Subject: Indian-S: 03 Active Tropical Cyclones In Southern Hemisphere

From: SIU Weather Processor <[email-masked]>
Date: Wed, 27 Jan 1999 14:43:05 -0600

005
WTXS34 PGTW 272100
1. TROPICAL CYCLONE 15S (DAMIEN) WARNING NR 013
   03 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
    ---
   WARNING POSITION:
   271800Z8 --- NEAR 14.9S4 91.9E9
     MOVEMENT PAST SIX HOURS - 245 DEGREES AT 07 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
   RADIUS OF 050 KT WINDS - 025 NM SOUTHWEST SEMICIRCLE
                            020 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 150 NM SOUTHWEST SEMICIRCLE
                            100 NM ELSEWHERE
   REPEAT POSIT: 14.9S4 91.9E9
    ---
   FORECASTS:
   12 HRS, VALID AT:
   280600Z6 --- 15.5S1 90.8E7
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   RADIUS OF 050 KT WINDS - 025 NM SOUTHWEST SEMICIRCLE
                            020 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 150 NM SOUTHWEST SEMICIRCLE
                            100 NM ELSEWHERE
   VECTOR TO 24 HR POSIT: 250 DEG/ 07 KTS
    ---
   24 HRS, VALID AT:
   281800Z9 --- 15.9S5 89.5E2
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   RADIUS OF 050 KT WINDS - 025 NM SOUTHWEST SEMICIRCLE
                            020 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 150 NM SOUTH SEMICIRCLE
                            100 NM ELSEWHERE
   VECTOR TO 36 HR POSIT: 260 DEG/ 07 KTS
    ---
   36 HRS, VALID AT:
   290600Z7 --- 16.1S8 88.1E7
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   RADIUS OF 050 KT WINDS - 025 NM SOUTHWEST SEMICIRCLE
                            020 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 150 NM SOUTH SEMICIRCLE
                            100 NM ELSEWHERE
   VECTOR TO 48 HR POSIT: 270 DEG/ 08 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   291800Z0 --- 16.1S8 86.4E8
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   RADIUS OF 035 KT WINDS - 140 NM SOUTH SEMICIRCLE
                            100 NM ELSEWHERE
   VECTOR TO 72 HR POSIT: 280 DEG/ 07 KTS
    ---
   72 HRS, VALID AT:
   301800Z2 --- 15.6S2 83.5E6
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   RADIUS OF 035 KT WINDS - 140 NM SOUTH SEMICIRCLE
                            100 NM ELSEWHERE
    ---
REMARKS:
272100Z2 POSITION NEAR 15.1S7   91.6E6.
TROPICAL CYCLONE 15S (DAMIEN) HAS TRACKED TOWARDS THE WEST-SOUTHWEST
 AT 7 KNOTS DURING THE PAST 6 HOURS. THE WARNING POSITION IS BASED
ON 271730Z0 ANIMATED INFRARED SATELLITE IMAGERY. THE WARNING
INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF T3.5
 (55 KNOTS). TC 15S (DAMIEN) HAS TRACKED SLIGHTLY SOUTH OF THE
PREVIOUS FORECAST TRACK DUE TO VERTICAL SHEARING ON THE SYSTEM.
UPPER LEVEL STEERING IS TENDING TO DIRECT THE CONVECTION TOWARDS
THE SOUTHWEST, WHILE A WEAKNESS IN THE SUBTROPICAL RIDGE EXISTS TO
THE SOUTH OF THE SYSTEM AT THE MID LEVELS. THE WEAKNESS MAY PROVIDE
WEAKER BUT MORE WESTWARD STEERING FLOW FOR THE LOW LEVEL CIRCULATION.
TC 15S (DAMIEN) IS FORECAST TO CONTINUE ON A MORE SOUTHWESTWARD
TRACK OVER THE NEXT 12 HOURS WITHIN THE STEERING FLOW OF THE UPPER
LEVELS DRIVING THE CONVECTION. AFTER THE 12 TO 24 HOUR FORECAST
PERIOD, TC 15S (DAMIEN) IS EXPECTED TO TRACK BACK TOWARDS THE WEST.
THE SHEARING ON THE SYSTEM WILL CAUSE THE MID AND LOWER LEVEL
STEERING FLOW TO DOMINATE THE MOVEMENT OF THE SYSTEM THROUGHOUT
THE REMAINDER OF THE 72 HOUR PERIOD. OUTFLOW ALOFT REMAINS GOOD
OVER THE WESTERN HALF OF THE SYSTEM, BUT MODERATE SHEAR SHOULD
INHIBIT ANY SIGNIFICANT DEVELOPMENT. TC 15S (DAMIEN) IS THEREFORE
FORECAST TO REMAIN AT A RELATIVELY CONSTANT INTENSITY WITH SOME
SLOW WEAKENING OF THE LOW LEVEL WIND FIELD TOWARDS THE END OF THE
72 HOUR PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 271800Z IS 20
FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION.
NEXT WARNINGS AT 280300Z3 (DTG 280157Z3), 280900Z9 (DTG 280757Z9),
281500Z6 (DTG 281357Z6) AND 282100Z3 (DTG 281957Z2). REFER TO
TROPICAL CYCLONE  14P (PETE) WARNINGS (WTXS33 PGTW)FOR SIX-HOURLY
UPDATES. REFER TO TROPICAL CYCLONE  16P (NONAME)WARNINGS (WTXS31
PGTW)FOR SIX-HOURLY UPDATES.
//
BT
#7592

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