Subject: Indian-S: 02 Active Tropical Cyclones In Southern Hemisphere

From: SIU Weather Processor <[email-masked]>
Date: Sat, 5 Dec 1998 13:40:57 -0600

028
WTXS31 PGTW 052100
1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 013
   02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
    ---
   WARNING POSITION:
   051800Z4 --- NEAR 20.3S5 115.0E7
     MOVEMENT PAST SIX HOURS - 180 DEGREES AT 02 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 - 050 NM SOUTHEAST SEMICIRCLE
                            040 NM ELSEWHERE
   REPEAT POSIT: 20.3S5 115.0E7
    ---
   FORECASTS:
   12 HRS, VALID AT:
   060600Z2 --- 20.8S0 114.8E4
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE
                            030 NM ELSEWHERE
   VECTOR TO 24 HR POSIT: 200 DEG/ 03 KTS
    ---
   24 HRS, VALID AT:
   061800Z5 --- 21.3S6 114.6E2
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 36 HR POSIT: 180 DEG/ 04 KTS
    ---
   36 HRS, VALID AT:
   070600Z3 --- 22.0S4 114.5E1
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 48 HR POSIT: 180 DEG/ 04 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   071800Z6 --- 22.9S3 114.4E0
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 72 HR POSIT: 180 DEG/ 05 KTS
    ---
   72 HRS, VALID AT:
   081800Z7 --- 24.8S4 114.3E9
   MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
052100Z8 POSITION NEAR 20.4S6  115.0E7.
TROPICAL CYCLONE 05S (BILLY) HAS DRIFTED SOUTHWARD AT 02 KNOTS
OVER THE PAST 6 HOURS. THE WARNING POSITION AND CURRENT INTENSITY
(45KTS) ARE BASED ON 051730Z6 INFRARED SATELLITE IMAGE ANALYSIS
TECHNIQUES AND A MICROWAVE IMAGER PASS (051253Z6).   ANIMATED
SATELLITE IMAGERY INDICATES THE SYSTEM HAS BECOME QUASI-STATIONARY
OVER THE PAST 6 HOURS. THE MICROWAVE PASS INDICATES THE LOW-LEVEL
CIRCULATION CENTER HAS BECOME EXPOSED. THIS EXPOSURE WOULD INDICATE
AN INCREASE IN VERTICAL WINDSHEAR.  SYNOPTIC WIND REPORTS FROM
BARROW=S ISLAND AUSTRALIA (WMO 94304) OVER THE PAST SEVERAL HOURS
INDICATE THE SYSTEM IS IS QUASI-STATIONARY. UW CIMSS WINDSHEAR
PRODUCTS AND ANIMATED WATER VAPOR IMAGERY INDICATE TC 05S (BILLY) IS
MOVING INTO AN AREA OF MODERATE VERTICAL WINDSHEAR. ANIMATION ALSO
REVEALS SEVERAL OUTFLOW BOUNDARIES FROM THUNDERSTORMS INTERSECTING
IN THE VICINITY OF THE SYSTEM. TC 05S (BILLY) IS FORECAST TO
CONTINUE TO DRIFT SOUTHWARD WITH THE LOW-MID LEVEL STEERING FLOW OF
THE SUBTROPICAL RIDGE TO THE SOUTH. TROPICAL CYCLONE 05S (BILLY)
SHOULD ALSO COUNTINUE TO WEAKEN AS IT APPROACHES THE NORTHWEST COAST
OF AUSTRALIA DUE TO THE INCREASED WINDSHEAR ENVIRONMENT. AFTER
MAKING LANDFALL, TC 05S (BILLY) SHOULD DISSIPATE EVEN MORE RAPIDLY
DUE TO LAND INTERACTION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051800Z4
IS 14 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT
INFORMATION. NEXT WARNINGS AT 060300Z9 (DTG 060151Z3), 060900Z5 (DTG
060751Z9), 061500Z2 (DTG 061351Z6) AND 062100Z9 (DTG 061951Z2).
REFER TO TROPICAL CYCLONE  06S (NONAME) WARNINGS (WTXS32 PGTW)
FOR SIX-HOURLY UPDATES.//

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