WTIO30 FMEE 121228



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 12/5/20142015

1.A INTENSE TROPICAL CYCLONE  5  (BANSI)



2.A POSITION 2015/01/12 AT 1200 UTC:

WITHIN 20 NM RADIUS OF POINT 17.5 S / 56.6 E

(SEVENTEEN    DECIMAL FIVE   DEGREES SOUTH AND FIFTY SIX    DECIMAL

SIX   DEGREES EAST)

MOVEMENT : EAST-SOUTH-EAST 7 KT



3.A DVORAK ANALYSIS: 6.0/6.0/D 2.5/24 H



4.A CENTRAL PRESSURE: 945 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 100 KT

RADIUS OF MAXIMUM WINDS (RMW) :19 KM



6.A EXTENSION OF WIND BY QUADRANTS (KM):

28 KT NE: 300 SE: 370 SW: 260 NW: 240

34 KT NE: 170 SE: 120 SW: 90 NW: 170

48 KT NE: 100 SE: 80 SW: 60 NW: 100

64 KT NE: 60 SE: 60 SW: 60 NW: 60



7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1008 HPA / 700 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2015/01/13 00 UTC: 17.6 S / 57.3 E, MAX WIND=110 KT, INTENSE

TROPICAL CYCLONE

24H: 2015/01/13 12 UTC: 17.8 S / 57.9 E, MAX WIND=110 KT, INTENSE

TROPICAL CYCLONE

36H: 2015/01/14 00 UTC: 18.0 S / 58.4 E, MAX WIND=105 KT, INTENSE

TROPICAL CYCLONE

48H: 2015/01/14 12 UTC: 18.4 S / 58.9 E, MAX WIND=100 KT, INTENSE

TROPICAL CYCLONE

60H: 2015/01/15 00 UTC: 18.9 S / 59.5 E, MAX WIND=095 KT, INTENSE

TROPICAL CYCLONE

72H: 2015/01/15 12 UTC: 20.0 S / 60.6 E, MAX WIND=090 KT, INTENSE

TROPICAL CYCLONE



2.B LONGER-RANGE OUTLOOK :

96H: 2015/01/16 12 UTC: 23.7 S / 63.8 E, MAX WIND=080 KT, TROPICAL

CYCLONE

120H: 2015/01/17 12 UTC: 27.9 S / 69.1 E, MAX WIND=070 KT, TROPICAL

CYCLONE



2.C ADDITIONAL INFORMATIONS:

T=6.0-  AND CI=6.0



THE SYSTEM SHOWED A GOOD SATELLITE FEATURES (CONVENTIONAL AND

MICRO-WAVE) AT MID-DAY. SINCE 1100Z, INNER CORE HAS SHOWN SOME RATHER

SIGNIFICANT FLUCTUATIONS OVER THE SOUTHERN PORTION OF THE EYEWALL AS

SEEN OVER RADAR DATA OF REUNION ISLAND (COLORADO).



BANSI HAS TRACKED GENERALLY EASTWARD UNDER THE STEERING INFLUENCE OF

MID-LEVEL RIDGE WHICH IS BUILDING NORTH OF THE SYSTEM.

BANSI SHOULD KEEP THIS TRACK DURING THE NEXT 36H AND PROBABLY SLOW

DOWN TOMORROW WITHIN A WEAK STEERING ENVIRONMENT.



ON WEDNESDAY, THE MID-LEVEL RIDGE SHIFTS BACK IN THE EAST OF THE

SYSTEM AND A COL BUILDS IN ITS SOUTH, A SOUTH-EASTWARDS MOTION IS

THEN EXPECTED.

BANSI IS THEN EXPECTED TO KEEPS ON TRACKING AND ACCELERATING

SOUTH-EASTWARDS UNTIL SATURDAY.



ON THIS FORECAST TRACK, ENVIRONMENTAL CONDITIONS ARE VERY FAVOURABLE

ON MONDAY, TUESDAY AND WEDNESDAY UNDER THE UPPER LEVEL RIDGE AXIS AS

AT LEAST 2 UPPER LEVEL CHANNELS EQUATOR-WARD AND POLEWARD TAKE PLACE

WITHIN THE PERIOD. A THIRD ONE TOWARDS THE EAST IS EXPECTED TO

TEMPORARILY EXIST ON TUESDAY.

ON AND AFTER THURSDAY, BANSI SHIFTS SOUTH OF THE UPPER LEVEL RIDGE

AXIS AND KEEPS ONLY ITS POLEWARD OUTFLOW CHANNEL.

A WESTERLY VERTICAL WINDSHEAR STRENGTHENS ON FRIDAY OVER LIMITED HEAT

OCEANIC CONTENTS.



THERE IS AN IMPORTANT LIKELIHOOD THAT A VERY DANGEROUS INTENSE

TROPICAL CYCLONE REPRESENTS A POTENTIAL THREAT FOR THE MASCAREIGNES

WITHIN SEVERAL DAYS (FROM MONDAY TO THURSDAY).



THE INHABITANTS OF THE MASCAREIGNES ISLANDS SHOULD THEREFORE CLOSELY

MONITOR THE PROGRESS OF THIS DANGEROUS SYSTEM WITHIN THE NEXT DAYS.=