Tropical Cyclones
[Index] | Tropical Cyclone ZUMAN : JTWC Advisories |
Season 1997-1998 Summaries (Operational Data): [AU] [SIO] [SPAC] [SH] | |
---> Tropical Cyclone ZUMAN Track Map and Data |
WTPS21 PGTW 980329 13:30z SUBJ/TROPICAL CYCLONE FORMATION ALERT 291321Z MAR 98// RMKS/ 1. IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA 2. IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY AND AMEMBASSY HONIARA SOLOMON ISLANDS 3. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN A 240 NM RADIUS OF 13.6S0 171.6E5 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 20 TO 30 KNOTS. METSAT IMAGERY AT 291130Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 13.7S1 171.8E7. THE SYSTEM IS MOVING SOUTH-SOUTHEASTWARD AT 02 KNOTS. 4. REMARKS: THE TROPICAL DISTURBANCE NORTHWEST OF FIJI CONTINUES TO BECOME BETTER ORGANIZED. ANIMATED WATER VAPOR IMAGERY INDICATE THAT A UPPER LEVEL ANTICYCLONE HAS DEVELOPED OVER THE DISTURBANCE. ANIMATED INFRARED SATELLITE IMAGERY INDICATE THAT CONVECTION HAS PERSISTED OVER THE SYSTEM CENTER WITH SOME INDICATION OF CYCLONIC TURNING. THE POTENTIAL FOR SIGNIFICANT TROPICAL CYCLONE DEVELOPMENT WITHIN THE NEXT 24 HOURS IS GOOD. 5. THIS ALERT VALID UNTIL 301330Z0.// ========================================================================= WTPS31 PGTW 980330 03:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P WARNING NR 001 02 ACTIVE TROPICAL CYCLONES IN SOUTHWEST PACIFIC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 300000Z3 --- 14.5S0 171.0E9 MOVEMENT PAST SIX HOURS - 210 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 040 KT RADIUS OF 035 KT WINDS - 045 NM REPEAT POSIT: 14.5S0 171.0E9 --- FORECASTS: 12 HRS, VALID AT: 301200Z6 --- 14.9S4 170.2E0 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 065 NM VECTOR TO 24 HR POSIT: 260 DEG/ 03 KTS --- 24 HRS, VALID AT: 310000Z4 --- 15.0S6 169.6E2 MAX SUSTAINED WINDS - 050 KT, GUSTS 060 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 075 NM VECTOR TO 36 HR POSIT: 270 DEG/ 03 KTS --- 36 HRS, VALID AT: 311200Z7 --- 15.0S6 168.9E4 MAX SUSTAINED WINDS - 055 KT, GUSTS 065 KT RADIUS OF 050 KT WINDS - 030 NM RADIUS OF 035 KT WINDS - 085 NM VECTOR TO 48 HR POSIT: 270 DEG/ 03 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 010000Z1 --- 15.0S6 168.2E7 MAX SUSTAINED WINDS - 065 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 050 NM RADIUS OF 035 KT WINDS - 115 NM OVER WATER --- REMARKS: 300300Z6 POSITION 14.6S1 170.8E6. DURING THE PAST 12 HOURS, THE SYSTEM WEST OF FIJI HAS UNDERGONE SIGNIFICANT DEVELOPMENT AND IS NOW CONSIDERED A TROPICAL CYCLONE. TROPICAL CYCLONE 31P HAS BEEN TRACKING TOWARDS THE SOUTHWEST AT 06 KNOTS FOR THE PAST 6 HOURS UNDER THE INFLUENCE OF A RIDGE OF HIGH PRESSURE TO THE SOUTH. THE WARNING POSITION IS BASED ON 292330Z9 VISIBLE SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON A 292330Z9 SATELLITE DVORAK INTENSITY ESTIMATE OF 35 KNOTS. THE SYSTEM IS IN AN AREA OF WARM SEA SURFACE TEMPERATURES AND WEAKENING VERTICAL WIND SHEAR WHICH SHOULD ALLOW IT TO CONTINUE DEVELOPING THROUGHOUT THE FORECAST PERIOD. THE RIDGE OF HIGH PRESSURE TO THE SOUTH IS EXPECTED TO STEER TROPICAL CYCLONE 31P TOWARDS THE WEST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 300000Z3 IS 13 FEET. NEXT WARNINGS AT 301500Z9 (DTG 301351Z3) AND 310300Z7 (DTG 310151Z1). REFER TO TROPICAL CYCLONE 30P (NATHAN) WARNINGS (WTPS32 PGTW) FOR SIX-HOURLY UPDATES.// ========================================================================= WTPS31 PGTW 980330 15:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P WARNING NR 002 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 301200Z6 --- 14.3S8 169.7E3 MOVEMENT PAST SIX HOURS - 270 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 045 NM REPEAT POSIT: 14.3S8 169.7E3 --- FORECASTS: 12 HRS, VALID AT: 310000Z4 --- 14.3S8 168.4E9 MAX SUSTAINED WINDS - 060 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 020 NM SOUTH SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 065 NM SOUTH SEMICIRCLE 055 NM ELSEWHERE VECTOR TO 24 HR POSIT: 265 DEG/ 08 KTS --- 24 HRS, VALID AT: 311200Z7 --- 14.5S0 166.7E0 MAX SUSTAINED WINDS - 070 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 025 NM SOUTH SEMICIRCLE 010 NM ELSEWHERE RADIUS OF 035 KT WINDS - 075 NM SOUTH SEMICIRCLE 065 NM ELSEWHERE VECTOR TO 36 HR POSIT: 260 DEG/ 10 KTS --- 36 HRS, VALID AT: 010000Z1 --- 14.9S4 164.6E7 MAX SUSTAINED WINDS - 080 KT, GUSTS 095 KT RADIUS OF 050 KT WINDS - 030 NM SOUTH SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 085 NM SOUTH SEMICIRCLE 070 NM ELSEWHERE VECTOR TO 48 HR POSIT: 250 DEG/ 08 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 011200Z4 --- 15.4S0 163.1E1 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 100 NM SOUTHEAST SEMICIRCLE 085 NM ELSEWHERE --- REMARKS: 301500Z9 POSITION 14.3S8 169.4E0. TROPICAL CYCLONE 31P CONTINUES TO STRENGTHEN AS IT TRACKS WESTWARD AT 06 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED UPON 301130Z8 ENHANCED INFRARED SATELLITE IMAGERY AND THE WARNING INTENSITY IS BASED ON A SATELLITE INTENSITY ESTIMATE OF 45 KNOTS. THE SYSTEM SHOULD CONTINUE TO TRACK IN A GENERALLY WESTWARD DIRECTION THROUGH THE NEXT 36 HOURS DUE TO STEERING FROM MID LEVEL HIGH PRESSURE LOCATED TO THE SOUTH. THE SYSTEM WILL BEGIN TO TRACK MORE WEST- SOUTHWESTWARD AT THE 48 HOUR POSITION AS A MID LATITUDE TROUGH APPROACHES FROM THE WEST. THE SYSTEM SHOULD INTENSIFY THROUGH THE PERIOD AS VERTICAL WIND SHEAR WILL REMAIN LOW AND SEA SURFACE TEMPERATURES ARE WARM. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 301200Z IS 14 FEET. NEXT WARNINGS AT 310300Z7 (DTG 310153Z3) AND 311500Z0 (DTG 311353Z6). REFER TO TROPICAL CYCLONE 30P (NATHAN) WARNINGS (WTPS32 PGTW) FOR SIX-HOURLY UPDATES.// ========================================================================= WTPS31 PGTW 980331 03:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 003 02 ACTIVE TROPICAL CYCLONES IN SOUTHWEST PACIFIC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 310000Z4 --- 14.0S5 168.4E9 MOVEMENT PAST SIX HOURS - 270 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 035 NM RADIUS OF 035 KT WINDS - 085 NM NORTH SEMICIRCLE 100 NM ELSEWHERE REPEAT POSIT: 14.0S5 168.4E9 --- FORECASTS: 12 HRS, VALID AT: 311200Z7 --- 14.1S6 167.1E5 MAX SUSTAINED WINDS - 070 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 035 NM SOUTH SEMICIRCLE 025 NM ELSEWHERE RADIUS OF 035 KT WINDS - 105 NM SOUTH SEMICIRCLE OVER WATER 085 NM ELSEWHERE VECTOR TO 24 HR POSIT: 255 DEG/ 08 KTS --- 24 HRS, VALID AT: 010000Z1 --- 14.5S0 165.4E6 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 035 NM SOUTH SEMICIRCLE 025 NM ELSEWHERE RADIUS OF 035 KT WINDS - 110 NM SOUTH SEMICIRCLE OVER WATER 090 NM ELSEWHERE VECTOR TO 36 HR POSIT: 245 DEG/ 10 KTS --- 36 HRS, VALID AT: 011200Z4 --- 15.3S9 163.4E4 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 115 NM SOUTHEAST SEMICIRCLE 095 NM ELSEWHERE VECTOR TO 48 HR POSIT: 240 DEG/ 11 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 020000Z2 --- 16.4S1 161.5E3 MAX SUSTAINED WINDS - 100 KT, GUSTS 120 KT RADIUS OF 050 KT WINDS - 045 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 120 NM SOUTHEAST SEMICIRCLE 100 NM ELSEWHERE --- REMARKS: 310300Z7 POSITION 14.0S5 168.1E6. TROPICAL CYCLONE 31P (ZUMAN) IS TRACKING WESTWARD AT 06 KNOTS. THE WARNING POSITION IS BASED ON 302330Z1 VISIBLE SATELLITE IMAGERY AND 301949Z6 MICROWAVE IMAGERY. THE WARNING INTENSITY OF 65 KNOTS IS BASED ON A SATELLITE-DERIVED DVORAK CURRENT INTENSITY ESTIMATE OF CI4.0. THE SYSTEM IS EXPECTED TO CONTINUE TRACKING WESTWARD FOR THE NEXT 12 HOURS UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE TO THE SOUTH. AN APPROACHING TROUGH WILL CAUSE THE SYSTEM TO GAIN LATITUDE AFTER THIS. TROPICAL CYCLONE 31P (ZUMAN) IS FORECAST TO CONTINUE TO INTENSIFY THROUGHOUT THE FORECAST AS THE SYSTEM IS IN A FAVORABLE ENVIRONMENT AND HAS EXCELLENT OUTFLOW IN ALL QUADRANTS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 310000Z IS 18 FEET. NEXT WARNINGS AT 311500Z0 (DTG 311353Z6) AND 010300Z4 (DTG 010153Z0). REFER TO TROPICAL CYCLONE 30P (NATHAN) WARNINGS (WTPS32 PGTW) FOR FINAL WARNING.// ========================================================================= WTPS31 PGTW 980331 15:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 004 01 ACTIVE TROPICAL CYCLONE IN SOUTHWEST PACIFIC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 311200Z7 --- 14.3S8 167.4E8 MOVEMENT PAST SIX HOURS - 250 DEGREES AT 05 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE AND SYNOPTIC DATA PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 025 NM RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE OVER WATER 055 NM ELSEWHERE REPEAT POSIT: 14.3S8 167.4E8 --- FORECASTS: 12 HRS, VALID AT: 010000Z1 --- 14.7S2 166.6E9 MAX SUSTAINED WINDS - 080 KT, GUSTS 095 KT RADIUS OF 050 KT WINDS - 030 NM SOUTHEAST SEMICIRCLE OVER WATER 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE OVER WATER 080 NM ELSEWHERE OVER WATER VECTOR TO 24 HR POSIT: 250 DEG/ 06 KTS --- 24 HRS, VALID AT: 011200Z4 --- 15.1S7 165.5E7 MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 035 NM SOUTH SEMICIRCLE 025 NM ELSEWHERE RADIUS OF 035 KT WINDS - 090 NM SOUTH SEMICIRCLE OVER WATER 075 NM ELSEWHERE VECTOR TO 36 HR POSIT: 255 DEG/ 08 KTS --- 36 HRS, VALID AT: 020000Z2 --- 15.5S1 164.0E1 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 040 NM SOUTH SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 100 NM SOUTH SEMICIRCLE 085 NM ELSEWHERE VECTOR TO 48 HR POSIT: 265 DEG/ 12 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 021200Z5 --- 15.8S4 161.5E3 MAX SUSTAINED WINDS - 100 KT, GUSTS 120 KT RADIUS OF 050 KT WINDS - 045 NM SOUTH SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 110 NM SOUTH SEMICIRCLE 100 NM ELSEWHERE --- REMARKS: TROPICAL CYCLONE 31P (ZUMAN) IS MOVING WEST-SOUTHWESTWARD AT 05 KNOTS. THE WARNING POSITION AND INTENSITY ARE BASED ON 311130Z9 INFRARED SATELLITE IMAGERY AUGMENTED BY 310833Z8 MICROWAVE DATA. ANIMATED INFRARED SATELLITE IMAGERY SHOWS CENTRAL DEEP CONVECTION HAS EXPANDED AND CLOUD TOP TEMPERATURES HAVE COOLED OVER THE PAST 06 HOURS. 310833Z8 MICROWAVE DATA INDICATES AN EYEWALL FEATURE FORMING AROUND THE LOW-LEVEL CIRCULATION CENTER. TROPICAL CYCLONE 31P (ZUMAN) IS FORECAST TO CONTINUE INTENSIFYING THROUGHOUT THE FORECAST PERIOD AS IT IS STEERED GENERALLY WEST-SOUTHWESTWARD BY THE SUBTROPICAL RIDGE TO ITS SOUTH. THIS TRACK FORECAST IS SUPPORTED BY ALL OF OUR DYNAMIC OBJECTIVE FORECAST GUIDANCE. AN ALTERNATE TRACK IS SUG- GESTED BY THE MAJORITY OF OUR STATISTICAL AND CLIMATOLOGICAL OBJECTIVE AIDS WHEREIN AN APPROACHING MID-LATITUDE TROUGH WEAKENS THE RIDGE TO THIS SYSTEM=S SOUTH, ALLOWING TROPICAL CYCLONE 31P (ZUMAN) TO RECURVE INTO THE MID-LATITUDE WEST- ERLIES. THE PROBABILITY OF THIS ALTERNATE SCENARIO IS LOW. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 311200Z7 IS 19 FEET. NEXT WARNINGS AT 010300Z4 (DTG 010153Z0) AND 011500Z7 (DTG 011353Z3).// ========================================================================= WTPS31 PGTW 980401 03:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 005 02 ACTIVE TROPICAL CYCLONES IN SOUTHWEST PACIFIC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 010000Z1 --- 15.6S2 166.2E5 MOVEMENT PAST SIX HOURS - 220 DEGREES AT 10 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 030 NM SOUTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE OVER WATER 050 NM ELSEWHERE OVER WATER REPEAT POSIT: 15.6S2 166.2E5 --- FORECASTS: 12 HRS, VALID AT: 011200Z4 --- 16.8S5 164.9E0 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 030 NM SOUTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 080 NM SOUTHEAST SEMICIRCLE 065 NM ELSEWHERE VECTOR TO 24 HR POSIT: 230 DEG/ 09 KTS --- 24 HRS, VALID AT: 020000Z2 --- 17.9S7 163.5E5 MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT RADIUS OF 050 KT WINDS - 035 NM SOUTHEAST SEMICIRCLE 025 NM ELSEWHERE RADIUS OF 035 KT WINDS - 085 NM SOUTHEAST SEMICIRCLE 070 NM ELSEWHERE VECTOR TO 36 HR POSIT: 240 DEG/ 09 KTS --- 36 HRS, VALID AT: 021200Z5 --- 18.7S6 161.9E7 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 035 NM SOUTH SEMICIRCLE 025 NM ELSEWHERE RADIUS OF 035 KT WINDS - 090 NM SOUTH SEMICIRCLE 075 NM ELSEWHERE VECTOR TO 48 HR POSIT: 250 DEG/ 09 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 030000Z3 --- 19.3S3 160.2E9 MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 035 NM SOUTH SEMICIRCLE 025 NM ELSEWHERE RADIUS OF 035 KT WINDS - 100 NM SOUTH SEMICIRCLE 080 NM ELSEWHERE --- REMARKS: 010300Z4 POSITION 15.9S5 165.9E1. TROPICAL CYCLONE 31P (ZUMAN) IS MOVING SOUTHWESTWARD AT 10 KNOTS. THE WARNING POSITION IS BASED ON 312330Z2 VISIBLE SATELLITE IMAGERY, 311936Z3 MICROWAVE IMAGERY, AND SYNOPTIC DATA FROM PEKOA AIRPORT (WMO 91554). THE WARNING INTENSITY OF 90 KNOTS IS BASED ON A SATELLITE-DERIVED DVORAK CURRENT INTENSITY ESTIMATE OF CI5.0. THE CENTRAL CONVECTION OF THIS SYSTEM IS CURRENTLY SHOWING SIGNS OF WEAKENING (WARMING) AND AREAL EXTENT HAS DECREASED OVER THE PAST 3-HOURS. ANIMATED WATER VAPOR IMAGERY INDICATES THAT UPPER LEVEL OUTFLOW CONTINUES TO BE FAVORABLE. TC 31P (ZUMAN) IS EXPECTED TO CONTINUE ITS SOUTHWESTWARD TRACK THROUGH 36 HOURS, FOLLOWED BY A SLIGHTLY MORE WESTWARD COURSE AS THE SUBTROPICAL RIDGE BUILDS SOUTH OF THE SYSTEM. TC 31P (ZUMAN) SHOULD INTENSIFY THROUGH THE 24-HOUR FORECAST PERIOD AND THEN BEGIN TO SLOWLY WEAKEN AS IT ENTERS AN AREA OF INCREASED VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 010000Z IS 20 FEET. NEXT WARNINGS AT 011500Z7 (DTG 011353Z3) AND 020300Z5 (DTG 020153Z1).// ========================================================================= WTPS31 PGTW 980401 15:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 006 01 ACTIVE TROPICAL CYCLONE IN SOUTHWEST PACIFIC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 011200Z4 --- 15.6S2 165.7E9 MOVEMENT PAST SIX HOURS - 250 DEGREES AT 03 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 030 NM SOUTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM SOUTHEAST SEMICIRCLE OVER WATER 070 NM ELSEWHERE REPEAT POSIT: 15.6S2 165.7E9 --- FORECASTS: 12 HRS, VALID AT: 020000Z2 --- 15.8S4 165.1E3 MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM SOUTHEAST SEMICIRCLE 070 NM ELSEWHERE VECTOR TO 24 HR POSIT: 245 DEG/ 05 KTS --- 24 HRS, VALID AT: 021200Z5 --- 16.2S9 164.1E2 MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT RADIUS OF 050 KT WINDS - 045 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM SOUTHEAST SEMICIRCLE 070 NM ELSEWHERE VECTOR TO 36 HR POSIT: 255 DEG/ 07 KTS --- 36 HRS, VALID AT: 030000Z3 --- 16.6S3 162.7E6 MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 040 NM SOUTH SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 090 NM SOUTH SEMICIRCLE 065 NM ELSEWHERE VECTOR TO 48 HR POSIT: 260 DEG/ 12 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 031200Z6 --- 17.0S8 160.3E0 MAX SUSTAINED WINDS - 080 KT, GUSTS 095 KT RADIUS OF 050 KT WINDS - 040 NM SOUTH SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 090 NM SOUTH SEMICIRCLE 070 NM ELSEWHERE --- REMARKS: TROPICAL CYCLONE 31P (ZUMAN) IS MOVING SLOWLY TOWARD THE WEST-SOUTHWEST IN WEAK ENVIRONMENTAL STEERING FLOW. THE WARNING POSITION AND INTENSITY ARE BASED ON 011130Z6 INFRARED SATELLITE IMAGERY. THIS SYSTEM HAS REINTENSIFIED AFTER WEAKENING DUE TO INTERACTION WITH THE ISLAND OF ESPIRITU SANTO. ANIMATED INFRARED SATELLITE IMAGERY SHOWS REDEVELOPMENT OF CENTRAL DEEP CONVECTION WITH GOOD UPPER- LEVEL OUTFLOW IN ALL QUADRANTS. TROPICAL CYCLONE 31P (ZUMAN) IS FORECAST TO ACCELERATE TOWARD THE WEST-SOUTHWEST AS THE SUBTROPICAL RIDGE TO ITS SOUTH STRENGTHENS. THIS SYSTEM IS EXPECTED TO INTENSIFY THROUGH 24 HOURS THEN SLOWLY WEAKEN AS IT ENTERS A REGION OF LIGHT VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 011200Z4 IS 18 FEET. NEXT WARNINGS AT 020300Z5 (DTG 020153Z1) AND 021500Z8 (DTG 021353Z4).// ========================================================================= WTPS31 PGTW 980402 03:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 007 01 ACTIVE TROPICAL CYCLONE IN SOUTHWEST PACIFIC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 020000Z2 --- 15.7S3 164.2E3 MOVEMENT PAST SIX HOURS - 270 DEGREES AT 09 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 RADIUS OF 050 KT WINDS - 035 NM SOUTH SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM SOUTH SEMICIRCLE 070 NM ELSEWHERE REPEAT POSIT: 15.7S3 164.2E3 --- FORECASTS: 12 HRS, VALID AT: 021200Z5 --- 15.8S4 162.9E8 MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 035 NM SOUTH SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM SOUTH SEMICIRCLE 070 NM ELSEWHERE VECTOR TO 24 HR POSIT: 270 DEG/ 07 KTS --- 24 HRS, VALID AT: 030000Z3 --- 15.8S4 161.5E3 MAX SUSTAINED WINDS - 080 KT, GUSTS 095 KT RADIUS OF 050 KT WINDS - 020 NM NORTH SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 065 NM NORTH SEMICIRCLE 090 NM ELSEWHERE VECTOR TO 36 HR POSIT: 265 DEG/ 05 KTS --- 36 HRS, VALID AT: 031200Z6 --- 15.9S5 160.5E2 MAX SUSTAINED WINDS - 070 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 020 NM NORTH SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 090 NM SOUTH SEMICIRCLE 065 NM ELSEWHERE VECTOR TO 48 HR POSIT: 265 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 040000Z4 --- 16.0S7 159.6E1 MAX SUSTAINED WINDS - 060 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 025 NM SOUTH SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 080 NM SOUTH SEMICIRCLE 060 NM ELSEWHERE --- REMARKS: 020300Z5 POSITION 15.7S3 163.9E9. TROPICAL CYCLONE 31P (ZUMAN) HAS TRACKED WESTWARD AT 09 KNOTS FOR THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 012330Z9 VISIBLE SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON A 012330Z9 SATELLITE DVORAK INTENSITY ESTIMATE OF 90 KNOTS. THE SYSTEM HAS BEEN UNDER THE INFLUENCE OF A STRONG RIDGE OF HIGH PRESSURE BUILDING TO ITS SOUTH. THIS RIDGE WILL CONTINUE TO BE THE PRIMARY STEERING FLOW FOR TROPICAL CYCLONE 31P (ZUMAN) THROUGHOUT THE FORECAST PERIOD. THE RIDGE IS ALSO EXPECTED TO MAINTAIN THE SYSTEMS FORWARD SPEED FOR THE GREATER PART OF THE 48 HOUR PERIOD. THE INTENSITY IS EXPECTED TO GRADUALLY WEAKEN AS THE SYSTEM IS EXPECTED TO SUFFER MORE VERTICAL WIND SHEAR THROUGH THE REMAINDER OF THE PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 020000Z2 IS 23 FEET. NEXT WARNINGS AT 021500Z8 (DTG 021353Z4) AND 030300Z6 (DTG 30153Z2).// ========================================================================= WTPS31 PGTW 980402 15:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY IMMEDIATE DELIVERY REQ TO SCRIPPS LA JOLLA SCRIPPS LA JOLLA REQ PASS TO RV ROGER REVELLE 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 008 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 021200Z5 --- 16.0S7 163.2E2 MOVEMENT PAST SIX HOURS - 240 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 040 NM SOUTH SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM SOUTH SEMICIRCLE 090 NM ELSEWHERE REPEAT POSIT: 16.0S7 163.2E2 --- FORECASTS: 12 HRS, VALID AT: 030000Z3 --- 16.3S0 162.5E4 MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 040 NM SOUTH SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM SOUTH SEMICIRCLE 090 NM ELSEWHERE VECTOR TO 24 HR POSIT: 260 DEG/ 05 KTS --- 24 HRS, VALID AT: 031200Z6 --- 16.5S2 161.5E3 MAX SUSTAINED WINDS - 080 KT, GUSTS 095 KT RADIUS OF 050 KT WINDS - 035 NM SOUTH SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 090 NM SOUTH SEMICIRCLE 085 NM ELSEWHERE VECTOR TO 36 HR POSIT: 260 DEG/ 05 KTS --- 36 HRS, VALID AT: 040000Z4 --- 16.7S4 160.4E1 MAX SUSTAINED WINDS - 070 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 025 NM SOUTH SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 085 NM SOUTH SEMICIRCLE 080 NM ELSEWHERE VECTOR TO 48 HR POSIT: 260 DEG/ 05 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 041200Z7 --- 16.9S6 159.4E9 MAX SUSTAINED WINDS - 060 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 025 NM SOUTH SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 080 NM SOUTH SEMICIRCLE 075 NM ELSEWHERE --- REMARKS: 021500Z8 POSITION 16.1S8 163.0E0. TROPICAL CYCLONE 31P (ZUMAN) HAS TRACKED WEST-SOUTHWESTWARD AT 4 KNOTS FOR THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 021130Z7 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON 021130Z7 SATELLITE INTENSITY ESTIMATE OF 90 KNOTS AND CONTINUITY WITH THE PREVIOUS WARNING. ANIMATED INFRARED AND WATER VAPOR SATELLITE IMAGERY SUGGESTS THAT A PASSING MID-LEVEL TROUGH IS INTRODUCING A WEAKNESS IN THE SUBTROPICAL RIDGE LOCATED SOUTH OF THE SYSTEM. TROPICAL CYCLONE 31P (ZUMAN) HAS BEGUN MOVING SLOWLY WEST-SOUTHWESTWARD IN RESPONSE TO THIS WEAKENING IN THE STEERING FLOW WHICH SHOULD CONTINUE THROUGHOUT THE 12 HOUR FORECAST POSITION. AFTER THE 12 HOUR POSITION, THE SUBTROPICAL RIDGE SHOULD RE-BUILD SLIGHTLY BUT THE STEERING FLOW ON THE SYSTEM SHOULD REMAIN WEAK THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD. TROPICAL CYCLONE 31P (ZUMAN) SHOULD BEGIN A DECREASE IN INTENSITY BY THE 36 HOUR POSITION AS THE SYSTEM MOVES INTO AN AREA OF INCREASING VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 021200Z IS 23 FEET. NEXT WARNINGS AT 022100Z5 (DTG 021953Z0), 030300Z6 (DTG 030153Z2), 030900Z2 (DTG 030753Z8), AND 031500Z9 (DTG 031353Z5).// ========================================================================= WTPS31 PGTW 980302 21:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY IMMEDIATE DELIVERY REQ TO SCRIPPS LA JOLLA CA SCRIPPS LA JOLLA CA REQ PASS TO RV ROGER REVELLE 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 009 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 021800Z1 --- 16.1S8 162.9E8 MOVEMENT PAST SIX HOURS - 250 DEGREES AT 03 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 040 NM SOUTH SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 095 NM SOUTH SEMICIRCLE 090 NM ELSEWHERE REPEAT POSIT: 16.1S8 162.9E8 --- FORECASTS: 12 HRS, VALID AT: 030600Z9 --- 16.3S0 162.4E3 MAX SUSTAINED WINDS - 080 KT, GUSTS 095 KT RADIUS OF 050 KT WINDS - 035 NM SOUTH SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 090 NM SOUTH SEMICIRCLE 085 NM ELSEWHERE VECTOR TO 24 HR POSIT: 255 DEG/ 04 KTS --- 24 HRS, VALID AT: 031800Z2 --- 16.5S2 161.5E3 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 030 NM SOUTH SEMICIRCLE 025 NM ELSEWHERE RADIUS OF 035 KT WINDS - 085 NM SOUTH SEMICIRCLE 080 NM ELSEWHERE VECTOR TO 36 HR POSIT: 255 DEG/ 05 KTS --- 36 HRS, VALID AT: 040600Z0 --- 16.8S5 160.4E1 MAX SUSTAINED WINDS - 070 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 025 NM SOUTH SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 080 NM SOUTH SEMICIRCLE 075 NM ELSEWHERE VECTOR TO 48 HR POSIT: 255 DEG/ 05 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 041800Z3 --- 17.1S9 159.3E8 MAX SUSTAINED WINDS - 060 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 020 NM SOUTH SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 075 NM SOUTH SEMICIRCLE 070 NM ELSEWHERE --- REMARKS: 022100Z5 POSITION 16.1S8 162.8E7. TROPICAL CYCLONE 31P (ZUMAN) HAS TRACKED WEST-SOUTHWEST AT 3 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 021730Z3 INFRARED SATELLITE IMAGERY. THE WARNING POSITION IS BASED ON A 021730Z3 SATELLITE INTENSITY ESTIMATE OF 90 KNOTS AND A 021731Z4 SATELLITE INTENSITY ESTIMATE OF 80 KNOTS. TROPICAL CYCLONE 31P (ZUMAN) CONTINUES TO SLOWLY TRACK WEST-SOUTHWESTWARD UNDER THE INFLUENCE OF WEAK STEERING FLOW FROM THE SUBTROPICAL RIDGE LOCATED SOUTH OF THE SYSTEM. THE SUBTROPICAL RIDGE SHOULD GRADUALLY RE-BUILD OVER THE NEXT 24 HOURS BUT REMAIN WEAK KEEPING TROPICAL CYCLONE 31P (ZUMAN) TRACKING SLOWLY WEST- SOUTHWESTWARD THROUGHOUT THE FORECAST PERIOD. TROPICAL CYCLONE 31P (ZUMAN) SHOULD CONTINUE TO SLOWLY WEAKEN THROUGHOUT THE FORECAST PERIOD AS IT ENCOUNTERS INCREASING VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 021800Z IS 23 FEET. NEXT WARNINGS AT 030300Z6 (DTG 030153Z2), 030900Z2 (DTG 030753Z8), 031500Z9 (DTG 031353Z5), AND 032100Z6 (DTG 031953Z1).// ========================================================================= WTPS31 PGTW 980403 03:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY IMMEDIATE DELIVERY REQ TO SCRIPPS LA JOLLA CA SCRIPPS LA JOLLA CA REQ PASS TO RV ROGER REVELLE 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 010 01 ACTIVE TROPICAL CYCLONE IN SOUTHWEST PACIFIC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 030000Z3 --- 15.4S0 161.9E7 MOVEMENT PAST SIX HOURS - 280 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 025 NM RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE REPEAT POSIT: 15.4S0 161.9E7 --- FORECASTS: 12 HRS, VALID AT: 031200Z6 --- 15.3S9 160.8E5 MAX SUSTAINED WINDS - 080 KT, GUSTS 095 KT RADIUS OF 050 KT WINDS - 025 NM RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE VECTOR TO 24 HR POSIT: 265 DEG/ 05 KTS --- 24 HRS, VALID AT: 040000Z4 --- 15.4S0 159.8E3 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE VECTOR TO 36 HR POSIT: 255 DEG/ 05 KTS --- 36 HRS, VALID AT: 041200Z7 --- 15.7S3 158.8E2 MAX SUSTAINED WINDS - 070 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE VECTOR TO 48 HR POSIT: 230 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 050000Z5 --- 16.2S9 158.2E6 MAX SUSTAINED WINDS - 060 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE --- REMARKS: 030300Z6 POSITION 15.4S0 161.6E4. OVER THE PAST 6 HOURS, TROPICAL CYCLONE 31P (ZUMAN) HAS TRACKED TOWARDS THE WEST AT 6 KNOTS. THE TRACK HAS BEEN ADJUSTED SLIGHTLY TOWARDS THE NORTH BASED ON VISIBLE SATELLITE IMAGERY. ADDITIONALLY, THE CURRENT WIND RADII HAVE BEEN ADJUSTED BASED ON INFRARED SATELLITE IMAGERY. THE WARNING POSITION IS BASED ON A COMBINATION OF 022330Z0 VISIBLE SATELLITE IMAGERY AND 022117Z3 MICROWAVE IMAGERY. THE WARNING INTENSITY IS BASED ON A COMBINATION OF SATELLITE DERIVED CURRENT INTENSITY ESTIMATES BETWEEN 77 AND 90 KNOTS. THE FORECAST REMAINS SIMILAR AS THE STORM IS EXPECTED TO TRACK MORE TOWARDS THE SOUTH AT THE 36 HOUR PERIOD AS A MID-LATITUDE TROUGH OVER AUSTRALIA PASSES THROUGH THE AREA. NUMERICAL GUIDANCE SUGGESTS TROPICAL CYCLONE 31P WILL TURN TOWARDS THE SOUTH BY THE 12 HOUR PERIOD. HOWEVER, THE FORECAST TRACK FOLLOWS PERSISTENCE WHICH SUGGESTS THE SYSTEM WILL CONTINUE TOWARDS THE WEST THROUGH THE 24 HOUR PERIOD. TROPICAL CYCLONE 31P IS FORECAST TO SLOW TO 4 KNOTS BY THE END OF THE FORECAST PERIOD AS THE PREDOMINANT STEERING FLOW WEAKENS. ADDITIONALLY, THE SYSTEM IS EXPECTED TO SLOWLY WEAKEN THROUGHOUT THE FORECAST PERIOD AS VERTICAL WIND SHEER IS FORECAST TO INCREASE. SUBSEQUENT WARNINGS WILL BE ISSUED AT TWELVE-HOURLY INTERVALS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 030000Z IS 21 FEET. NEXT WARNINGS AT 031500Z9 (DTG 031353Z5) AND 040300Z7 (DTG 040153Z3).// ========================================================================= WTPS31 PGTW 980403 15:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY IMMEDIATE DELIVERY REQ TO SCRIPPS LA JOLLA CA SCRIPPS LA JOLLA CA REQ PASS TO RV ROGER REVELLE 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 011 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 031200Z6 --- 15.6S2 161.7E5 MOVEMENT PAST SIX HOURS - 250 DEGREES AT 03 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 080 KT, GUSTS 095 KT RADIUS OF 050 KT WINDS - 025 NM RADIUS OF 035 KT WINDS - 075 NM REPEAT POSIT: 15.6S2 161.7E5 --- FORECASTS: 12 HRS, VALID AT: 040000Z4 --- 15.8S4 161.2E0 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 070 NM VECTOR TO 24 HR POSIT: 250 DEG/ 03 KTS --- 24 HRS, VALID AT: 041200Z7 --- 16.0S7 160.6E3 MAX SUSTAINED WINDS - 070 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE 055 NM ELSEWHERE VECTOR TO 36 HR POSIT: 230 DEG/ 05 KTS --- 36 HRS, VALID AT: 050000Z5 --- 16.7S4 159.8E3 MAX SUSTAINED WINDS - 065 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 015 NM RADIUS OF 035 KT WINDS - 060 NM SOUTHEAST SEMICIRCLE 050 NM ELSEWHERE VECTOR TO 48 HR POSIT: 200 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 051200Z8 --- 17.9S7 159.4E9 MAX SUSTAINED WINDS - 060 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 015 NM RADIUS OF 035 KT WINDS - 055 NM EAST SEMICIRCLE 045 NM ELSEWHERE --- REMARKS: 031500Z9 POSITION 15.6S2 161.6E4. TROPICAL CYCLONE 31P (ZUMAN) HAS TRACKED WEST-SOUTHWESTWARD AT 3 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 031130Z8 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON A 031130Z8 SATELLITE INTENSITY ESTIMATE OF 80 KNOTS. TROPICAL CYCLONE 31P (ZUMAN) HAS BEEN SLOWLY DRIFTING WEST- SOUTHWESTWARD UNDER THE INFLUENCE OF WEAK MID-LEVEL STEERING FLOW FROM THE SUBTROPICAL RIDGE. THE SYSTEM SHOULD REMAIN QUASI- STATIONARY FOR THE NEXT 12 HOURS AND THEN GRADUALLY BEGIN TRACKING SOUTHWESTWARD BY THE 24 THROUGH 36 HOUR FORECAST POSITIONS AS AN APPROACHING MID-LATITUDE TROUGH IS FORECAST TO FURTHER WEAKEN THE SUBTROPICAL RIDGE. TROPICAL CYCLONE 31P (ZUMAN) SHOULD BEGIN TRACKING SOUTH-SOUTHWESTWARD BY 48 HOURS AS THE MID-LATITUDE TROUGH PASSES. TROPICAL CYCLONE 31P (ZUMAN) SHOULD CONTINUE TO GRADUALLY WEAKEN IN INTENSITY THROUGHOUT THE FORECAST PERIOD AS IT ENCOUNTERS INCREASING VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 031200Z IS 17 FEET. NEXT WARNINGS AT 040300Z7 (DTG 040153Z3) AND 041500Z0 (DTG 041353Z6).// ========================================================================= WTPS31 PGTW 980404 03:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 012 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 040000Z4 --- 16.6S3 161.5E3 MOVEMENT PAST SIX HOURS - 195 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE REPEAT POSIT: 16.6S3 161.5E3 --- FORECASTS: 12 HRS, VALID AT: 041200Z7 --- 17.6S4 161.3E1 MAX SUSTAINED WINDS - 055 KT, GUSTS 065 KT RADIUS OF 050 KT WINDS - 015 NM RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 24 HR POSIT: 180 DEG/ 06 KTS --- 24 HRS, VALID AT: 050000Z5 --- 18.8S7 161.3E1 MAX SUSTAINED WINDS - 055 KT, GUSTS 065 KT RADIUS OF 050 KT WINDS - 015 NM RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 36 HR POSIT: 170 DEG/ 08 KTS --- 36 HRS, VALID AT: 051200Z8 --- 20.3S5 161.6E4 MAX SUSTAINED WINDS - 050 KT, GUSTS 060 KT RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 48 HR POSIT: 155 DEG/ 10 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 060000Z6 --- 22.2S6 162.5E4 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE 030 NM ELSEWHERE --- REMARKS: 040300Z7 POSITION 16.9S6 161.5E3. TROPICAL CYCLONE 31P (ZUMAN) IS TRACKING SOUTH-SOUTHWESTWARD AT 04 KNOTS. THE WARNING POSITION IS BASED ON 032330Z1 VISIBLE SATELLITE IMAGERY AND 032118Z5 MICROWAVE IMAGERY. THE WARNING INTENSITY OF 65 KNOTS IS BASED ON A SATELLITE-DERIVED DVORAK CURRENT INTENSITY ESTIMATE OF CI4.0. THE LATEST SATELLITE IMAGERY IS INDICATING THAT THE LOW-LEVEL CIRCULATION CENTER ASSOCIATED WITH TC 31P (ZUMAN) IS LOCATED TO THE NORTHWEST OF THE DEEPEST CONVECTION. THE SYSTEM IS EXPECTED TO TRACK SOUTHWARD THROUGH THE SUBTROPICAL RIDGE AS A MID-LATITUDE TROUGH APPROACHES FROM THE WEST. TC 31P (ZUMAN) IS FORECAST TO GRADUALLY WEAKEN THROUGHOUT THE FORECAST PERIOD AS IT ENCOUNTERS INCREASING VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 040000Z IS 17 FEET. NEXT WARNINGS AT 041500Z0 (DTG 041353Z6) AND 050300Z8 (DTG 050153Z4).// ========================================================================= WTPS31 PGTW 980404 15:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 013 01 ACTIVE TROPICAL CYCLONE IN SOUTHWEST PACIFIC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 041200Z7 --- 17.8S6 162.2E1 MOVEMENT PAST SIX HOURS - 150 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 055 KT, GUSTS 065 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 070 NM NORTHEAST SEMICIRCLE 045 NM ELSEWHERE REPEAT POSIT: 17.8S6 162.2E1 --- FORECASTS: 12 HRS, VALID AT: 050000Z5 --- 19.2S2 163.0E0 MAX SUSTAINED WINDS - 050 KT, GUSTS 060 KT BECOMING EXTRATROPICAL RADIUS OF 035 KT WINDS - 065 NM NORTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 24 HR POSIT: 150 DEG/ 11 KTS --- 24 HRS, VALID AT: 051200Z8 --- 21.0S3 164.2E3 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT BECOMING EXTRATROPICAL RADIUS OF 035 KT WINDS - 060 NM NORTHEAST SEMICIRCLE OVER WATER 030 NM ELSEWHERE VECTOR TO 36 HR POSIT: 140 DEG/ 14 KTS --- 36 HRS, VALID AT: 060000Z6 --- 23.2S7 166.2E5 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT EXTRATROPICAL RADIUS OF 035 KT WINDS - 060 NM NORTHEAST SEMICIRCLE 025 NM ELSEWHERE --- REMARKS: TROPICAL CYCLONE 31P (ZUMAN) IS MOVING TOWARD THE SOUTHEAST AT 06 KNOTS. THE WARNING POSITION AND INTENSITY ARE BASED ON 041130Z9 INFRARED SATELLITE IMAGERY AUGMENTED BY 040731Z5 MICROWAVE DATA. ANIMATED INFRARED SATELLITE IMAGERY SHOWS AN UPPER-LEVEL TROUGH TO THE SOUTHWEST IS CREATING MODERATE VERTICAL WIND SHEAR OVER THIS SYSTEM. HOWEVER, TROPICAL CYCLONE 31P (ZUMAN) HAS REDEVELOPED CENTRAL DEEP CONVECTION OVER THE PAST 03 HOURS. THIS SYSTEM IS FORECAST TO ACCELERATE TO THE SOUTHEAST AS IT BEGINS TRANSITIONING TO AN EXTRA- TROPICAL SYSTEM. TROPICAL CYCLONE 31P (ZUMAN) IS EXPECTED TO WEAKEN SLOWLY DUE TO VERTICAL WIND SHEAR THEN MAINTAIN ITS INTENSITY AS ITS FORWARD MOTION INCREASES. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 041200Z7 IS 17 FEET. NEXT WARNINGS AT 050300Z8 (DTG 050153Z4) AND 051500Z1 (051353Z7).// ========================================================================= WTPS31 PGTW 980405 03:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 014 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 050000Z5 --- 19.6S6 164.1E2 MOVEMENT PAST SIX HOURS - 135 DEGREES AT 12 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE AND SYNOPTIC DATA PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 050 KT, GUSTS 060 KT BECOMING EXTRATROPICAL RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE OVER WATER REPEAT POSIT: 19.6S6 164.1E2 --- FORECASTS: 12 HRS, VALID AT: 051200Z8 --- 21.6S9 166.1E4 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT BECOMING EXTRATROPICAL RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE OVER WATER 035 NM ELSEWHERE OVER WATER VECTOR TO 24 HR POSIT: 145 DEG/ 15 KTS --- 24 HRS, VALID AT: 060000Z6 --- 23.8S3 168.2E7 MAX SUSTAINED WINDS - 035 KT, GUSTS 040 KT EXTRATROPICAL --- REMARKS: 050300Z8 POSITION 20.1S3 164.6E7. TROPICAL CYCLONE 31P (ZUMAN) IS TRACKING SOUTHEASTWARD AT 12 KNOTS. THE WARNING POSITION AND INTENSITY ARE BASED ON 052330Z3 VISIBLE SATELLITE IMAGERY, 042106Z3 MICROWAVE IMAGERY AND AVAILABLE SYNOPTIC DATA. THE LOW-LEVEL CIRCULATION CENTER IS NOW COMPLETELY EXPOSED AND THE DEEP CONVECTION ASSOCIATED WITH THIS SYSTEM IS 32 NM EAST OF THE CENTER. TROPICAL CYCLONE 31P (ZUMAN) IS EXPECTED TO CONTINUE TRACKING SOUTHEASTWARD AND ACCELERATE. THE SYSTEM IS FORECAST TO SLOWLY WEAKEN DUE TO THE INCREASING VERTICAL WIND SHEAR AND THEN MAINTAIN INTENSITY AS ITS FORWARD MOTION INCREASES. EXTRATROPICAL TRANSITION SHOULD BE COMPLETED NEAR THE 24-HOUR FORECAST POSITION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 050000Z IS 15 FEET. NEXT WARNINGS AT 051500Z1 (DTG 051353Z7).// ========================================================================= WTPS31 PGTW 980405 15:00z IMMEDIATE DELIVERY REQ TO AMEMBASSY SUVA AMEMBASSY SUVA REQ PASS TO USAID OFDA ADVISOR IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT MORESBY 1. TROPICAL CYCLONE 31P (ZUMAN) WARNING NR 015 01 ACTIVE TROPICAL CYCLONE IN SOUTHWEST PACIFIC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 051200Z8 --- 20.8S0 166.0E3 MOVEMENT PAST SIX HOURS - 120 DEGREES AT 12 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT BECOMING EXTRATROPICAL RADIUS OF 035 KT WINDS - 060 NM NORTHEAST SEMICIRCLE 040 NM ELSEWHERE REPEAT POSIT: 20.8S0 166.0E3 --- FORECASTS: 12 HRS, VALID AT: 060000Z6 --- 22.5S9 168.6E1 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT EXTRATROPICAL --- REMARKS: 051500Z1 POSITION: 21.1S4 166.5E8 TROPICAL CYCLONE 31P (ZUMAN) IS MOVING SOUTHEASTWARD AT 12 KNOTS. THE WARNING POSITION AND INTENSITY ARE BASED ON 051130Z0 INFRARED SATELLITE IMAGERY. ANIMATED INFRARED SATELLITE IMAGERY SHOWS AN EXPOSED LOW-LEVEL CIRCULATION CENTER WITH DEEP CONVECTION TO ITS EAST. NO CHANGE TO FORECAST REASONING. TROPICAL CYCLONE 31P (ZUMAN) IS EXPECTED TO CONTINUE MOVING TOWARD THE SOUTHEAST AND COMPLETE ITS TRANSITION TO AN EXTRA- TROPICAL SYSTEM BY THE 12 HOUR FORECAST POSITION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051200Z8 IS 15 FEET. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE NAVAL PACIFIC METEOROLOGY AND OCEANOGRAPHY CENTER WEST / JOINT TYPHOON WARNING CENTER (NAVPACMETOCCEN WEST/JTWC). THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION.//
Tropical cyclone tracks developed by Michael Bath using operational warnings and advisories.
Document: tropical_cyclone_zuman_jtwc_advisories.htm
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