FAVORABLE CONDITIONS. AFTER TAU 24, INCREASING VERTICAL WIND SHEAR ASSOCIATED WITH THE SUBTROPICAL WESTERLIES WILL SERVE TO RAPIDLY WEAKEN THE SYSTEM LEADING TO DISSIPATION BY TAU 48. AFTER TAU 48, THE REMNANTS ARE EXPECTED TO BECOME QUASI-STATIONARY IN THE FIJI REGION AS A LOW- LEVEL HIGH BUILDS IN. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 050600Z IS 12 FEET. NEXT WARNINGS AT 052100Z AND 060900Z. THIS CANCELS AND SUPERSEDES REF A (WTPS22 PGTW 042130).// ========================================================================= WTPS31 PGTW 20160405 21:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18P (ZENA) WARNING// RMKS/ 1. TROPICAL CYCLONE 18P (ZENA) WARNING NR 002 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 051800Z --- NEAR 16.6S 170.3E MOVEMENT PAST SIX HOURS - 115 DEGREES AT 23 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT REPEAT POSIT: 16.6S 170.3E --- FORECASTS: 12 HRS, VALID AT: 060600Z --- 18.3S 174.5E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 010 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 105 DEG/ 23 KTS --- 24 HRS, VALID AT: 061800Z --- 19.5S 179.2E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 100 DEG/ 25 KTS --- 36 HRS, VALID AT: 070600Z --- 20.4S 175.6W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 095 DEG/ 21 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 071800Z --- 20.7S 171.1W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 052100Z POSITION NEAR 17.0S 171.3E. TROPICAL CYCLONE (TC) 18P (ZENA), LOCATED APPROXIMATELY 472 NM WEST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 23 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS A TIGHT LOW-LEVEL CIRCULATION CENTER SURROUNDED BY DEEP CONVECTIVE BANDING. A 051701Z SSMIS 91GHZ IMAGE SHOWS A VERY COMPACT CONVECTIVE CORE WITH A WELL-DEFINED MICROWAVE EYE FEATURE. THE INITIAL INTENSITY IS ASSESSED AT 65 KNOTS BASED ON DVORAK ESTIMATES OF T4.0 FROM ALL AGENCIES. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW-MODERATE (10 TO 20 KNOTS)VERTICAL WIND SHEAR (VWS) WITH GOOD POLEWARD OUTFLOW. TC 18P IS FORECAST TO TRACK EAST-SOUTHEASTWARD TO EASTWARD THROUGH THE FORECAST PERIOD AS IT TRACKS WITHIN ENHANCED FLOW BETWEEN THE SUBTROPICAL RIDGE AND A BROAD SHORTWAVE TROUGH. DYNAMIC GUIDANCE IS IN TIGHT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. TC 18P IS FORECAST TO INTENSIFY SLIGHTLY THROUGH TAU 12 UNDER FAVORABLE CONDITIONS. AFTER TAU 12, INCREASING VWS ASSOCIATED WITH THE SUBTROPICAL WESTERLIES WILL SERVE TO RAPIDLY WEAKEN THE SYSTEM LEADING TO DISSIPATION BY TAU 48. AFTER TAU 48, THE REMNANTS OF TC 18P ARE EXPECTED TO BECOME QUASI-STATIONARY EAST OF FIJI, AS A LOW-LEVEL RIDGE BUILDS IN. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051800Z IS 18 FEET. NEXT WARNINGS AT 060300Z, 060900Z, 061500Z AND 062100Z.// ========================================================================= WTPS31 PGTW 20160406 03:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18P (ZENA) WARNING NR 003// RMKS/ 1. TROPICAL CYCLONE 18P (ZENA) WARNING NR 003 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 060000Z --- NEAR 17.7S 172.8E MOVEMENT PAST SIX HOURS - 115 DEGREES AT 26 KTS POSITION ACCURATE TO WITHIN 015 NM POSITION BASED ON EYE FIXED 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 - 015 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT REPEAT POSIT: 17.7S 172.8E --- FORECASTS: 12 HRS, VALID AT: 061200Z --- 19.3S 177.4E MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 105 DEG/ 23 KTS --- 24 HRS, VALID AT: 070000Z --- 20.4S 177.8W MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 100 DEG/ 21 KTS --- 36 HRS, VALID AT: 071200Z --- 21.0S 173.3W MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 095 DEG/ 20 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 080000Z --- 21.2S 169.1W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL --- REMARKS: 060300Z POSITION NEAR 18.1S 173.9E. TROPICAL CYCLONE (TC) 18P (ZENA), LOCATED APPROXIMATELY 321 NM WEST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 26 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY REVEALS A 5 NM WIDE PINHOLE EYE FEATURE WITH PERSISTENT, DEEP CONVECTION AROUND THE SYSTEM, WHICH SUPPORTS THE CURRENT BEST TRACK POSITION WITH HIGH CONFIDENCE. A 052214Z AMSU 89 GHZ IMAGE DEPICTS TIGHTLY CURVED CONVECTIVE BANDING WRAPPING INTO A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER. THE CURRENT INTENSITY IS ASSESSED AT 90 KNOTS AND IS SUPPORTED BY AGENCY DVORAK VALUES OF T5.0 FROM PGTW AND KNES. THE UPPER LEVEL ENVIRONMENT REMAINS FAVORABLE WITH DUAL CHANNEL OUTFLOW AND MODERATE (15 TO 25 KNOTS) VERTICAL WIND SHEAR (VWS). TC ZENA IS TRACKING WITHIN ENHANCED FLOW BETWEEN THE SUBTROPICAL RIDGE AND A BROAD SHORTWAVE TROUGH. THIS SYSTEM IS FORECAST TO CONTINUE TRACKING EAST-SOUTHEASTWARD AND THEN EASTWARD WITHIN THIS ENHANCED WESTERLY FLOW THROUGHOUT THE FORECAST PERIOD. TC 18P WILL WEAKEN RAPIDLY OVER THE NEXT 48 HOURS AS VWS BECOMES UNFAVORABLE. THE SYSTEM IS FORECAST TO BEGIN SUBTROPICAL TRANSITION AT TAU 36 AND COMPLETE SUBTROPICAL TRANSITION BY TAU 48, AS IT BECOMES FULLY EMBEDDED WITHIN THE SUBTROPICAL TROUGH. DYNAMIC MODEL GUIDANCE IS IN EXCELLENT AGREEMENT ON THE TRACK OF TC ZENA, LENDING TO HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 060000Z IS 22 FEET. NEXT WARNINGS AT 060900Z, 061500Z, 062100Z AND 070300Z.// ========================================================================= WTPS31 PGTW 20160406 09:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18P (ZENA) WARNING NR 004// RMKS/ 1. TROPICAL CYCLONE 18P (ZENA) WARNING NR 004 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 18.5S 175.1E MOVEMENT PAST SIX HOURS - 110 DEGREES AT 23 KTS POSITION ACCURATE TO WITHIN 060 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 - 015 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 18.5S 175.1E --- FORECASTS: 12 HRS, VALID AT: 061800Z --- 19.7S 179.8E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 105 DEG/ 25 KTS --- 24 HRS, VALID AT: 070600Z --- 20.9S 175.1W MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 100 DEG/ 24 KTS --- 36 HRS, VALID AT: 071800Z --- 21.7S 170.0W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 105 DEG/ 25 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 080600Z --- 23.0S 164.7W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL --- REMARKS: 060900Z POSITION NEAR 18.8S 176.3E. TROPICAL CYCLONE (TC) 18P (ZENA), LOCATED APPROXIMATELY 190 NM WEST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 23 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY INDICATES A GENERAL WEAKENING TREND WITH DECAYING CORE CONVECTION AND THE LOSS OF THE VISIBLE EYE FEATURE, THEREFORE, DVORAK INTENSITY ESTIMATES HAVE DECREASED TO 4.5 (77 KNOTS). CONSEQUENTLY, THE INITIAL INTENSITY IS NOW ASSESSED AT 80 KNOTS. UPPER-LEVEL ANALYSIS INDICATES INCREASING WESTERLY VERTICAL WIND SHEAR (VWS) AT MODERATE TO STRONG LEVELS (20 TO 30 KNOTS), HOWEVER, OUTFLOW HAS REMAINED ROBUST. TC 18P IS TRACKING QUICKLY EAST-SOUTHEASTWARD UNDER ENHANCED FLOW BETWEEN THE SUBTROPICAL RIDGE AND A BROAD TROUGH, AND IS FORECAST TO CONTINUE TRACKING EAST-SOUTHEASTWARD THROUGH THE FORECAST PERIOD. TC 18P IS FORECAST TO WEAKEN THROUGH THE FORECAST PERIOD AS IT ENCOUNTERS INCREASING VWS ASSOCIATED WITH SUBTROPICAL WESTERLY FLOW. THE SYSTEM IS FORECAST TO TRANSITION TO A SUBTROPICAL LOW BY TAU 48, HOWEVER, TC 18P MAY WEAKEN BELOW 35 KNOTS AFTER TAU 36. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT OVERALL, THEREFORE THERE IS HIGH CONFIDENCE IN THE OFFICIAL FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 060600Z IS 22 FEET. NEXT WARNINGS AT 061500Z, 062100Z, 070300Z AND 070900Z.// ========================================================================= WTPS31 PGTW 20160406 15:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18P (ZENA) WARNING NR 005// RMKS/ 1. TROPICAL CYCLONE 18P (ZENA) WARNING NR 005 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 061200Z --- NEAR 19.4S 177.4E MOVEMENT PAST SIX HOURS - 115 DEGREES AT 24 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT REPEAT POSIT: 19.4S 177.4E --- FORECASTS: 12 HRS, VALID AT: 070000Z --- 20.5S 177.7W MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 105 DEG/ 24 KTS --- 24 HRS, VALID AT: 071200Z --- 21.5S 172.6W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL VECTOR TO 36 HR POSIT: 105 DEG/ 25 KTS --- 36 HRS, VALID AT: 080000Z --- 22.6S 167.4W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL --- REMARKS: 061500Z POSITION NEAR 19.7S 178.6E. TROPICAL CYCLONE (TC) 18P (ZENA), LOCATED APPROXIMATELY 96 NM SOUTHWEST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 24 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES A RAPIDLY WEAKENING SYSTEM WITH DECAYING DEEP CONVECTION SHEARED EAST OF THE CENTER. DVORAK INTENSITY ESTIMATES HAVE DECREASED TO 4.0 (65 KNOTS) AND THE INITIAL INTENSITY IS NOW ASSESSED AT 65 KNOTS. UPPER-LEVEL ANALYSIS INDICATES INCREASING WESTERLY VERTICAL WIND SHEAR (VWS) AT STRONG LEVELS (30 TO 40 KNOTS) PARTIALLY OFFSET BY ROBUST POLEWARD OUTFLOW. TC 18P IS TRACKING QUICKLY EAST-SOUTHEASTWARD UNDER ENHANCED FLOW BETWEEN THE SUBTROPICAL RIDGE AND A BROAD TROUGH, AND IS FORECAST TO CONTINUE TRACKING EAST-SOUTHEASTWARD THROUGH THE FORECAST PERIOD. TC 18P IS FORECAST TO WEAKEN THROUGH THE FORECAST PERIOD AS IT ENCOUNTERS INCREASING VWS ASSOCIATED WITH SUBTROPICAL WESTERLY FLOW. THE SYSTEM IS FORECAST TO TRANSITION TO A SUBTROPICAL LOW BY TAU 36, HOWEVER, TC 18P MAY WEAKEN BELOW 35 KNOTS AFTER TAU 24. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT OVERALL, THEREFORE THERE IS HIGH CONFIDENCE IN THE OFFICIAL FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 061200Z IS 20 FEET. NEXT WARNINGS AT 062100Z, 070300Z, 070900Z AND 071500Z.// ========================================================================= WTPS31 PGTW 20160406 21:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18P (ZENA) WARNING NR 006// RMKS/ 1. TROPICAL CYCLONE 18P (ZENA) WARNING NR 006 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 061800Z --- NEAR 20.5S 178.7W MOVEMENT PAST SIX HOURS - 105 DEGREES AT 31 KTS POSITION ACCURATE TO WITHIN 060 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 - 025 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT REPEAT POSIT: 20.5S 178.7W --- FORECASTS: 12 HRS, VALID AT: 070600Z --- 21.7S 172.9W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 100 DEG/ 28 KTS --- 24 HRS, VALID AT: 071800Z --- 22.7S 166.9W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 062100Z POSITION NEAR 20.8S 177.2W. TROPICAL CYCLONE 18P (ZENA), LOCATED APPROXIMATELY 218 NM SOUTHEAST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 31 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES THAT TC ZENA (18P) CONTINUES TO RAPIDLY WEAKEN. A 1759Z 91GHZ MICROWAVE IMAGE SHOWS THAT THE DEEP CONVECTION IS SHEARED EAST OF A WEAK LOW LEVEL CIRCULATION CENTER (LLCC) WITH NO CONVECTIVE BANDING EVIDENT. INITIAL INTENSITY IS ASSESSED AT 55 KNOTS BASED ON DVORAK DT ESTIMATES OF 3.5 FROM BOTH PGTW AND KNES. UPPER-LEVEL ANALYSIS INDICATES TC ZENA IS CURRENTLY IN AN AREA OF HIGH (40-50 KNOTS) NORTHWESTERLY ENVIRONMENTAL VERTICAL WIND SHEAR (VWS). HOWEVER, AS THE STORM MOTION VECTOR IS ALIGNED WITH THE SHEAR VECTOR, THE EFFECTIVE SHEAR VALUE IS LOWER AT AROUND 20-25 KNOTS. THE LOWER EFFECTIVE VWS VALUE IS ALLOWING TC ZENA TO MAINTAIN INTENSITY FOR LONGER THAN WOULD OTHERWISE BE EXPECTED IN SUCH AN ENVIRONMENT. TC ZENA IS TRACKING RAPIDLY EAST-SOUTHEASTWARD UNDER THE ENHANCED FLOW BETWEEN THE SUBTROPICAL RIDGE (STR) TO THE NORTH AND A BROAD TROUGH TO THE SOUTHWEST AND IS FORECAST TO CONTINUE THIS TRACK MOTION THROUGH THE FORECAST PERIOD. THE SYSTEM WILL CONTINUE TO WEAKEN AS IT ENCOUNTERS STEADILY INCREASING VWS ASSOCIATED WITH MID-LATITUDE WESTERLY FLOW AND WILL DISSIPATE OVER WATER BY TAU 24. WHILE DISSIPATING, TC ZENA WILL SIMULTANEOUSLY UNDERGO TRANSITION TO A SUBTROPICAL LOW BUT WILL COMPLETE DISSIPATION FIRST, BEFORE COMPLETING SUBTROPICAL TRANSITION. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT OVERALL, THEREFORE THERE IS HIGH CONFIDENCE IN THE OFFICIAL FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 061800Z IS 18 FEET. NEXT WARNINGS AT 070300Z, 070900Z AND 071500Z.// ========================================================================= WTPS31 PGTW 20160407 03:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE WARNING// RMKS/ 1. TROPICAL CYCLONE 18P (ZENA) 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: 070000Z --- NEAR 21.5S 176.0W MOVEMENT PAST SIX HOURS - 110 DEGREES AT 27 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT REPEAT POSIT: 21.5S 176.0W --- FORECASTS: 12 HRS, VALID AT: 071200Z --- 22.2S 170.7W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 100 DEG/ 20 KTS --- 24 HRS, VALID AT: 080000Z --- 22.7S 166.3W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 070300Z POSITION NEAR 21.7S 174.7W. TROPICAL CYCLONE (TC) 18P (ZENA), LOCATED APPROXIMATELY 56 NM WEST- SOUTHWEST OF TONGA, HAS TRACKED EAST-SOUTHEASTWARD AT 27 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A DETERIORATING CONVECTIVE STRUCTURE PARTIALLY OBSCURING A POORLY DEFINED LOW LEVEL CIRCULATION CENTER (LLCC) WHICH LEADS TO LOW CONFIDENCE IN THE CURRENT POSITION. THE INITIAL INTENSITY HAS BEEN LOWERED TO 50 KNOTS BASED ON DECREASING DVORAK INTENSITY ESTIMATES FROM ALL AGENCIES AND SUPPORTS THE CURRENT STATE OF THE CYCLONE. THE SYSTEM IS TRACKING IN A POOR ENVIRONMENT WITH 40 TO 50 KNOT NORTHWESTERLY VERTICAL WIND SHEAR (VWS) EASILY OFFSETTING THE STRONG POLEWARD OUTFLOW INTO THE MID-LATITUDE WESTERLIES. HOWEVER, THE SYSTEM IS MOVING IN-PHASE WITH THE VWS KEEPING THE LLCC PARTIALLY UNDER THE CONVECTION. TC ZENA IS TRACKING RAPIDLY SOUTHEASTWARD UNDER THE INFLUENCE OF THE COMBINED EFFECTS OF A SUB- TROPICAL RIDGE TO THE NORTHEAST AND A MID-LATITUDE TROUGH TO THE WEST. TC 18P WILL CONTINUE ON THIS COURSE AND FULLY DISSIPATE OVER THE NEXT 24 HOURS DUE TO THE EFFECTS OF THE HIGH VWS. DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT, LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070000Z IS 15 FEET. NEXT WARNINGS AT 070900Z, 071500Z AND 072100Z.// ========================================================================= WTPS31 PGTW 20160407 09:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18P (ZENA) WARNING NR 008// RMKS/ 1. TROPICAL CYCLONE 18P (ZENA) WARNING NR 008 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 070600Z --- NEAR 22.1S 173.4W MOVEMENT PAST SIX HOURS - 105 DEGREES AT 25 KTS POSITION ACCURATE TO WITHIN 025 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER REPEAT POSIT: 22.1S 173.4W --- FORECASTS: 12 HRS, VALID AT: 071800Z --- 22.7S 168.3W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 070900Z POSITION NEAR 22.3S 172.1W. TROPICAL CYCLONE (TC) 18P (ZENA), LOCATED APPROXIMATELY 108 NM EAST- SOUTHEAST OF TONGA, HAS TRACKED EAST-SOUTHEASTWARD AT 25 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE MAIN CONVECTION HAS SIGNIFICANTLY ERODED AND HAS DECOUPLED FROM AN UNRAVELING LOW LEVEL CIRCULATION. THE INITIAL POSITION IS EXTRAPOLATED FROM A 070341Z SSMI-S MICROWAVE PASS WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN OVERALL ASSESSMENT OF SUBJECTIVE AND OBJECTIVE DVORAK ESTIMATES AND IS SUPPORTED BY A 070206Z RAPIDSCAT PASS. ENVIRONMENTAL ANALYSIS INDICATES THE SYSTEM HAS DRIFTED INTO AN AREA OF STRONG (30-40 KNOT) VERTICAL WIND SHEAR AND COOLER SEA SURFACE TEMPERATURES (26 CELSIUS). THESE CONDITIONS ARE EXPECTED TO WORSEN AND CAUSE FURTHER DECAY TO TC 18P. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070600Z IS 12 FEET.
Tropical cyclone tracks developed by Michael Bath using operational warnings and advisories.
Document: tropical_cyclone_zena_jtwc_advisories.htm
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