WTIO30 FMEE 010617



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 21/5/20172018

1.A INTENSE TROPICAL CYCLONE  5  (CEBILE)



2.A POSITION 2018/02/01 AT 0600 UTC:

WITHIN 21 NM RADIUS OF POINT 15.6 S / 76.2 E

(FIFTEEN    DECIMAL SIX   DEGREES SOUTH AND SEVENTY SIX    DECIMAL

TWO   DEGREES EAST)

MOVEMENT : WEST 2 KT



3.A DVORAK ANALYSIS: 6.0/6.0/D 0.5/6 H



4.A CENTRAL PRESSURE: 952 HPA

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

RADIUS OF MAXIMUM WINDS (RMW) :28 KM



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

28 KT NE: 260 SE: 460 SW: 460 NW: 260

34 KT NE: 190 SE: 220 SW: 280 NW: 190

48 KT NE: 70 SE: 70 SW: 70 NW: 110

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



7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1005 HPA / 600 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2018/02/01 18 UTC: 16.2 S / 75.6 E, MAX WIND=105 KT, INTENSE

TROPICAL CYCLONE

24H: 2018/02/02 06 UTC: 16.8 S / 75.4 E, MAX WIND=110 KT, INTENSE

TROPICAL CYCLONE

36H: 2018/02/02 18 UTC: 17.5 S / 75.6 E, MAX WIND=100 KT, INTENSE

TROPICAL CYCLONE

48H: 2018/02/03 06 UTC: 18.0 S / 76.5 E, MAX WIND=080 KT, TROPICAL

CYCLONE

60H: 2018/02/03 18 UTC: 18.7 S / 78.2 E, MAX WIND=065 KT, TROPICAL

CYCLONE

72H: 2018/02/04 06 UTC: 19.8 S / 79.5 E, MAX WIND=060 KT, SEVERE

TROPICAL STORM



2.B LONGER-RANGE OUTLOOK :

96H: 2018/02/05 06 UTC: 22.9 S / 80.9 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM

120H: 2018/02/06 06 UTC: 26.6 S / 81.2 E, MAX WIND=050 KT,

EXTRATROPICAL DEPRESSION



2.C ADDITIONAL INFORMATION:

T=CI=6.0-



AFTER A PERIOD WHEN CONVECTION HAS REMAINED, THE LATEST INFRARED DATA

SHOW A WEAKNESS IN THE CONVECTIVE RING SURROUNDING CEBILE'S EYE.

DESPITE THIS WEAKNESS IN THE SOUTHERN SEMI-CIRCLE, THE CONTRACTION OF

THE EYE ALLOWS A DVORAK ANALYSIS SLIGHTLY UP.



THE SLOW MOTION OF CEBILE REMAINS ON THE LAST SIX HOURS. 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.  TODAY, THE NEAR

EQUATORIAL RIDGE SHOULD THUS TAKE OVER CEBILE'S STEERING FLOW. THE

GUIDANCE DISPERSION BECAME RELATIVELY LOW IN THE LAST MODELS RUNS

ABOUT THE TURN THROUGH THE SOUTHEAST THAT CEBILE WILL TAKE, FOLLOWING

A GRADUAL ACCELERATION FROM TOMORROW.



CEBILE IS CURRENTLY WITHIN QUASI-PERFECT CONDITIONS CONCERNING WIND

SHEAR, UPPER DIVERGENCE AND OCEANIC HEAT CONTENT. A SLIGHT INTENSITY

GAIN IS STILL POSSIBLE AT SHORT RANGE. HOWEVER, THE DRY AIR THAT

SEEMS TO AFFECT CURRENTLY CONVECTION COULD LIMIT THIS SLIGHT

INTENSITY REGAIN. FROM SATURDAY, A ROSSBY WAVE BREAKING LOCATED WEST

OF THE SYSTEM WILL QUICKLY STRENGTHEN THE WESTERLY THEN

NORTHWESTWERLY WINDSHEAR. CEBILE'S INTENSITY IS FORECAST TO QUICKLY

DROP, AS IT WILL ALSO TRACK OVER COOLER SURFACE SEA TEMPERATURES.

LASTLY, THE SYSTEM MAY THEN BEGIN ITS EXTRA-TROPICALISATION PHASE AS

THE UPPER TROUGH.=