Subject: Indian-S: 01 Active Tropical Cyclone In Southern Hemisphere

From: SIU Weather Processor <[email-masked]>
Date: Sat, 6 Feb 1999 08:40:48 -0600

482
WTXS31 PGTW 061500
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).
//
BT
#7663

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