Updated: 17 June 2020
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| Tropical Cyclones
[Index] | Tropical Cyclone 199918 : JTWC Advisories |
| Season 1998-1999 Summaries (Operational Data): [AU] [SIO] [SPAC] [SH] | |
| ---> Tropical Cyclone 199918 Track Map and Data |
WTXS21 PGTW 990204 03:00z
SUBJ/TROPICAL CYCLONE FORMATION ALERT
040255Z FEB 99//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 15.8S4 120.6E9 TO 21.2S5
112.8E2 WITHIN THE NEXT 12 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 25 KNOTS.
METSAT IMAGERY AT 040030Z INDICATES THAT A CIRCULATION CENTER IS
LOCATED NEAR 16.7S4 119.7E8. THE SYSTEM IS MOVING SOUTH-
SOUTHWESTWARD AT 02 KNOTS.
2. REMARKS: THIS TROPICAL DISTURBANCE HAS RECENTLY DEVELOPED DEEP
CONVECTION NEAR THE LOW-LEVEL CIRCULATION CENTER. THIS DISTURBANCE
HAS GOOD UPPER-LEVEL OUTFLOW IN THE WESTERN QUADRANT, FAIR
ELSEWHERE. 031500Z9 SCATTEROMETER REVEALED A SYMMETRICAL LOW-LEVEL
CIRCULATION WITH WINDS OF 20 KNOTS AT THE PERIPHERY OF THE
DISTURBANCE. IT IS ANTICIPATED THAT THE DEVELOPMENT OF DEEP
CONVECTION WILL CONSOLIDATE STRONGER WINDS TOWARD THE CENTER AND
LEAD TO FURTHER ORGANIZATION. ACCORDINGLY, THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN 24 HOURS IS
GOOD.
3. THIS ALERT VALID UNTIL 050300Z8.//
=========================================================================
WTXS31 PGTW 990204 21:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 001
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
041800Z3 --- NEAR 17.9S7 116.0E8
MOVEMENT PAST SIX HOURS - 250 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
RADIUS OF 035 KT WINDS - 180 NM SOUTHEAST SEMICIRCLE
140 NM ELSEWHERE
REPEAT POSIT: 17.9S7 116.0E8
---
FORECASTS:
12 HRS, VALID AT:
050600Z1 --- 18.4S3 114.4E0
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 195 NM SOUTHEAST SEMICIRCLE
OVER WATER
150 NM ELSEWHERE
VECTOR TO 24 HR POSIT: 255 DEG/ 07 KTS
---
24 HRS, VALID AT:
051800Z4 --- 18.8S7 112.9E3
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 215 NM SOUTHEAST SEMICIRCLE
OVER WATER
165 NM ELSEWHERE
VECTOR TO 36 HR POSIT: 255 DEG/ 07 KTS
---
36 HRS, VALID AT:
060600Z2 --- 19.1S1 111.5E8
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
RADIUS OF 050 KT WINDS - 025 NM
RADIUS OF 035 KT WINDS - 220 NM SOUTHEAST SEMICIRCLE
170 NM ELSEWHERE
VECTOR TO 48 HR POSIT: 255 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
061800Z5 --- 19.4S4 110.1E3
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
RADIUS OF 050 KT WINDS - 040 NM SOUTH SEMICIRCLE
025 NM ELSEWHERE
RADIUS OF 035 KT WINDS - 230 NM SOUTH SEMICIRCLE
175 NM ELSEWHERE
VECTOR TO 72 HR POSIT: 265 DEG/ 07 KTS
---
72 HRS, VALID AT:
071800Z6 --- 19.7S7 107.1E9
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
RADIUS OF 050 KT WINDS - 045 NM SOUTH SEMICIRCLE
030 NM ELSEWHERE
RADIUS OF 035 KT WINDS - 235 NM SOUTH SEMICIRCLE
180 NM ELSEWHERE
---
REMARKS:
042100Z7 POSITION NEAR 18.0S9 115.6E3.
TROPICAL CYCLONE 18S IS MOVING WEST-SOUTHWESTWARD AT 09 KNOTS. THIS
SYSTEM HAS DEVELOPED CENTRAL CONVECTION AND INTENSIFIED OVER THE
PAST 09 HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES AN
UPPER-LEVEL ANTICYCLONE IS FORMING OVER THIS DISTURBANCE, WITH
GOOD OUTFLOW IN ALL QUADRANTS EXCEPT THE EAST WHERE IT IS FAIR.
THIS SYSTEM IS CURRENTLY EXPERIENCING WEAK VERTICAL WIND SHEAR
FROM AN UPPER-LEVEL ANTICYCLONE OVER THE WESTERN HALF OF AUSTRALIA.
THE WARNING POSITION AND INTENSITY ARE BASED ON A 041730Z5 INFRARED
SATELLITE INTENSITY ESTIMATE OF 25 KNOTS AND EXTRAPOLATION FROM
040202Z8 SCATTEROMETER DATA. TROPICAL CYCLONE 18S IS FORECAST TO
MOVE SOUTHWESTWARD THROUGH 24 HOURS UNDER THE STEERING INFLUENCE OF
A MID-LEVEL RIDGE TO ITS SOUTH. AFTER 24 HOURS THIS SYSTEM IS
EXPECTED TO TRACK MORE WEST-SOUTHWESTWARD AS THE MID-LEVEL RIDGE
TO THE SOUTH STRENGTHENS. TC 18S IS FORECAST TO INTENSIFY STEADILY
IN FAVORABLE ENVIRONMENTAL CONDITIONS AND DECREASING VERTICAL WIND
SHEAR. WIND RADII ARE BASED ON EXTRAPOLATION FROM THE 040202Z8
SCATTEROMETER PASS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 041800Z3 IS
14 FEET. REFER TO WWIO30 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION.
THIS WARNING SUPERSEDES AND CANCELS NAVPACMETOCCEN 040255Z FEB 99
TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 040300). FUTURE
WARNINGS WILL BE PROVIDED 06-HOURLY UNTIL FURTHER NOTICE. NEXT
WARNINGS AT 050300Z8 (DTG 050155Z6), 050900Z4 (DTG 050755Z2),
051500Z1 (DTG 051355Z9) AND 052100Z8 (DTG 051955Z5). REFER TO
TROPICAL CYCLONE 01B WARNING (WTIO31 PGTW) FOR THE FINAL WARNING ON
THIS SYSTEM.//
=========================================================================
WTXS31 PGTW 990205 03:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 002
01 ACTIVE TROPICAL CAHWE=MISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
050000Z5 --- NEAR 18.5S4 115.7E4
MOVEMENT PAST SIX HOURS - 235 DEGREES AT 07 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
REPEAT POSIT: 18.5S4 115.7E4
---
FORECASTS:
12 HRS, VALID AT:
051200Z8 --- 19.2S2 114.3E9
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 175 NM SOUTHEAST SEMICIRCLE
OVER WATER
145 NM ELSEWHERE
VECTOR TO 24 HR POSIT: 250 DEG/ 07 KTS
---
24 HRS, VALID AT:
060000Z6 --- 19.7S7 112.9E3
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 185 NM SOUTHEAST SEMICIRCLE
OVER WATER
155 NM ELSEWHERE
VECTOR TO 36 HR POSIT: 260 DEG/ 07 KTS
---
36 HRS, VALID AT:
061200Z9 --- 20.0S2 111.4E7
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
RADIUS OF 050 KT WINDS - 025 NM
RADIUS OF 035 KT WINDS - 195 NM SOUTHEAST SEMICIRCLE
165 NM ELSEWHERE
VECTOR TO 48 HR POSIT: 260 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
070000Z7 --- 20.2S4 109.9E9
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
RADIUS OF 050 KT WINDS - 040 NM SOUTH SEMICIRCLE
025 NM ELSEWHERE
RADIUS OF 035 KT WINDS - 210 NM SOUTH SEMICIRCLE
175 NM ELSEWHERE
VECTOR TO 72 HR POSIT: 265 DEG/ 07 KTS
---
72 HRS, VALID AT:
080000Z8 --- 20.4S6 106.8E5
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
RADIUS OF 050 KT WINDS - 045 NM SOUTH SEMICIRCLE
030 NM ELSEWHERE
RADIUS OF 035 KT WINDS - 230 NM SOUTH SEMICIRCLE
180 NM ELSEWHERE
---
REMARKS:
050300Z8 POSITION NEAR 18.7S6 115.4E1.
TROPICAL CYCLONE IS MOVING SOUTHWESTWARD AT 07 KNOTS NORTH OF BARROW
ISLAND IN THE SOUTHERN INDIAN OCEAN. ANIMATED INFRARED SATELLITE
IMAGERY INDICATES DEEP CONVECTION HAS BECOME SLIGHTLY ELONGATED AND
VERTICAL SHEAR HAS INCREASED OVER THE PAST 06 HOURS. VISIBLE
SATELLITE IMAGERY SUGGESTS A PARTLY EXPOSED LOW-LEVEL CIRCULATION
CENTER JUST EAST OF THE MAIN DEEP CONVECTION. THE WARNING POSITION
AND INTENSITY ARE BASED ON 042330Z2 VISIBLE AND INFRARED SATELLITE
INTENSITY ESTIMATES OF 30 KNOTS. THERE IS NO SIGNIFICANT CHANGE TO
PREVIOUS FORECAST REASONING. TROPICAL CYCLONE 18S IS EXPECTED TO
TRACK GENERALLY WEST-SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF
THE WEAK SUB-TROPICAL RIDGE TO ITS SOUTH. THIS SYSTEM IS EXPECTED TO
INTENSIFY AS IT MOVES WEST AND VERTICAL WIND SHEAR DECREASES.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 050000Z5 IS 15 FEET. REFER TO
WWIO30 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT
050900Z4 (DTG 050755Z2), 051500Z1 (DTG 051355Z9), 052100Z8 (DTG
051955Z5) AND 060300Z9 (DTG 060155Z7).//
=========================================================================
WTXS31 PGTW 990205 09:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 003
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
050600Z1 --- NEAR 19.2S2 113.8E3
MOVEMENT PAST SIX HOURS - 250 DEGREES AT 14 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
REPEAT POSIT: 19.2S2 113.8E3
---
FORECASTS:
12 HRS, VALID AT:
051800Z4 --- 19.9S9 111.8E1
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 160 NM SOUTHEAST SEMICIRCLE
130 NM ELSEWHERE
VECTOR TO 24 HR POSIT: 250 DEG/ 10 KTS
---
24 HRS, VALID AT:
060600Z2 --- 20.6S8 109.9E9
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 175 NM SOUTHEAST SEMICIRCLE
145 NM ELSEWHERE
VECTOR TO 36 HR POSIT: 255 DEG/ 09 KTS
---
36 HRS, VALID AT:
061800Z5 --- 21.0S3 108.0E9
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 180 NM SOUTHEAST SEMICIRCLE
150 NM ELSEWHERE
VECTOR TO 48 HR POSIT: 265 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
070600Z3 --- 21.1S4 106.1E8
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
RADIUS OF 050 KT WINDS - 030 NM SOUTH SEMICIRCLE
020 NM ELSEWHERE
RADIUS OF 035 KT WINDS - 200 NM SOUTH SEMICIRCLE
165 NM ELSEWHERE
VECTOR TO 72 HR POSIT: 275 DEG/ 08 KTS
---
72 HRS, VALID AT:
080600Z4 --- 20.8S0 102.9E2
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
RADIUS OF 050 KT WINDS - 040 NM SOUTH SEMICIRCLE
025 NM ELSEWHERE
RADIUS OF 035 KT WINDS - 215 NM SOUTH SEMICIRCLE
180 NM ELSEWHERE
---
REMARKS:
050900Z4 POSITION NEAR 19.4S4 113.3E8.
TROPICAL CYCLONE 18S IS MOVING WEST-SOUTHWESTWARD AT 14 KNOTS NORTH
OF EXMOUTH GULF, THE NORTHWEST CAPE OF AUSTRALIA. THE WARNING
POSITION AND INTENSITY ARE BASED ON 050530Z3 VISIBLE AND INFRARED
SATELLITE IMAGERY WITH CURRENT INTENSITY ESTIMATES OF 30 KNOTS.
ANIMATED INFRARED AND VISIBLE SATELLITE IMAGERY INDICATES DEEP
CONVECTION HAS BECOME SEPARATED FROM THE LOW LEVEL CIRCULATION
CENTER AS VERTICAL WIND SHEAR HAS INCREASED OVER THE PAST 06 HOURS.
VISIBLE SATELLITE IMAGERY SUGGESTS A FULLY EXPOSED, BROAD LOW-LEVEL
CIRCULATION CENTER JUST EAST OF THE DEEP CONVECTION. TROPICAL
CYCLONE 18S IS EXPECTED TO TRACK GENERALLY WEST-SOUTHWESTWARD UNDER
THE STEERING INFLUENCE OF THE WEAK SUB-TROPICAL RIDGE TO ITS SOUTH.
THIS SYSTEM IS EXPECTED TO INTENSIFY SLOWLY AS IT MOVES WESTWARD AND
THE VERTICAL WIND SHEAR INCREASES. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 050600Z IS 15 FEET. NEXT WARNINGS AT 051500Z1 (DTG 051355Z9),
052100Z8 (DTG 051955Z5),060300Z9 (DTG 060155Z7) AND 060900Z5 (DTG
060755Z3).//
=========================================================================
WTXS31 PGTW 990205 15:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 004
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
051200Z8 --- NEAR 19.3S3 112.7E1
MOVEMENT PAST SIX HOURS - 265 DEGREES AT 10 KTS
POSITION ACCURATE TO WITHIN 090 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
REPEAT POSIT: 19.3S3 112.7E1
---
FORECASTS:
12 HRS, VALID AT:
060000Z6 --- 19.7S7 110.3E5
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
VECTOR TO 24 HR POSIT: 265 DEG/ 10 KTS
---
24 HRS, VALID AT:
061200Z9 --- 19.8S8 108.2E1
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 110 NM SOUTHWEST SEMICIRCLE
080 NM ELSEWHERE
VECTOR TO 36 HR POSIT: 270 DEG/ 10 KTS
---
36 HRS, VALID AT:
070000Z7 --- 19.8S8 106.0E7
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 120 NM SOUTHWEST SEMICIRCLE
090 NM ELSEWHERE
VECTOR TO 48 HR POSIT: 275 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
071200Z0 --- 19.6S6 103.9E3
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 140 NM SOUTHWEST SEMICIRCLE
100 NM ELSEWHERE
VECTOR TO 72 HR POSIT: 275 DEG/ 10 KTS
---
72 HRS, VALID AT:
081200Z1 --- 19.2S2 99.5E3
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 035 KT WINDS - 130 NM SOUTHWEST SEMICIRCLE
095 NM ELSEWHERE
---
REMARKS:
051500Z1 POSITION NEAR 19.4S4 112.1E5.
TROPICAL CYCLONE 18S IS MOVING WESTWARD AT 10 KNOTS NORTH OF
NORTHWEST CAPE, AUSTRALIA. THE WARNING POSITION AND INTENSITY ARE
BASED ON 051130Z0 INFRARED SATELLITE IMAGERY WITH CURRENT INTENSITY
ESTIMATES OF 30 KNOTS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES
FAIR CONVECTION TO THE WEST AND STRONG VERTICAL WIND SHEAR OVER THE
PAST 06 HOURS. THE LOW LEVEL CIRCULATION CENTER HAS BECOME OBSCURED
BY CIRRUS BEING SHEARED OFF OF THE CUMULUS CLOUDS TOWARDS THE
SOUTHEAST. TROPICAL CYCLONE 18S IS EXPECTED TO TRACK GENERALLY
WESTWARD UNDER THE STEERING INFLUENCE OF THE SUB-TROPICAL RIDGE TO
ITS SOUTH. THIS SYSTEM IS EXPECTED TO INTENSIFY SLOWLY AS IT MOVES
WESTWARD THEN BEGIN TO WEAKEN AT 72 HOURS. VERTICAL WIND SHEAR
ASSOCIATED WITH SOUTHEASTERLY SURFACE WINDS AND THE UPPER-LEVEL
NORTHWEST FLOW IS NOT EXPECTED TO WEAKEN THROUGH THE FORECAST
PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051200Z IS 15 FEET. NEXT
WARNINGS AT 052100Z8 (DTG 051955Z5),060300Z9 (DTG 060155Z7),
060900Z5 (DTG 060755Z3) AND 061500Z2 (DTG 061355Z0).//
=========================================================================
WTXS31 PGTW 990205 21:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 005
01 ACTIVE TROPICAL CT?RHWE=MISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
051800Z4 --- NEAR 19.1S1 112.5E9
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 - 035 KT, GUSTS 045 KT
REPEAT POSIT: 19.1S1 112.5E9
---
FORECASTS:
12 HRS, VALID AT:
060600Z2 --- 19.2S2 111.2E5
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
VECTOR TO 24 HR POSIT: 255 DEG/ 07 KTS
---
24 HRS, VALID AT:
061800Z5 --- 19.6S6 109.7E7
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 110 NM SOUTH SEMICIRCLE
080 NM ELSEWHERE
VECTOR TO 36 HR POSIT: 260 DEG/ 07 KTS
---
36 HRS, VALID AT:
070600Z3 --- 19.8S8 108.2E1
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 120 NM SOUTH SEMICIRCLE
090 NM ELSEWHERE
VECTOR TO 48 HR POSIT: 265 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
071800Z6 --- 19.9S9 106.8E5
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 140 NM SOUTH SEMICIRCLE
100 NM ELSEWHERE
VECTOR TO 72 HR POSIT: 275 DEG/ 08 KTS
---
72 HRS, VALID AT:
081800Z7 --- 19.6S6 103.3E7
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 140 NM SOUTH SEMICIRCLE
100 NM ELSEWHERE
---
REMARKS:
052100Z8 POSITION NEAR 19.1S1 112.2E6.
TROPICAL CYCLONE 18S HAS MOVED WESTWARD AT 6 KNOTS OVER THE PAST 6
HOURS. THE WARNING POSITION AND INTENSITY ARE BASED ON 051730Z6
INFRARED SATELLITE IMAGERY ANALYSIS WITH CURRENT INTENSITY
ESTIMATES OF 30 AND 35 KNOTS. ANIMATED INFRARED SATELLITE IMAGERY
INDICATES INTERMITTENT CONVECTION TO THE WEST AND MODERATE TO STRONG
VERTICAL WINDSHEAR. AN EARLIER MICROWAVE PASS (051322Z3) INDICATED
THE LOW-LEVEL CIRCULATION CENTER REMAINS SHEARED TO THE EAST OF THE
CONVECTION. ANIMATED WATER VAPOR IMAGERY SHOWS TC 18S IS AT THE
TAIL-END OF A SHEARLINE THAT IS MOVING THROUGH SOUTHWESTERN
AUSTRALIA. THE STRONGER UPPER-LEVEL WINDS SUPPORTING THIS BOUNDARY
ARE CREATING THE WINDSHEAR OVER TC 18S. TROPICAL CYCLONE 18S IS
EXPECTED TO CONTINUE TO TRACK GENERALLY WESTWARD UNDER THE STEERING
INFLUENCE OF THE SUB-TROPICAL RIDGE TO ITS SOUTH. TC 18S IS EXPECTED
TO SLOWLY INTENSIFY AS IT MOVES WESTWARD OUT OF THE STRONG SHEAR
ENVIRONMENT. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051800Z4 IS 15 FEET.
REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT
WARNINGS AT 060300Z9 (DTG 060155Z7), 060900Z5 (DTG 060755Z3),
061500Z2 (DTG 061355Z0) AND 062100Z9 (DTG 061955Z6).//
=========================================================================
WTXS31 PGTW 990206 03:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 006
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
060000Z6 --- NEAR 18.8S7 111.2E5
MOVEMENT PAST SIX HOURS - 275 DEGREES AT 11 KTS
POSITION ACCURATE TO WITHIN 045 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 120 NM SOUTHWEST SEMICIRCLE
060 NM ELSEWHERE
REPEAT POSIT: 18.8S7 111.2E5
---
FORECASTS:
12 HRS, VALID AT:
061200Z9 --- 18.9S8 109.1E1
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 120 NM SOUTHWEST SEMICIRCLE
070 NM ELSEWHERE
VECTOR TO 24 HR POSIT: 265 DEG/ 09 KTS
---
24 HRS, VALID AT:
070000Z7 --- 19.1S1 107.3E1
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 130 NM SOUTHWEST SEMICIRCLE
080 NM ELSEWHERE
VECTOR TO 36 HR POSIT: 265 DEG/ 09 KTS
---
36 HRS, VALID AT:
071200Z0 --- 19.2S2 105.4E0
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 130 NM SOUTHWEST SEMICIRCLE
080 NM ELSEWHERE
VECTOR TO 48 HR POSIT: 265 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
080000Z8 --- 19.3S3 103.4E8
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
RADIUS OF 035 KT WINDS - 140 NM SOUTHWEST SEMICIRCLE
100 NM ELSEWHERE
VECTOR TO 72 HR POSIT: 270 DEG/ 09 KTS
---
72 HRS, VALID AT:
090000Z9 --- 19.3S3 99.7E5
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
RADIUS OF 035 KT WINDS - 140 NM SOUTHWEST SEMICIRCLE
100 NM ELSEWHERE
---
REMARKS:
060300Z9 POSITION NEAR 18.8S7 110.7E9.
TROPICAL CYCLONE 18S HAS MOVED WESTWARD AT 11 KNOTS OVER THE PAST 6
HOURS. THE WARNING POSITION WAS BASED ON 052330Z3 VISIBLE SATELLITE
IMAGERY ANALYSIS. THE VISIBLE IMAGERY SHOWS A FULLY EXPOSED LOW-
LEVEL CIRCULATION CENTER (LLCC). AS SUCH, THE INITIAL POSITION HAS
BEEN SHIFTED SLIGHTLY NORTH AND FORWARD SPEED INCREASED TO REFLECT
THIS MORE CONFIDENT POSITION FIX. THE WARNING INTENSITY WAS BASED ON
A COMBINATION OF 052330Z3 VISIBLE SATELLITE IMAGERY INTENSITY
ESTIMATES OF 30-35 KNOTS AND A 051537Z1 MICROWAVE SCATTEROMETER
PASS. THE SCATTEROMETER PASS INDICATED 35 KNOT WINDS EXTENDING OUT
ABOUT 120NM SOUTHWEST OF THE LLCC. ANIMATED SATELLITE IMAGERY SHOWS
INTERMITTENT CONVECTION TO THE SOUTH-WEST AND MODERATE VERTICAL
WINDSHEAR. VISIBLE IMAGERY AND THE SCATTEROMETER PASS INDICATE THE
CONVECTION IS SHEARED ABOUT 90NM SOUTHWEST OF THE LLCC. TROPICAL
CYCLONE 18S IS EXPECTED TO CONTINUE TO TRACK WESTWARD UNDER THE
STEERING INFLUENCE OF THE SUB-TROPICAL RIDGE TO ITS SOUTH. TC 18S IS
EXPECTED TO SLOWLY INTENSIFY AS IT MOVES WESTWARD OUT OF THE
STRONGER SHEAR ENVIRONMENT. THE WIND RADII WERE EXTENDED
SOUTHWESTWARD TO REFLECT THE SCATTEROMETER DATA. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 060000Z6 IS 15 FEET. REFER TO WWIO30 PGFW FOR
ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 060900Z5 (DTG
060755Z3), 061500Z2 (DTG 061355Z0), 062100Z9 (DTG 061955Z6) AND
070300Z0 (DTG 070155Z8).//
=========================================================================
WTXS31 PGTW 990206 09:00z
1. TROPICAL CYCLONE 18S WARNING NR 007
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
060600Z2 --- NEAR 18.4S3 110.3E5
MOVEMENT PAST SIX HOURS - 295 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 120 NM SOUTHWEST SEMICIRCLE
060 NM ELSEWHERE
REPEAT POSIT: 18.4S3 110.3E5
---
FORECASTS:
12 HRS, VALID AT:
061800Z5 --- 17.9S7 109.2E2
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 120 NM SOUTHWEST SEMICIRCLE
060 NM ELSEWHERE
VECTOR TO 24 HR POSIT: 270 DEG/ 06 KTS
---
24 HRS, VALID AT:
070600Z3 --- 17.9S7 107.9E7
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 120 NM SOUTHWEST SEMICIRCLE
060 NM ELSEWHERE
VECTOR TO 36 HR POSIT: 265 DEG/ 08 KTS
---
36 HRS, VALID AT:
071800Z6 --- 18.0S9 106.3E0
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 130 NM SOUTHWEST SEMICIRCLE
070 NM ELSEWHERE
VECTOR TO 48 HR POSIT: 265 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
080600Z4 --- 18.1S0 104.5E0
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 130 NM SOUTH SEMICIRCLE
070 NM ELSEWHERE
VECTOR TO 72 HR POSIT: 270 DEG/ 09 KTS
---
72 HRS, VALID AT:
090600Z5 --- 18.2S1 100.9E0
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 130 NM SOUTH SEMICIRCLE
070 NM ELSEWHERE
---
REMARKS:
060900Z5 POSITION NEAR 18.3S2 110.0E2.
TROPICAL CYCLONE 18S HAS TRACKED TOWARDS THE WEST-NORTHWEST AT 9
KNOTS DURING THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON
060530Z4 VISIBLE SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED
ON SATELLITE CURRENT INTENSITY ESTIMATES AND A 051534Z8
SCATTEROMETER PASS REFLECTING A MINIMUM OF 35 KNOTS WITH A
SOUTHWESTWARDLY DISPLACED LOW LEVEL WINDFIELD. TC 18S HAS CONTINUED
TO MOVE UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE TO THE
SOUTH. SINCE THE LOW LEVEL CIRCULATION IS FULLY EXPOSED AND SHEARED
EAST FROM THE SIGNIFICANT CONVECTION, THE SYSTEM HAS ENCOUNTERED
WEAKER STEERING FLOW FROM THE LOW TO MID LEVELS OF THE ATMOSPHERE.
TC 18S IS FORECAST TO SLOW WHILE CONTINUING TO TRACK WEST-
NORTHWESTWARD DURING THE INITIAL 12 HOURS OF THE FORECAST. THE
SYSTEMS IS EXPECTED TO RETURN TO MORE OF A WESTWARD TRACK AFTER THE
12 HOUR POSITION AND THROUGHOUT THE REMAINDER OF THE 72 HOUR
FORECAST PERIOD. DUE TO MODERATE SHEAR AND FAIR OUTFLOW ALOFT, THE
SYSTEM IS NOT FORECAST TO INCREASE INTENSITY DURING THE FIRST 36
HOURS. AFTERWARDS, THE SYSTEM IS EXPECTED TO INTENSIFY SLIGHTLY
UNDER CONDITIONS OF DECREASING SHEAR AND IMPROVED OUTFLOW. AN
ALTERNATE SCENARIO WOULD INVOLVE WEAKER STEERING FLOW CAUSING AN
EVEN SLOWER FORWARD SPEED AND POSSIBLY A SHORT TERM CYCLONINC TURN
IN THE TRACK. AFTERWARDS, THE SYSTEM WOULD AGAIN TRACK TOWARDS THE
WEST AS CURRENTLY FORECASTED. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
060600Z IS 15 FEET. REFER TO WWIO30 PGFW FOR ADDITIONAL SEA HEIGHT
INFORMATION. NEXT WARNINGS AT 061500Z2 (DTG 061355Z0), 062100Z9 (DTG
061955Z6), 070300Z0 (DTG 070155Z8) AND 070900Z6 (DTG 070755Z4).
=========================================================================
WTXS31 PGTW 990206 15:00z
1. TROPICAL CYCLONE 18S WARNING NR 008
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
061200Z9 --- NEAR 18.2S1 109.5E5
MOVEMENT PAST SIX HOURS - 285 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 100 NM SOUTHWEST SEMICIRCLE
090 NM ELSEWHERE
REPEAT POSIT: 18.2S1 109.5E5
---
FORECASTS:
12 HRS, VALID AT:
070000Z7 --- 18.0S9 108.0E9
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 100 NM SOUTHWEST SEMICIRCLE
090 NM ELSEWHERE
VECTOR TO 24 HR POSIT: 270 DEG/ 07 KTS
---
24 HRS, VALID AT:
071200Z0 --- 18.0S9 106.5E2
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 100 NM SOUTHWEST SEMICIRCLE
090 NM ELSEWHERE
VECTOR TO 36 HR POSIT: 265 DEG/ 09 KTS
---
36 HRS, VALID AT:
080000Z8 --- 18.1S0 104.7E2
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 110 NM SOUTHWEST SEMICIRCLE
100 NM ELSEWHERE
VECTOR TO 48 HR POSIT: 270 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
081200Z1 --- 18.1S0 102.9E2
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 110 NM SOUTH SEMICIRCLE
100 NM ELSEWHERE
VECTOR TO 72 HR POSIT: 270 DEG/ 09 KTS
---
72 HRS, VALID AT:
091200Z2 --- 18.1S0 99.2E0
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
RADIUS OF 035 KT WINDS - 110 NM SOUTH SEMICIRCLE
100 NM ELSEWHERE
---
REMARKS:
061500Z2 POSITION NEAR 18.1S0 109.1E1.
TROPICAL CYCLONE 18S HAS TRACKED TOWARDS THE WEST-NORTHWEST AT
8 KNOTS DURING THE PAST 6 HOURS. THE WARNING POSITION IS BASED
ON 061130Z1 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY
IS BASED ON A 060241Z3 SCATTEROMETER IMAGE AND EXTRAPOLATION
FROM THE PREVIOUS WARNING. TC 18S HAS CONTINUED TO TRACK UNDER
THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE TO THE SOUTH.
DUE TO SHEARING OF THE CONVECTION TO THE WEST OF THE LOW LEVEL
CIRCULATION, THE SYSTEM WAS STEERED SLIGHTLY NORTH FROM IT=S
PREVIOUS PATH. TC 18S IS FORECAST TO BEGIN TO TRACK MORE
WESTWARD AFTER THE 12-HOUR FORECAST PERIOD. THERE MAY,HOWEVER,
MAY BE SOME WOBBLE IN THE TRACK OF THE SYSTEM DUE TO SHEARING
EFFECTS. TC 18S IS FORECAST TO MAINTAIN IT=S INTENSITY THROUGH
OUT THE FIRST PORTION OF THE FORECAST PERIOD. DECREASING SHEAR
UPSTREAM MAY ALLOW SOME INTENSIFICATION AFTER THE 36 HOUR
POSITION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 061200Z IS 15
FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT
INFORMATION. NEXT WARNINGS AT 062100Z9 (DTG 061955Z6),
070300Z0 (DTG 070155Z8), 070900Z6 (DTG 070755Z4) AND 071500Z3
(DTG 071355Z1).
=========================================================================
WTXS31 PGTW 990206 21:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 009
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ONPN,)NEYRAGE
---
WARNING POSITION:
061800Z5 --- NEAR 18.3S2 108.8E7
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 300 NM SOUTHWEST QUADRANT
090 NM ELSEWHERE
REPEAT POSIT: 18.3S2 108.8E7
---
FORECASTS:
12 HRS, VALID AT:
070600Z3 --- 18.3S2 107.1E9
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 300 NM SOUTHWEST QUADRANT
090 NM ELSEWHERE
VECTOR TO 24 HR POSIT: 270 DEG/ 08 KTS
---
24 HRS, VALID AT:
071800Z6 --- 18.3S2 105.5E1
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 300 NM SOUTHWEST QUADRANT
090 NM ELSEWHERE
VECTOR TO 36 HR POSIT: 270 DEG/ 08 KTS
---
36 HRS, VALID AT:
080600Z4 --- 18.3S2 103.9E3
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 275 NM SOUTHWEST QUADRANT
080 NM ELSEWHERE
VECTOR TO 48 HR POSIT: 270 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
081800Z7 --- 18.3S2 102.3E6
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 250 NM SOUTHWEST QUADRANT
070 NM ELSEWHERE
VECTOR TO 72 HR POSIT: 270 DEG/ 08 KTS
---
72 HRS, VALID AT:
091800Z8 --- 18.2S1 99.0E8
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
RADIUS OF 035 KT WINDS - 250 NM SOUTHWEST QUADRANT
070 NM ELSEWHERE
---
REMARKS:
062100Z9 POSITION NEAR 18.3S2 108.4E3.
TROPICAL CYCLONE 18S HAS MOVED WESTWARD AT 8 KNOTS OVER THE PAST 6
HOURS. THE WARNING POSITION AND INTENSITY ARE BASED ON A
COMBINATION OF 061730Z7 INFRARED SATELLITE IMAGERY ANALYSIS WITH
CURRENT INTENSITY ESTIMATES OF 25 KNOTS, A MICROWAVE IMAGER PASS
(061310Z1), AND A PREVIOUS MICROWAVE SCATTEROMETER PASS (060241Z3).
THE SCATTEROMETER PASS INDICATED A 40 KNOT MAX WIND WITH 35 KNOT
WINDS EXTENDING 300NM SOUTHWEST. ANIMATED INFRARED SATELLITE
IMAGERY INDICATES INTERMITTENT CONVECTION REMAINING WELL WEST OF
THE LOW-LEVEL CIRCULATION CENTER (LLCC) AND MODERATE TO STRONG
VERTICAL WINDSHEAR. THE PREVIOUS MICROWAVE DATA INDICATED THE LLCC
REMAINS WELL EAST OF THE CONVECTION. TROPICAL CYCLONE 18S IS
EXPECTED TO CONTINUE TO TRACK WESTWARD UNDER THE STEERING INFLUENCE
OF THE SUB-TROPICAL RIDGE TO THE SOUTH. TC 18S IS EXPECTED TO
MAINTAIN INTENSITY AS IT MOVES WESTWARD OUT OF THE STRONGEST SHEAR
ENVIRONMENT. SHEAR IS STILL FORECAST TO REMAIN MODERATE THROUGHOUT
THE PERIOD. THE WIND RADII WAS EXTENDED SOUTHWESTWARD TO INCLUDE
THE GALE FORCE WINDS CAUSED BY THE INCREASED PRESSURE GRADIENT
BETWEEN TC 18S AND THE HIGH PRESSURE AREA SOUTH. THIS AREA IS
EXPECTED TO DECREASE AS THE SYSTEM MOVES FURTHER WESTWARD. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 061800Z5 IS 15 FEET. REFER TO WWIO31
PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT
070300Z0 (DTG 070155Z8), 070900Z6 (DTG 070755Z4), 071500Z3 (DTG
071355Z1) AND 072100Z0 (DTG 071955Z7).//
=========================================================================
WTXS31 PGTW 990207 03:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 010
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
070000Z7 --- NEAR 18.5S4 108.7E6
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
REPEAT POSIT: 18.5S4 108.7E6
---
FORECASTS:
12 HRS, VALID AT:
071200Z0 --- 18.5S4 107.9E7
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 270 DEG/ 04 KTS
---
24 HRS, VALID AT:
080000Z8 --- 18.5S4 107.0E8
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 36 HR POSIT: 270 DEG/ 05 KTS
---
36 HRS, VALID AT:
081200Z1 --- 18.5S4 106.0E7
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 48 HR POSIT: 270 DEG/ 05 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
090000Z9 --- 18.5S4 105.0E6
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
070300Z0 POSITION NEAR 18.5S4 108.5E4.
TROPICAL CYCLONE 18S HAS MOVED SLOWLY WESTWARD AT 3 KNOTS OVER THE
PAST 6 HOURS. THE WARNING POSITION AND INTENSITY (35 KNOTS) ARE
BASED ON A COMBINATION OF 062330Z4 VISIBLE SATELLITE IMAGERY
ANALYSIS (25 KNOTS), A PREVIOUS SCATTEROMETER PASS (40 KTS), AND A
TROPICAL RAINFALL MEASUREMENT MISSION (TRMM) MICROWAVE IMAGER PASS
(061810Z6). ANIMATED SATELLITE IMAGERY INDICATES DIMINISHING
CONVECTION AND STRONG VERTICAL WINDSHEAR. MICROWAVE AND VISIBLE
SATELLITE DATA INDICATE THE LOW-LEVEL CIRCULATION CENTER REMAINS
FULLY EXPOSED AND WELL EAST OF THE CONVECTION. IMAGERY ALSO SHOWS
TC 18S HAS WEAKENED OVER THE PAST 6 HOURS AND HAS BECOME BROAD AND
ELONGATED. TROPICAL CYCLONE 18S IS EXPECTED TO CONTINUE TO TRACK
WESTWARD UNDER THE STEERING INFLUENCE OF THE SUB-TROPICAL RIDGE TO
THE SOUTH. TC 18S IS EXPECTED TO SLOWLY WEAKEN AS MODERATE
TO STRONG VERTICAL WINDSHEAR CONTINUES OVER THE FORECAST TRACK. TC
18S IS FORECAST TO DISSIPATE AS A SIGNIFICANT TROPICAL CYCLONE BY
THE 48 HOUR POSITION. THE WIND RADII IS OMITTED FOR INTENSITIES OF
35 KNOTS OR LESS. EVEN SO, DATA INDICATES AN EXTENSIVE AREA OF 25-
30KT WINDS EXTENDS SOUTHWESTWARD CAUSED BY A STRONG PRESSURE
GRADIENT BETWEEN TC 18S AND THE HIGH PRESSURE AREA SOUTH. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 070000ZZ7 IS 15 FEET. REFER TO WWIO30
PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT
070900Z6 (DTG 070755Z4), 071500Z3 (DTG 071355Z1), 072100Z0 (DTG
071955Z7) AND 080300Z1 (DTG 080155Z9).//
=========================================================================
WTXS31 PGTW 990207 09:00z
1. TROPICAL CYCLONE 18S WARNING NR 011
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
070600Z3 --- NEAR 18.6S5 108.6E5
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
REPEAT POSIT: 18.6S5 108.6E5
---
FORECASTS:
12 HRS, VALID AT:
071800Z6 --- 18.7S6 108.0E9
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 265 DEG/ 05 KTS
---
24 HRS, VALID AT:
080600Z4 --- 18.8S7 107.0E8
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 36 HR POSIT: 280 DEG/ 06 KTS
---
36 HRS, VALID AT:
081800Z7 --- 18.6S5 105.7E3
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 48 HR POSIT: 275 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
090600Z5 --- 18.5S4 104.1E6
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
070900Z6 POSITION NEAR 18.6S5 108.5E4.
TROPICAL CYCLONE 18S HAS DRIFTED TOWARDS THE WEST AT 3 KNOTS
DURING THE PAST 6 HOURS. THE FORECAST POSITION IS BASED ON
070530Z5 VISIBLE SATELLITE IMAGERY. THE WARNING INTENSITY IS
BASED ON AN EXTRAPOLATION FROM THE PREVIOUS WARNING AND ESTIMATED
CLOUD DRIFT WIND SPEED. TC 18S HAS REMAINED FULLY EXPOSED WITH A
SIGNIFICANT LOW LEVEL WIND FIELD. MOST OF THE CONVECTION
ASSOCIATED WITH THE SYSTEM HAS DISSIPATED. TC 18S HAS ENTERED A
REGION OF WEAK STEERING FLOW WITHIN A WEAKNESS IN THE SUBTROPICAL
RIDGE TO THE SOUTH. THE SYSTEM IS FORECAST TO DRIFT SLOWLY
WESTWARD WITHIN THIS WEAK FLOW DURING THE FIRST 12 HOURS, THEN
BEGIN TO ACCELERATE WESTWARD AS STRONGER FLOW BEGINS TO ONCE
AGAIN STEER THE SYSTEM THROUGHOUT THE REMAINDER OF THE FORECAST
PERIOD. TC 18S HAS CONTINUED TO REMAIN SHEARED WHILE ENTRAINING
COLD AIR STRATUS FROM THE SOUTH. THE SYSTEM IS FORECAST TO
CONINUE TO WEAKEN WHILE RETAINING A DEFINABLE LOW LEVEL WIND
FIELD. TC 18S IS FORECAST TO DISSIPATE OVER WATER BY THE 48 HOUR
FORECAST POSITION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070600Z IS
15 FEET. REFER TO WWIO30 PGFW FOR ADDITIONAL SEA HEIGHT
INFORMATION. NEXT WARNINGS AT 071500Z3 (DTG 071355Z1), 072100Z0
(DTG 071955Z7), 080300Z1 (DTG 080155Z9) AND 080900Z7 (DTG 80755Z5).
=========================================================================
WTXS31 PGTW 990207 15:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 012
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
071200Z0 --- NEAR 18.6S5 108.6E5
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
REPEAT POSIT: 18.6S5 108.6E5
---
FORECASTS:
12 HRS, VALID AT:
080000Z8 --- 18.8S7 108.2E1
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 260 DEG/ 04 KTS
---
24 HRS, VALID AT:
081200Z1 --- 18.9S8 107.4E2
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 36 HR POSIT: 275 DEG/ 08 KTS
---
36 HRS, VALID AT:
090000Z9 --- 18.8S7 105.8E4
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
071500Z3 POSITION NEAR 18.6S5 108.5E4.
TROPICAL CYCLONE 18S HAS REMAINED QUASI-STATIONARY DURING THE PAST
6 HOURS. THE WARNING POSITION IS BASED ON 071130Z2 ENHANCED INFRARED
IMAGERY. THE WARNING INTENSITY IS BASED ON EXTRAPOLATION FROM THE
PREVIOUS WARNING AND ESTIMATED CLOUD DRIFT WIND SPEEDS. TC 18S
HAS REMAINED WITHIN VERY WEAK STEERING FLOW BETWEEN TWO LOW-MID
LEVEL SUBTROPICAL RIDGES TO THE SOUTHEAST AND SOUTHWEST. THIS WEAK
STEERING FLOW CAN ALLOW FOR SOME SHORT TERM ERRATIC MOVEMENTS IN
THE SYSTEMS TRACK. TC 18S IS FORECAST TO REMAIN QUASI-STATIONARY
WITH A SLIGHT SOUTHWESTWARD DRIFT DURING THE FIRST 12 HOURS. THE
SYSTEM IS EXPECTED TO EVENTUALLY RETURN TO A WESTWARD TRACK BETWEEN
THE 12 TO 24 HOUR PERIOD AS THE SUBTROPICAL RIDGE TO THE SOUTHWEST
SLOWLY BUILDS EAST AND INCREASES STEERING FLOW ON THE SYSTEM.
CONTINUED SHEAR AND COLD AIR STRATUS ENTRAINMENT IS EXPECTED TO
INHIBIT FURTHER DEVELOPMENT OF THE SYSTEM. TC 18S IS FORECAST TO
CONTINUE TO DISSIPATE OVER WATER, FINALLY DISSIPATING COMPLETELY
BY THE 36 HOUR FORECAST POSITION. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 071200Z IS 14 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA
HEIGHT INFORMATION. NEXT WARNINGS AT 080300Z1 (DTG 080155Z9) AND
081500Z4 (DTG 081355Z2).//
=========================================================================
WTXS31 PGTW 990207 21:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 013
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
071800Z6 --- NEAR 19.1S1 108.3E2
MOVEMENT PAST SIX HOURS - 235 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
REPEAT POSIT: 19.1S1 108.3E2
---
FORECASTS:
12 HRS, VALID AT:
080600Z4 --- 19.2S2 108.0E9
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 250 DEG/ 02 KTS
---
24 HRS, VALID AT:
081800Z7 --- 19.3S3 107.7E5
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 36 HR POSIT: 250 DEG/ 02 KTS
---
36 HRS, VALID AT:
090600Z5 --- 19.4S4 107.4E2
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
072100Z0 POSITION NEAR 19.1S1 108.2E1.
TROPICAL CYCLONE 18S HAS DRIFTED SOUTHWESTWARD OVER THE PAST
6 HOURS. THE WARNING POSITION IS BASED ON A COMBINATION OF 071730Z8
ENHANCED INFRARED IMAGERY AND A MICROWAVE IMAGERY
WARNING AND EARLIER ESTIMATES OF LOW-LEVEL CLOUD DRIFT WIND SPEEDS.
TC 18S REMAINS WITHIN THE WEAK STEERING FLOW OF THE BROADER MONSOON
TROUGH AND THE SUBTROPICAL RIDGE TO THE SOUTHEAST. TC 18S IS
FORECAST TO CONTINUE DRIFTING SOUTHWESTWARD THROUGH 24 HOURS.
AFTERWARDS, TC18S IS EXPECTED TO TURN MORE WESTWARD AS THE
SUBTROPICAL RIDGE TO THE SOUTHEAST BUILDS WESTWARD UNDER THE
SYSTEM. CONTINUED SHEAR AND COOLER LOW-LEVEL ENTRAINMENT IS
EXPECTED TO INHIBIT FURTHER DEVELOPMENT OF THE SYSTEM. TC 18S IS
FORECAST TO DISSIPATE OVER WATER BY THE 36 HOUR FORECAST POSITION.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 071800Z6 IS 14 FEET. REFER TO
WWIO31 PGFW FOR ADDITIO>M SEA HEIGHT INFORMATION. NEXT WARNINGS AT
080300Z1 (DTG 0801U5Z9), 080900Z7 (DTG 080755Z5), 081500Z4 (DTG
081355Z2) AND 0Z1 (DTG 081955Z8).//
=========================================================================
WTXS31 PGTW 990208 03:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 014
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
080000Z8 --- NEAR 19.1S1 107.8E6
MOVEMENT PAST SIX HOURS - 255 DEGREES AT 04 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
REPEAT POSIT: 19.1S1 107.8E6
---
FORECASTS:
12 HRS, VALID AT:
081200Z1 --- 19.3S3 107.2E0
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
VECTOR TO 24 HR POSIT: 260 DEG/ 03 KTS
---
24 HRS, VALID AT:
090000Z9 --- 19.4S4 106.6E3
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 36 HR POSIT: 270 DEG/ 03 KTS
---
36 HRS, VALID AT:
091200Z2 --- 19.4S4 106.0E7
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
080300Z1 POSITION NEAR 19.1S1 107.6E4.
TROPICAL CYCLONE 18S HAS DRIFTED SOUTHWESTWARD OVER THE PAST
6 HOURS. THE WARNING POSITION IS BASED ON 072330Z5 VISIBLE IMAGERY
ANALYSIS. THE WARNING INTENSITY IS BASED ON EXTRAPOLATION FROM THE
PREVIOUS WARNING AND ESTIMATES OF LOW-LEVEL CLOUD DRIFT WIND
SPEEDS. VISIBLE IMAGERY REVEALS A WELL-DEFINED AND FULLY EXPOSED
LOW-LEVEL CIRCULATION CENTER (LLCC). ANIMATED IMAGERY ALSO SHOWS
LIMITED CONVECTION HAS REDEVELOPED NORTHWEST OF THE LLCC OVER THE
PAST 6 HOURS. IMAGERY ALSO SHOWS AN EXTENSIVE STRATOCUMULUS DECK
ABOUT 150NM SOUTHWEST OF THE LLCC MOVING NORTHWARD INTO THE
CIRCULATION. TC 18S REMAINS WITHIN THE WEAK STEERING FLOW OF THE
BROADER MONSOON TROUGH AND THE SUBTROPICAL RIDGE TO THE SOUTHEAST.
TC 18S IS FORECAST TO CONTINUE DRIFTING SOUTHWESTWARD THROUGH 24
HOURS. AFTERWARDS, TC 18S IS EXPECTED TO TURN MORE WESTWARD AS
THE SUBTROPICAL RIDGE BUILDS SOUTH OF THE SYSTEM. CONTINUED
SHEAR AND COOLER LOW-LEVEL TEMPERATURE ENTRAINMENT IS EXPECTED
TO INHIBIT FURTHER DEVELOPMENT OF THE SYSTEM. TC 18S IS FORECAST
TO DISSIPATE OVER WATER BY THE 36 HOUR FORECAST POSITION. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 080000Z8 IS 14 FEET. REFER TO WWIO30
PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT
080900Z7 (DTG 080755Z5), 081500Z4 (DTG 081355Z2), 082100Z1
(DTG 081955Z8) AND 090300Z2 (DTG 090155Z0).//
=========================================================================
WTXS31 PGTW 990208 09:00z
1. TROPICAL CYCLONE 18S WARNING NR 015
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
080600Z4 --- NEAR 19.0S0 107.6E4
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
REPEAT POSIT: 19.0S0 107.6E4
---
FORECASTS:
12 HRS, VALID AT:
081800Z7 --- 19.1S1 107.0E8
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 270 DEG/ 04 KTS
---
24 HRS, VALID AT:
090600Z5 --- 19.1S1 106.2E9
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 36 HR POSIT: 275 DEG/ 05 KTS
---
36 HRS, VALID AT:
091800Z8 --- 19.0S0 105.1E7
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
080900Z7 POSITION NEAR 19.0S0 107.5E3.
TROPICAL CYCLONE 18S HAS DRIFTED WESTWARD AT 3 KNOTS OVER THE PAST
6 HOURS. THE WARNING POSITION AND INTENSITY IS BASED ON 080530Z6
VISIBLE SATELLITE IMAGERY, LOW LEVEL CLOUD DRIFT WIND SPEED, AND
EXTRAPOLATION FROM THE PREVIOUS WARNING. TC 18S REMAINS WITHIN THE
WEAK STEERING FLOW OF THE MONSOON TROUGH AND A BROAD WEAKNESS IN THE
SUBTROPICAL RIDGE TO THE SOUTH. THERE APPEARS TO BE NO SIGNIFICANT
CONVECTION ASSOCIATED WITH THE SYSTEMS, THOUGH THE LOW LEVEL WINDS
STILL REMAIN SIGNIFICANT. THE FULLY EXPOSED LOW LEVEL CIRCULATION
HAS CONTINUED TO BROADEN AND WEAKEN. TC 18S IS FORECAST TO CONTINUE
TO DRIFT TOWARDS THE WEST, EVENTUALLY RETURNING TO A STRONGER
WESTWARD STEERING FLOW BETWEEN THE 12 TO 24 HOUR FORECAST PERIOD.
MIXING WITH COLD AIR STRATUS AND ABUNDANT MID TO UPPER LEVEL SHEAR
IS FORECASTED CAUSE THE SYSTEM TO CONTINUE TO SLOWLY WEAKEN AND
FINALLY DISSIPATE OVER WATER BY THE 36 HOUR FORECAST PERIOD. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 080600Z IS 14 FEET. REFER TO WWIO30 PGFW
FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 081500Z4
(DTG 081355Z2), 082100Z1 (DTG 081955Z8), 090300Z2 (DTG 090155Z0)
AND 090900Z8 (DTG 090755Z6).
=========================================================================
WTXS31 PGTW 990208 15:00z
1. TROPICAL CYCLONE 18S WARNING NR 016
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
081200Z1 --- NEAR 19.0S0 107.3E1
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
REPEAT POSIT: 19.0S0 107.3E1
---
FORECASTS:
12 HRS, VALID AT:
090000Z9 --- 19.0S0 106.7E4
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 270 DEG/ 04 KTS
---
24 HRS, VALID AT:
091200Z2 --- 19.0S0 105.8E4
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 36 HR POSIT: 280 DEG/ 07 KTS
---
36 HRS, VALID AT:
100000Z1 --- 18.8S7 104.3E8
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
081500Z4 POSITION NEAR 19.0S0 107.1E9.
TROPICAL CYCLONE 18S HAS DRIFTED TOWARDS THE WEST AT 3 KNOTS OVER
THE PAST 6 HOURS. THE WARNING POSITION AND INTENSITY IS BASED ON
081130Z3 ANIMATED INFRARED SATELLITE IMAGERY AND EXTRAPOLATION
FROM THE PREVI0US WARNING. TC 18S REMAINS WITHIN THE WEAK STEERING
FLOW OF THE MONSOON TROUGH NEAR A BROAD WEAKNESS IN THE SUBTROPICAL
RIDGE TO THE SOUTH. TC 18S IS FORECAST TO CONTINUE TO DRIFT TOWARDS
THE WEST, EVENTUALLY RETURNING TO A STRONGER WESTWARD STEERING FLOW
BETWEEN THE 12 AND 24 HOUR FORECAST PERIOD. TC 18S HAS RECENTLY
DEVELOPED CONVECTION ACROSS THE NORTHWEST QUADRANT OF THE FULLY
EXPOSED LOW LEVEL CIRCULATION. MODERATE WESTWARD SHEAR AND COLD AIR
STRATUS MIXING FROM THE SOUTH, HOWEVER, CONTINUES TO INHIBIT
NOTABLE DEVELOPMENT. CONVECTIVE DEVELOPMENT DURING THE PAST 36
HOURS HAS ONLY BEEN SPORADIC AND SHORT LIVED. THE LOW LEVEL WIND
FIELD ASSOCIATED WITH THE SYSTEM HAS CONTINUED TO BROADEN BUT
REMAINS SIGNIFICANT. TC 18S IS FORECAST TO MAINTAIN ITS CURRENT
INTENSITY DURING THE FIRST 12 HOURS, THEN SLOWLY DISSIPATE OVER
WATER BY THE 36 HOUR FORECAST PERIOD. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 081200Z IS 14 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL
SEA HEIGHT INFORMATION. NEXT WARNINGS AT 082100Z1 (DTG 081955Z8),
090300Z2 (DTG 090155Z0), 090900Z8 (DTG 090755Z6) AND 091500Z5
(DTG 091355Z3).
=========================================================================
WARNING 017 NOT AVAILABLE
=========================================================================
WTXS31 PGTW 990209 03:00z
SUBJ: TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 18S WARNING NR 018
01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
090000Z9 --- NEAR 18.5S4 107.6E4
MOVEMENT PAST SIX HOURS - 360 DEGREES AT 01 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
REPEAT POSIT: 18.5S4 107.6E4
---
FORECASTS:
12 HRS, VALID AT:
091200Z2 --- 18.1S0 107.4E2
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 295 DEG/ 04 KTS
---
24 HRS, VALID AT:
100000Z1 --- 17.8S6 106.7E4
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
090300Z2 POSITION NEAR 18.4S3 107.6E4.
TROPICAL CYCLONE 18S IS QUASISTATIONARY IN THE SOUTH INDIAN OCEAN.
ANIMATED VISIBLE AND INFRARED SATELLITE IMAGERY INDICATE ONLY
SCATTERED CONVECTION EXISTS IN THE VICINITY OF THE FULLY EXPOSED
LOW-LEVEL CIRCULATION CENTER. 081540Z8 SCATTEROMETER DATA INDICATES
STRONGEST WINDS ARE LOCATED NORTH OF THE CIRCULATION CENTER. THE
WARNING POSITION AND INTENSITY ARE BASED ON 082330Z6 VISIBLE AND
INFRARED SATELLITE INTENSITY ESTIMATES OF 25 KNOTS. TC 18S IS
EXPECTED TO DRIFT SLOWLY NORTHWESTWARD AND DISSIPATE BY 24 HOURS
DUE TO CONTINUED VERTICAL SHEAR AND COLD AIR STRATOCUMULUS
ENTRAINMENT. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 09000Z9 IS 13 FEET.
REFER TO WWIO30 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. THIS IS
THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WARNING
CENTER (NAVPACMETOCCEN PEARL HARBOR HI). THE SYSTEM WILL BE
CLOSELY MONITORED FOR SIGNS OF REGENERATION.//
Tropical cyclone tracks developed by Michael Bath using operational warnings and advisories.
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Document: tropical_cyclone_199918_jtwc_advisories.htm
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