• Indian-S: TD 14 W6 (91S)

    From Weather Alert@21:1/175 to All on Fri Mar 5 19:00:00 2021
    WTIO30 FMEE 051849
    RSMC / TROPICAL CYCLONE CENTER / LA REUNION
    TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

    0.A WARNING NUMBER: 6/14/20202021
    1.A OVERLAND DEPRESSION 14

    2.A POSITION 2021/03/05 AT 1800 UTC:
    WITHIN 20 NM RADIUS OF POINT 18.5 S / 46.0 E
    (EIGHTEEN DECIMAL FIVE DEGREES SOUTH AND
    FORTY SIX DECIMAL ZERO DEGREES EAST)
    MOVEMENT: EAST-SOUTH-EAST 15 KT

    3.A DVORAK ANALYSIS: NIL
    4.A CENTRAL PRESSURE: 1004 HPA
    5.A MAX AVERAGE WIND SPEED (10 MN): 20 KT
    RADIUS OF MAXIMUM WINDS (RMW): NIL

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

    7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 300 KM
    8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

    1.B FORECASTS (WINDS RADII IN KM):
    12H: 2021/03/06 06 UTC: 19.4 S / 49.0 E, VENT MAX= 020 KT, OVERLAND
    DEPRESSION

    24H: 2021/03/06 18 UTC: 21.0 S / 51.9 E, VENT MAX= 030 KT, TROPICAL
    DISTURBANCE
    28 KT NE: 45 SE: 20 SW: 10 NW: 85

    36H: 2021/03/07 06 UTC: 22.6 S / 54.3 E, VENT MAX= 035 KT, MODERATE
    TROPICAL STORM
    28 KT NE: 85 SE: 75 SW: 55 NW: 75
    34 KT NE: 75 SE: 65 SW: 45 NW: 65

    48H: 2021/03/07 18 UTC: 24.0 S / 56.9 E, VENT MAX= 035 KT, MODERATE
    TROPICAL STORM
    28 KT NE: 85 SE: 95 SW: 85 NW: 75
    34 KT NE: 75 SE: 85 SW: 75 NW: 65

    60H: 2021/03/08 06 UTC: 25.4 S / 58.4 E, VENT MAX= 030 KT,
    POST-TROPICAL DEPRESSION
    28 KT NE: 45 SE: 35 SW: 75 NW: 95

    72H: 2021/03/08 18 UTC: 27.1 S / 60.6 E, VENT MAX= 030 KT,
    POST-TROPICAL DEPRESSION
    28 KT NE: 10 SE: 150 SW: 100 NW: 55

    2.B LONGER-RANGE OUTLOOK:
    96H: 2021/03/09 18 UTC: 29.9 S / 64.5 E, VENT MAX= 025 KT, FILLING UP

    120H: 2021/03/10 18 UTC: 29.2 S / 64.5 E, VENT MAX= 020 KT, REMNANT
    LOW

    2.C ADDITIONAL INFORMATION:
    THE SYSTEM KEEPS ON TRACKING OVER LAND. CONVECTION REMAINS ACTIVE
    NEAR THE CIRCULATION CENTER, HWICH SEEMS TO KEEP A RATHER GOOD
    COHERENCE FOR NOW. DIVERGENCE REMAINS EXCELLENT POLEWARD.

    THE SYSTEM SHOULD COME BACK OVER SEA SOUTH OF TAMATAVE TOMORROW
    SATURDAY IN THE LATE MORNING, BEFORE TRACKING SOUTH-EASTWARDS AHEAD
    OF A MID-LATITUDES TROUGH. THE MAJORITY OF THE AVAILABLE GUIDANCE
    SUGGEST A PASSAGE AT MORE THAN 100 KM IN THE SOUTH-WEST OF REUNION
    ISLAND SUNDAY MORNING, EVEN IF MEDIUM UNCERTAINTY REMAINS ON THE
    EXACT TRACK. EARLY NEXT WEEK, THE SYSTEM SHOULD BE CAPTURED BY A
    MID-LATITUDES TROUGH WHICH SHOULD BRING IT SOUTH OF 25S, FAR FROM THE
    INHABITED ISLANDS, ALONG A SOUTH-EASTWARDS THEN SOUTH-SOUTH-EASTWARDS
    TRACK. AT THE END OF THE TAUS, THE RESIDUAL DEPRESSION COULD BE
    TRAPPED NORTH OF 30S WITH THE ARRIVAL OF A NEW HIGH PRESSURE CELL
    FROM THE WEST.

    AS IT WILL COME BACK OVER SEA TOMORROW, THE SYSTEM SHOULD ENCOUNTER
    CONDITIONS THAT SHOULD BECOME GRADUALLY MORE BAROCLINIC IN
    INTERACTION WITH A BRANCH OF THE SUBTROPICAL JET. AT FIRST, THE
    SYSTEM SHOULD INTENSIFY AND COULD REACH THE MODERATE TROPICAL STORM
    STAGE BY SUNDAY AS IT TRACKS RAPIDLY IN THE SAME DIRECTION AS THE MID
    AND UPPER FLOWS. FROM MONDAY, THE INCREASE OF THE SHEAR AND THE
    PASSAGE OVER COOLER WATERS SHOULD MAKE THE SYSTEM EVOLVE INTO A
    POST-TROPICAL LOW.

    IN TERMS OF IMPACTS ON MADAGASCAR, RAINFALL OVER THE NEXT 24HRS CLOUD
    REACH 100 TO 150 MM LOCALLY OVER THE CENTER-WESTERN PART OF THE
    COUNTRY AND FAR INLAND.

    FOR THE MASCARENES ISLANDS, A SIGNIFICANT BUT BRIEF WEATHER
    DEGRADATION IN TERMS OF RAINFALL AND WIND GUSTS IS EXPECTED BETWEEN
    SATURDAY EVENING AND SUNDAY MORNING.
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