WTIO30 FMEE 071805



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 18/4/20162017

1.A MODERATE TROPICAL STORM  4  (CARLOS)



2.A POSITION 2017/02/07 AT 1800 UTC:

WITHIN 20 NM RADIUS OF POINT 20.5 S / 54.1 E

(TWENTY    DECIMAL FIVE   DEGREES SOUTH AND FIFTY FOUR    DECIMAL ONE

DEGREES EAST)

MOVEMENT : SOUTH-WEST 9 KT



3.A DVORAK ANALYSIS: 2.5/2.5/S 0.0/12 H



4.A CENTRAL PRESSURE: 998 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 35 KT

RADIUS OF MAXIMUM WINDS (RMW) :37 KM



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

28 KT NE: 110 SE: 370 SW: 370 NW: 110

34 KT NE: 70 SE: 90 SW: 90 NW: 70







7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1008 HPA / 800 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2017/02/08 06 UTC: 22.1 S / 52.5 E, MAX WIND=040 KT, MODERATE

TROPICAL STORM

24H: 2017/02/08 18 UTC: 22.7 S / 51.7 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM

36H: 2017/02/09 06 UTC: 23.8 S / 52.0 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM

48H: 2017/02/09 18 UTC: 24.7 S / 53.0 E, MAX WIND=055 KT, SEVERE

TROPICAL STORM

60H: 2017/02/10 06 UTC: 25.3 S / 54.4 E, MAX WIND=055 KT, SEVERE

TROPICAL STORM

72H: 2017/02/10 18 UTC: 26.6 S / 57.0 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM



2.B LONGER-RANGE OUTLOOK :

96H: 2017/02/11 18 UTC: 27.9 S / 56.9 E, MAX WIND=040 KT,

POST-TROPICAL DEPRESSION

120H: 2017/02/12 18 UTC: 29.0 S / 56.1 E, MAX WIND=030 KT,

POST-TROPICAL DEPRESSION



2.C ADDITIONAL INFORMATION:

T=2.5 CI=2.5+



SINCE A FEW HOURS, DEEP CONVECTION HAS REBUILT IN THE WEST AND SOUTH

PARTS OF THE CIRCULATION, ASSOCIATED WITH A STRONG THUNDERSTORM

ACTIVITY.

THE CENTER IS LOCATED THANKS TO RADAR DATA OF LA REUNION.

THUS, THE UPPER CONSTRAINT HAS CLEARLY WEAKENED AND IS EVALUATED AT

5-10KT IN THE LAST CIMSS ESTIMATES.



CARLOS GOES ON TRACKING SOUTH-WESTWARD AGAIN. FROM TOMORROW, UNDER

THE GROWING INFLUENCE OF A MID-TROPOSPHERIC RIDGE IN THE NORTH-EAST

AND A SURFACE TROUGH IN THE SOUTH COMING FROM THE MID-LATITUDES,

CARLOS' TRACK SHOULD BEND SOUTHWARD THEN SOUTH-EASTWARD. SATURDAY, AT

THE END OF THE TAUS, ENSEMBLE PREDICTION DATA SHOW A STRONG

UNCERTAINTY ON CARLOS' TRACK. FOR NOW, THE DETERMNISTIC MODELS ARE IN

RATHER GOOD AGREEMENT TO FORECAST A NEW SOUTH-WESTWARD TURN STEERED

BY A HIGH PRESSURE CELL CENTERED IN THE SOUTH-EAST.



THE UPPER DIVERGENCE REMAINS STRONG IN THE SOUTH-EASTERN QUADRANT OF

CARLOS. THUS, A INTENSIFICATION WINDOW STILL EXISTS UNTIL TOMORROW

NIGHT WITH A BUILDING POLAR OUTFLOW CHANEL. FROM THURSDAY, CARLOS

SHOULD TRACK AHEAD OF AN UPPER TROUGH COMING FROM THE MID-LATITUDES.

AT FIRST, CARLOS' SOUTH-EASTWARD TRACK SHOULD MITIGATE THE INFLUENCE

OF THE MODERATE WESTERLY SHEAR. BY SATURDAY, THE SHEAR SHOULD BE TOO

STRONG AND CARLOS SHOULD BEGIN TO WEAKEN. FURTHER MORE, THE PROXIMITY

OF THE UPPER TROUGH COULD BEGIN TO TRIGGER AN EXTRATROPICALISATION

PHASE.=