Subject: Indian-S: 1. Tropical Cyclone 25s (davina) Warning Nr 022

From: SIU Weather Processor <[email-masked]>
Date: Thu, 11 Mar 1999 02:22:08 -0600

999
WTXS32 PGTW 110900
IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT LOUIS
1. TROPICAL CYCLONE 25S (DAVINA) WARNING NR 022
   01 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
    ---
   WARNING POSITION:
   110600Z8 --- NEAR 23.0S5 53.2E0
     MOVEMENT PAST SIX HOURS - 250 DEGREES AT 03 KTS
     POSITION ACCURATE TO WITHIN 060 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
   RADIUS OF 050 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE
                            055 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 180 NM SOUTHEAST SEMICIRCLE
                            160 NM ELSEWHERE
   REPEAT POSIT: 23.0S5 53.2E0
    ---
   FORECASTS:
   12 HRS, VALID AT:
   111800Z1 --- 23.5S0 52.5E2
   MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
   RADIUS OF 050 KT WINDS - 060 NM SOUTHEAST SEMICIRCLE
                            050 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 170 NM SOUTHEAST SEMICIRCLE
                            150 NM ELSEWHERE
   VECTOR TO 24 HR POSIT: 225 DEG/ 04 KTS
    ---
   24 HRS, VALID AT:
   120600Z9 --- 24.1S7 51.8E4
   MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
   RADIUS OF 050 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE
                            040 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 150 NM SOUTHEAST SEMICIRCLE
                            130 NM ELSEWHERE
   VECTOR TO 36 HR POSIT: 230 DEG/ 06 KTS
    ---
   36 HRS, VALID AT:
   121800Z2 --- 24.9S5 50.7E2
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   RADIUS OF 050 KT WINDS - 035 NM SOUTHEAST SEMICIRCLE
                            030 NM ELSEWHERE
   RADIUS OF 035 KT WINDS - 120 NM SOUTHEAST SEMICIRCLE
                            110 NM ELSEWHERE
   VECTOR TO 48 HR POSIT: 245 DEG/ 09 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   130600Z0 --- 25.7S4 48.9E1
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   RADIUS OF 035 KT WINDS - 090 NM SOUTH SEMICIRCLE
                            075 NM ELSEWHERE
    ---
REMARKS:
110900Z1 POSITION NEAR 23.1S6   53.0E8.
TROPICAL CYCLONE 25S (DAVINA) HAS SLOWED AND TRACKED WEST-
SOUTHWESTWARD AT 3 KNOTS DURING THE PAST 6 HOURS. THE WARNING
POSITION IS BASED ON 110530Z0 INFRARED SATELLITE IMAGERY. THE
WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES
OF T4.5 (77 KNOTS). TC 25S (DAVINA) HAS MOVED INTO A REGION OF WEAK
STEERING FLOW BETWEEN THE SUBTROPICAL RIDGE TO THE SOUTHEAST AND
THE SUBTROPICAL RIDGE SOUTHWEST OF THE SYSTEM. THE RIDGE TO
THE SOUTHWEST HAS NOT BUILT AS FAR EAST AS PREVIOUSLY FORECASTED IN
ORDER TO STEER THE ENTIRE SYSTEM FURTHER WEST. TC 25S (DAVINA) IS
FORECAST TO SLOWLY TRACK SOUTHWESTWARD DURING THE FIRST 24 HOURS.
AS INCREASING SHEAR BEGINS TO INTERACT WITH THE SYSTEM, LOWER LEVEL
STEERING FLOW SHOULD BEGIN TO AGAIN TRACK THE WEAKENING SYSTEM (LOW
LEVEL CIRCULATION CENTER) ON A WEST-SOUTHWESTWARD TRACK. A LARGE
PORTION OF THE CONVECTION ASSOCIATED WITH THE SYSTEM MAY BEGIN TO
SHEAR TOWARDS THE EAST-SOUTHEAST IN RESPONSE TO STRONGER UPPER
LEVEL WESTERLY FLOW CURRENTLY SOUTH OF THE SYSTEM. TC 25S (DAVINA)
IS FORECAST TO SLOWLY WEAKEN DURING THE INITIAL 36 HOURS OF THE
FORECAST PERIOD. THE SYSTEM IS FORECAST TO BEGIN DISSIPATING OVER
WATER BY THE 48 HOUR FORECAST PERIOD. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 110600Z IS 25 FEET. REFER TO WWIO30 PGFW FOR ADDITIONAL
SEA HEIGHT INFORMATION. NEXT WARNINGS AT 112100Z5 (DTG 111953Z0)
AND 120900Z2 (DTG 120753Z8).
//
BT
#0001

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