Subject: Indian-S: 1. Tropical Cyclone 28s (elaine) Warning Nr 004

From: SIU Weather Processor <[email-masked]>
Date: Wed, 17 Mar 1999 14:02:36 -0600

999
WTXS32 PGTW 172100
SUBJ:  TROPICAL CYCLONE WARNING
1. TROPICAL CYCLONE 28S (ELAINE) WARNING NR 004
   03 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
    ---
   WARNING POSITION:
   171800Z7 --- NEAR 17.8S6 111.1E4
     MOVEMENT PAST SIX HOURS - 210 DEGREES AT 08 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 - 090 NM SOUTHEAST SEMICIRCLE
                            080 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 180 NM SOUTHEAST SEMICIRCLE
                            170 NM ELSEWHERE
   REPEAT POSIT: NEAR 17.8S6 111.1E4
    ---
   FORECASTS:
   12 HRS, VALID AT:
   180600Z5 --- 18.9S8 110.2E4
   MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
   RADIUS OF 050 KT WINDS - 090 NM SOUTHEAST SEMICIRCLE
                            080 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 200 NM SOUTHEAST SEMICIRCLE
                            170 NM ELSEWHERE
   VECTOR TO 24 HR POSIT: 210 DEG/ 08 KTS
    ---
   24 HRS, VALID AT:
   181800Z8 --- 20.3S5 109.4E4
   MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
   RADIUS OF 050 KT WINDS - 080 NM SOUTHEAST SEMICIRCLE
                            090 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 210 NM SOUTHEAST SEMICIRCLE
                            180 NM ELSEWHERE
   VECTOR TO 36 HR POSIT: 215 DEG/ 07 KTS
    ---
   36 HRS, VALID AT:
   190600Z6 --- 21.4S7 108.6E5
   MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
   RADIUS OF 050 KT WINDS - 090 NM SOUTHEAST SEMICIRCLE
                            080 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 215 NM SOUTHEAST SEMICIRCLE
                            175 NM ELSEWHERE
   VECTOR TO 48 HR POSIT: 210 DEG/ 08 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   191800Z9 --- 22.8S2 107.7E5
   MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
   RADIUS OF 050 KT WINDS - 080 NM SOUTHEAST SEMICIRCLE
                            075 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 215 NM SOUTHEAST SEMICIRCLE
                            175 NM ELSEWHERE
    ---
REMARKS:
172100Z1 POSITION NEAR 18.1S0  110.9E1.
TROPICAL CYCLONE (TC) 28S (ELAINE) HAS TRACKED SOUTH-SOUTHWESTWARD
OFF THE NORTHWEST COAST OF AUSTRALIA AT 08 KNOTS OVER THE PAST 12
HOURS. THE WARNING POSITION IS BASED UPON 171730Z9 ANIMATED INFRARED
SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED UPON A SATELLITE
CURRENT INTENSITY ESTIMATE OF 90 KNOTS. ANIMATED INFRARED SATELLITE
IMAGERY INDICATES SOME OF THE DEEP CONVECTION ASSOCIATED WITH TC 28S
IS BEING SHEARED TO THE SOUTHEAST. TROPICAL CYCLONE 28S IS TRACKING
SOUTH-SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL
RIDGE LOCATED TO ITS SOUTHEAST. TC 28S IS FORECAST TO TRACK
SOUTH-SOUTHWESTWARD THROUGHOUT THE FORECAST PERIOD. AS TC 28S
CONTINUES TO TRACK SOUTHWARD, UW-CIMSS SHEAR CHARTS INDICATE IT WILL
BE ENTERING AN AREA OF INCREASED VERTICAL WIND SHEAR. HENCE, TC 28S
IS NO LONGER FORECAST TO INTENSIFY. THE INCREASED VERTICAL WIND
SHEAR CAN ALSO LEAD TO A MEDIUM CONFIDENCE ALTERNATE FORECAST TRACK
 SCENARIO. IF THE CONVECTION IS TOTALLY SHEARED FROM THE SYSTEM, THE
 LOW LEVEL CIRCULATION SHOULD TRACK MORE WESTWARD AFTER THE 24 HOUR
 FORECAST POSITION UNDER THE INFLUENCE OF A LOW LEVEL RIDGE. THE
WIND RADII ARE BASED ON AN EARLIER SCATTEROMETRY PASS. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 171800Z7 IS 22 FEET. NEXT WARNINGS AT
180900Z8 (DTG180753Z4) AND 182100Z2 (DTG 181953Z7). REFER TO
TROPICAL CYCLONE 27P (HALI) WARNINGS (WTPS31 PGTW) FOR
TWELVE-HOURLY UPDATES. REFER TO TROPICAL CYCLONE 29S WARNINGS
(WTXS33 PGTW) FOR SIX-HOURLY UPDATES.//
BT
#0004

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