WTIO30 FMEE 311247



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 18/5/20172018

1.A TROPICAL CYCLONE  5  (CEBILE)



2.A POSITION 2018/01/31 AT 1200 UTC:

WITHIN 15 NM RADIUS OF POINT 15.6 S / 77.3 E

(FIFTEEN    DECIMAL SIX   DEGREES SOUTH AND SEVENTY SEVEN    DECIMAL

THREE   DEGREES EAST)

MOVEMENT : WEST 4 KT



3.A DVORAK ANALYSIS: 5.0/5.0/W 0.5/24 H



4.A CENTRAL PRESSURE: 962 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 80 KT

RADIUS OF MAXIMUM WINDS (RMW) :46 KM



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

28 KT NE: 260 SE: 350 SW: 390 NW: 220

34 KT NE: 150 SE: 240 SW: 240 NW: 150

48 KT NE: 110 SE: 150 SW: 150 NW: 110

64 KT NE: 90 SE: 100 SW: 100 NW: 90



7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1008 HPA / 1200 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2018/02/01 00 UTC: 15.9 S / 76.3 E, MAX WIND=090 KT, INTENSE

TROPICAL CYCLONE

24H: 2018/02/01 12 UTC: 16.2 S / 75.8 E, MAX WIND=095 KT, INTENSE

TROPICAL CYCLONE

36H: 2018/02/02 00 UTC: 16.8 S / 75.4 E, MAX WIND=090 KT, INTENSE

TROPICAL CYCLONE

48H: 2018/02/02 12 UTC: 17.6 S / 75.4 E, MAX WIND=080 KT, TROPICAL

CYCLONE

60H: 2018/02/03 00 UTC: 18.1 S / 75.9 E, MAX WIND=065 KT, TROPICAL

CYCLONE

72H: 2018/02/03 12 UTC: 18.8 S / 77.2 E, MAX WIND=060 KT, SEVERE

TROPICAL STORM



2.B LONGER-RANGE OUTLOOK :

96H: 2018/02/04 12 UTC: 21.5 S / 80.0 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM

120H: 2018/02/05 12 UTC: 24.6 S / 80.9 E, MAX WIND=050 KT,

POST-TROPICAL DEPRESSION



2.C ADDITIONAL INFORMATION:

T=CI=5.0



OVER THE LAST 6 HOURS, CEBILE WIDE EYE PATTERN DID NOT EVOLVE. THE

EYE CONTRACTION OBSERVED IN THE EARLY MORNING, STOPPED APPARENTLY.

THE RSMC DVORAK ESTIMATES, IS THUS STILL LIMITED BY THE EYE SIZE.



CEBILE KEEPS ON TRACKING MAINLY WESTWARDS. THE SYSTEM IS CAUGHT

BETWEEN A SUBTROPICAL RIDGE IN THE SOUTH-WEST AND THE NEAR-EQUATORIAL

RIDGE IN THE NORTH-EAST. THESE TWO SYNOPTIC STRUCTURES ARE DRIVING

OPPOSITE STEERING FLOWS. HOWEVER, FROM TOMORROW, THE FIRST ONE IS

EXPECTED TO DECAY, MAKING THE MAIN STEERING FLOW PROGRESSIVELY DRIVEN

BY THE SECOND ONE. THIS CHANGE WILL LEAD TO A SHARP SOUTH-EASTWARD

TURN FOLLOWED BY A GRADUAL ACCELERATION. THE GUIDANCE DISPERSION

REMAINS IMPORTANT BECAUSE OF THE UNCERTAINTY OVER THE EXACT TRACK OF

THE SYSTEM OVER THE NEXT HOURS. DIFFERENT SCENARIOS SEEMS TO START

CONVERGING TOWARDS AN INTERMEDIATE SOLUTION. THE CURRENT TRACK

FORECAST IS MOSTLY BASED ON A CONSENSUS OF RECENT IFS AND GFS

GUIDANCE.



UNTIL TOMORROW, CEBILE SHOULD EVOLVE WITHIN QUASI-PERFECT CONDITIONS

CONCERNING WIND SHEAR, UPPER DIVERGENCE AND OCEANIC HEAT CONTENT. AN

INTENSIFICATION IS STILL POSSIBLE AT SHORT RANGE. FROM THURSDAY

EVENING, EQUATORWARD UPPER LEVEL DIVERGENCE IS EXPECTED TO WEAKEN BUT

THIS DECREASE SHOULD BE OFFSET BY AN INCREASING POLARWARD CHANNEL

OUTFLOW. MOREOVER, IF THE MOTION IS SLOWER THAN EXPECTED WHEN IT

SHOULD CURVE SOUTHEASTWARD, THE SELF-INDUCED SST COOLING COULD

SIGNIFICANTLY DECREASE CEBILE'S INTENSITY. FROM FRIDAY EVENING, A

ROSSBY WAVE BREAKING LOCATED WEST OF THE SYSTEM WILL INCREASE QUICKLY

THE NORTHWESTWARD VERTICAL WINDSHEAR AND CEBILE'S INTENSITY IS

FORECAST TO QUICKLY DECREASE AS IT WILL MOVE OVER COOLER SURFACE SEA

TEMPERATURE. AT LAST THE SYSTEM MAY THEN BEGIN ITS

EXTRA-TROPICALISATION PHASE.=