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

From: SIU Weather Processor <[email-masked]>
Date: Wed, 3 Mar 1999 02:15:58 -0600

053
WTXS32 PGTW 030900
1. TROPICAL CYCLONE 25S WARNING NR 004A RELOCATED
   01 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
    ---
   WARNING POSITION:
   030600Z9 --- NEAR 10.5S6 90.6E5
     MOVEMENT PAST SIX HOURS - 180 DEGREES AT 04 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 - 060 NM SOUTHWEST SEMICIRCLE
                            050 NM ELSEWHERE
   REPEAT POSIT: 10.5S6 90.6E5
    ---
   FORECASTS:
   12 HRS, VALID AT:
   031800Z2 --- 11.2S4 90.3E2
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   RADIUS OF 035 KT WINDS - 070 NM SOUTH SEMICIRCLE
                            060 NM ELSEWHERE
   VECTOR TO 24 HR POSIT: 240 DEG/ 05 KTS
    ---
   24 HRS, VALID AT:
   040600Z0 --- 11.7S9 89.4E1
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   RADIUS OF 035 KT WINDS - 080 NM SOUTH SEMICIRCLE
                            070 NM ELSEWHERE
   VECTOR TO 36 HR POSIT: 250 DEG/ 06 KTS
    ---
   36 HRS, VALID AT:
   041800Z3 --- 12.1S4 88.2E8
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   RADIUS OF 050 KT WINDS - 015 NM
   RADIUS OF 035 KT WINDS - 090 NM SOUTH SEMICIRCLE
                            080 NM ELSEWHERE
   VECTOR TO 48 HR POSIT: 250 DEG/ 08 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   050600Z1 --- 12.6S9 86.6E0
   MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
   RADIUS OF 050 KT WINDS - 025 NM SOUTH SEMICIRCLE
                            020 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 105 NM SOUTH SEMICIRCLE
                            095 NM ELSEWHERE
    ---
REMARKS:
030900Z2 POSITION NEAR 10.7S8 90.5E4. RELOCATED.
TROPICAL CYCLONE 25S HAS BEEN RELOCATED DUE TO THE AVAILABILITY OF
VISIBLE SATELLITE IMAGERY AND HAS TRACKED TOWARDS THE SOUTH AT 4
KNOTS DURING THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON
030530Z1 VISIBLE SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED
ON SATELLITE CURRENT INTENSITY ESTIMATES OF T3.0 (45 KNOTS) AND
T2.0 (30 KNOTS). THE LOW LEVEL CIRCULATION ASSOCIATED WITH TC 25S
REMAINS EXPOSED TO THE EAST OF THE PRIMARY CONVECTION. THE SYSTEM
REMAINS WITHIN WEAK STEERING FLOW BETWEEN MODERATE EQUATORIAL
WESTERLIES AND A LARGE SUBTROPICAL RIDGE TO THE SOUTH. OVER THE
PAST 24 HOURS, TC 25S HAS REMAINED BETWEEN THESE TWO STEERING
INFLUENCES, CAUSING THE SYSTEM TO REMAIN QUASI-STATIONARY WITH AN
ERRATIC TRACK. TC 25S IS FORECAST TO BE PRIMARILY STEERED BE THE
SUBTROPICAL RIDGE TO THE SOUTH. TC 25S IS FORECAST TO SLOWLY MOVE
SOUTH THEN SOUTHWEST DURING THE NEXT 12 HOURS. AFTERWARDS, TC 25S
IS FORECAST TO ACCELERATE AND TRACK TOWARDS THE WEST-SOUTHWEST
DURING THE REMAINDER OF THE 48 HOUR FORECAST PERIOD. THE SYSTEM
REMAINS UNDER MODERATE WESTWARD VERTICAL SHEAR. THE SHEAR WEAKENS,
HOWEVER, WEST OF THE SYSTEM. A HIGH PRESSURE RIDGE ABOVE TC 25S HAS
ALLOWED OUTFLOW TO REMAIN FAIR, ESPECIALLY TOWARDS THE WEST. TC 25S
IS FORECAST TO SLOWLY INTENSIFY DURING THE NEXT 36 HOUR. THE SYSTEM
IS FORECAST TO INTENSIFY QUICKER AFTER THAT PERIOD. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 030600Z IS 13 FEET. NEXT WARNINGS AT
032100Z6 (DTG 031953Z1) AND 040900Z3 (DTG 040753Z9).
//
BT
#0001

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