WTIO30 FMEE 211230



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 5/3/20152016

1.A MODERATE TROPICAL STORM  3  (CORENTIN)



2.A POSITION 2016/01/21 AT 1200 UTC:

WITHIN 30 NM RADIUS OF POINT 15.8 S / 74.3 E

(FIFTEEN    DECIMAL EIGHT   DEGREES SOUTH AND SEVENTY FOUR    DECIMAL

THREE   DEGREES EAST)

MOVEMENT : SOUTH-SOUTH-WEST 9 KT



3.A DVORAK ANALYSIS: 2.5/2.5/D 1.0/24 H



4.A CENTRAL PRESSURE: 990 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT

RADIUS OF MAXIMUM WINDS (RMW) :111 KM



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

28 KT NE: 610 SE: 590 SW: 560 NW: 220

34 KT NE: 430 SE: 190 SW: 0 NW: 0







7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1200 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : UNKNOWN



1.B FORECASTS:

12H: 2016/01/22 00 UTC: 17.5 S / 72.5 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM

24H: 2016/01/22 12 UTC: 19.4 S / 71.2 E, MAX WIND=055 KT, SEVERE

TROPICAL STORM

36H: 2016/01/23 00 UTC: 21.3 S / 70.5 E, MAX WIND=070 KT, TROPICAL

CYCLONE

48H: 2016/01/23 12 UTC: 23.2 S / 70.5 E, MAX WIND=070 KT, TROPICAL

CYCLONE

60H: 2016/01/24 00 UTC: 24.9 S / 71.2 E, MAX WIND=065 KT, TROPICAL

CYCLONE

72H: 2016/01/24 12 UTC: 26.6 S / 72.6 E, MAX WIND=060 KT,

POST-TROPICAL DEPRESSION



2.B LONGER-RANGE OUTLOOK :

96H: 2016/01/25 12 UTC: 27.6 S / 73.2 E, MAX WIND=045 KT,

POST-TROPICAL DEPRESSION

120H: 2016/01/26 12 UTC: 28.4 S / 71.7 E, MAX WIND=040 KT,

POST-TROPICAL DEPRESSION



2.C ADDITIONAL INFORMATION:

T=CI=2.5+



OVER THE LAST 6 HOURS, CONVECTIVE CLOUDS SUMMITS HAVE WARMED,

PROBABLY BECAUSE OF THE DIURNAL CYCLE. IN THE MEANTIME, A CLOUD BAND

HAS SPREAD IN THE SOUTHERN SEMI-CIRCLE, WHILE WRAPPING AROUND THE

CENTER. AT 09Z, THE SYSTEM HAS BEEN UPGRATED TO THE MODERATE TROPICAL

STORM STAGE AND NAMED CORENTIN BY THE METEOROLOGICAL NATIONAL SERVICE

OF MAURITIUS. THE LOW LEVEL CENTER IS STILL DIFFICULT TO LOCATE

PRECISELY BUT ITS STRUCTURE IS IMPROVING. 0344Z AND 0430Z ASCAT

SWATHS COVER THE EASTERN HALF OF THE CIRCULATION AND SHOW WINDS

RANGING FROM 40 TO 45KT, ON A SIGNIFICANT PART OF THE CIRCULATION.

THE UPPER LEVEL DIVERGENCE IS IMPRESSIVE ON THE EQUATORIAL SIDE AND

WELL ILLUSTRATED BY THE CIRRUS CLOUDS. THIS ANALYSIS IS TAKING INTO

ACCOUNT THE ASCAT WIND DATA AND IS A LITTLE BIT HIGHER THAN DVORAK

ANALYSIS ALONE.



OVER THE NEXT 24 HOURS, CORENTIN IS LIKELY TO TRACK SOUTH-WESTWARD,

OVER THE NORTH-WESTERN EDGE OF THE LOW TO MID-TROPOSPHERIC RIDGE.

WHILE REMAINING UNDER A CELL OF UPPER LEVEL HIGH GEOPOTENTIALS, THE

SYSTEM SHOULD DEEPEN STEADILY WITHOUT ANY PARTICULAR ENVIRONMENTAL

CONSTRAINTS.



TOMORROW, WITH THE STRENGTHENING OF THE UPPER LEVEL OUTFLOW CHANNEL

ON THE SOUTHERN SIDE, AHEAD OF A POLAR TROUGH, THE LOW COULD DRAW

BENEFIT FROM EVEN BETTER UPPER LEVEL ENVIRONMENTAL CONDITIONS AND

DEEPEN QUITE RAPIDLY. CONSEQUENTLY, IT SHOULD BE STEERED BY THE

MID-LEVEL RIDGE IN ITS EAST, AND TRACK SOUTH-WESTWARD ON FRIDAY, THEN

BEND SOUTH TO SOUTH-SOUTH-EASTWARD ON SATURDAY.



FROM SUNDAY, AHEAD OF AN UPPER TROUGH, THE NORTH-WESTERLY VERTICAL

WIND SHEAR SHOULD INCREASE AND THE OHC DECREASE SOUTH OF 27S. THE LOW

MAY WEAKEN AND BEGIN AN EXTRATROPICAL TRANSITION FROM SUNDAY EVENING.

THE WEAKENED SYSTEM MAY MOVE TEMPORARILY WESTWARD OVER THE NORTHERN

SIDE OF THE SUBTROPICAL ANTICYCLONE BUILDING IN ITS SOUTH.



THIS FORECAST IS BASED ON THE AVAILABLE NWP MODELS, IN RATHER GOOD

AGREEMENT.=