Subject: Indian-S: 1. Tropical Cyclone 28s (fiona) Warning Nr 001

From: SIU Weather Processor <[email-masked]>
Date: Mon, 16 Mar 1998 20:56:20 -0600

493
WTXS31 PGTW 170300
IMMEDIATE DELIVERY REQ TO AMEMBASSY PORT LOUIS
1. TROPICAL CYCLONE 28S (FIONA) WARNING NR 001
   02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
    ---
   WARNING POSITION:
   170000Z8 --- 17.4S2 61.5E2

PAGE 02 RUHPSGG3623 UNCLAS
     MOVEMENT PAST SIX HOURS - 200 DEGREES AT 05 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 - 040 NM EAST SEMICIRCLE
                            035 NM ELSEWHERE
   REPEAT POSIT: 17.4S2 61.5E2
    ---
   FORECASTS:
   12 HRS, VALID AT:
   171200Z1 --- 18.1S0 61.3E0
   MAX SUSTAINED WINDS - 050 KT, GUSTS 060 KT
   RADIUS OF 035 KT WINDS - 050 NM EAST SEMICIRCLE
                            040 NM ELSEWHERE
   VECTOR TO 24 HR POSIT: 210 DEG/ 04 KTS
    ---
   24 HRS, VALID AT:
   180000Z9 --- 18.7S6 60.9E5
   MAX SUSTAINED WINDS - 060 KT, GUSTS 070 KT

PAGE 03 RUHPSGG3623 UNCLAS
   RADIUS OF 050 KT WINDS - 020 NM
   RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE
                            050 NM ELSEWHERE
   VECTOR TO 36 HR POSIT: 240 DEG/ 04 KTS
    ---
   36 HRS, VALID AT:
   181200Z2 --- 19.1S1 60.2E8
   MAX SUSTAINED WINDS - 070 KT, GUSTS 080 KT
   RADIUS OF 050 KT WINDS - 035 NM
   RADIUS OF 035 KT WINDS - 080 NM SOUTHEAST SEMICIRCLE
                            065 NM ELSEWHERE
   VECTOR TO 48 HR POSIT: 250 DEG/ 04 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   190000Z0 --- 19.4S4 59.4E8
   MAX SUSTAINED WINDS - 080 KT, GUSTS 095 KT
   RADIUS OF 050 KT WINDS - 045 NM
   RADIUS OF 035 KT WINDS - 100 NM SOUTH SEMICIRCLE
                            085 NM ELSEWHERE

PAGE 04 RUHPSGG3623 UNCLAS
    ---
REMARKS:
170300Z1 POSITION 17.6S4 61.4E1.
THE TROPICAL DISTURBANCE LOCATED EAST OF THE MASCARENE ISLANDS
WHICH WAS THE SUBJECT OF A TROPICAL CYCLONE FORMATION ALERT HAS
CONTINUED TO DEVELOP INTO TROPICAL CYCLONE 28S (FIONA). THIS
SYSTEM IS LOCATED IN A VERY FAVORABLE UPPER-LEVEL SYNOPTIC
PATTERN SIMILAR TO TC 27S (ELSIE) WAS 3 TO 4 DAYS AGO. AS A
RESULT, WE ARE EXPECTING A FASTER THAN NORMAL RATE OF
INTENSIFICATION THROUGHOUT THE FORECAST PERIOD. SATELLITE
IMAGERY INDICATES A SMALL CENTRAL DENSE OVERCAST FEATURE HAS
DEVELOPED OVER THE SYSTEM CENTER WHILE A POLEWARD OUTFLOW
CHANNEL HAS LINKED UP WITH THE MID-LATITUDE WESTERLIES. GOOD
CROSS-EQUATORIAL INFLOW HAS ALSO DEVELOPED IN THE NORTH AND
EAST QUADRANTS AS INDICATED BY SEVERAL CONVECTIVE BANDS NOTED
SPIRALING INTO THE SYSTEM CENTER. OUR FORECAST TRACK HAS
FOLLOWED A BLEND OF OUR CLIMATOLOGICAL AIDS AND OUR DYNAMIC
AID, FBAM, BY TAKING TC 28S (FIONA) SLOWLY SOUTHWARD INTO THE
MEAN SUBTROPICAL RIDGE AXIS AND THEN TRACKING THE SYSTEM SLOWLY
WEST-SOUTHWESTWARD AS INDICATED BY THE FBAM MODEL AFTER 24

PAGE 05 RUHPSGG3623 UNCLAS
HOURS. THERE IS STILL SOME UNCERTAINTY CONCERNING THE EXACT
LOCATION OF THE SYSTEM CENTER WHICH WILL ULTIMATELY AFFECT
THE FUTURE TRACK. HOWEVER, THE CURRENT SYNOPTIC PATTERN AND
FORECAST MODELS INDICATE TC 28S (FIONA) IS AND WILL REMAIN
EMBEDDED IN A WEAK STEERING ENVIRONMENT WHICH SUPPORTS OUR
GENERAL FORECAST TRACK OF SLOW SOUTHWEST MOTION. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 170000Z8 IS 10 FEET. NEXT WARNINGS
AT 171500Z4 (DTG 171351Z8) AND 180300Z2 (DTG 180151Z6).
THIS WARNING SUPERSEDES AND CANCELS NAVPACMETOCCEN WEST GU
161951Z MAR 98 TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW
162000 ) REFER TO TROPICAL CYCLONE 27S (ELSIE) WARNINGS (WTXS32
PGTW) FOR TWELVE-HOURLY UPDATES.//
BT
#3623

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