• Indian-S: TC Habana W40

    From Weather Alert@21:1/175 to All on Sat Mar 13 09:59:00 2021
    WTIO30 FMEE 131301
    RSMC / TROPICAL CYCLONE CENTER / LA REUNION
    TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

    0.A WARNING NUMBER: 40/13/20202021
    1.A TROPICAL CYCLONE 13 (HABANA)

    2.A POSITION 2021/03/13 AT 1200 UTC:
    WITHIN 20 NM RADIUS OF POINT 21.2 S / 70.1 E
    (TWENTY ONE DECIMAL TWO DEGREES SOUTH AND
    SEVENTY DECIMAL ONE DEGREES EAST)
    MOVEMENT: SOUTH-SOUTH-WEST 6 KT

    3.A DVORAK ANALYSIS: 4.5/4.5/S 0.0/6 H

    4.A CENTRAL PRESSURE: 965 HPA
    5.A MAX AVERAGE WIND SPEED (10 MN): 80 KT
    RADIUS OF MAXIMUM WINDS (RMW): 65 KM

    6.A EXTENSION OF WIND BY QUADRANTS (KM):
    28 KT NE: 205 SE: 295 SW: 260 NW: 205
    34 KT NE: 165 SE: 205 SW: 205 NW: 150
    48 KT NE: 110 SE: 155 SW: 160 NW: 110
    64 KT NE: 95 SE: 110 SW: 110 NW: 95

    7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1009 HPA / 900 KM
    8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

    1.B FORECASTS (WINDS RADII IN KM):
    12H: 2021/03/14 00 UTC: 21.6 S / 70.2 E, VENT MAX= 075 KT, TROPICAL
    CYCLONE
    28 KT NE: 205 SE: 295 SW: 280 NW: 175
    34 KT NE: 150 SE: 195 SW: 185 NW: 140
    48 KT NE: 95 SE: 95 SW: 95 NW: 75
    64 KT NE: 55 SE: 75 SW: 75 NW: 55

    24H: 2021/03/14 12 UTC: 21.6 S / 70.5 E, VENT MAX= 065 KT, TROPICAL
    CYCLONE
    28 KT NE: 195 SE: 285 SW: 260 NW: 165
    34 KT NE: 150 SE: 195 SW: 165 NW: 110
    48 KT NE: 65 SE: 85 SW: 85 NW: 45
    64 KT NE: 55 SE: 65 SW: 65 NW: 35

    36H: 2021/03/15 00 UTC: 21.3 S / 70.5 E, VENT MAX= 050 KT, SEVERE
    TROPICAL STORM
    28 KT NE: 155 SE: 295 SW: 285 NW: 175
    34 KT NE: 130 SE: 195 SW: 185 NW: 95
    48 KT NE: 65 SE: 75 SW: 95 NW: 35

    48H: 2021/03/15 12 UTC: 20.9 S / 69.6 E, VENT MAX= 040 KT, MODERATE
    TROPICAL STORM
    28 KT NE: 95 SE: 240 SW: 305 NW: 110
    34 KT NE: 85 SE: 165 SW: 175 NW: 85

    60H: 2021/03/16 00 UTC: 20.6 S / 68.0 E, VENT MAX= 035 KT, MODERATE
    TROPICAL STORM
    28 KT NE: 95 SE: 175 SW: 250 NW: 55
    34 KT NE: 85 SE: 120 SW: 120 NW: 35

    72H: 2021/03/16 12 UTC: 20.7 S / 66.6 E, VENT MAX= 030 KT, FILLING UP
    28 KT NE: 95 SE: 85 SW: 140 NW: 55
    34 KT NE: 85 SE: 65 SW: 65 NW: 35

    2.B LONGER-RANGE OUTLOOK:
    96H: 2021/03/17 12 UTC: 21.0 S / 64.0 E, VENT MAX= 030 KT, FILLING UP
    28 KT NE: 20 SE: 75 SW: 55 NW: 55

    120H: 2021/03/18 12 UTC: 21.0 S / 61.5 E, VENT MAX= 025 KT, FILLING
    UP

    2.C ADDITIONAL INFORMATION:
    T=4.5- CI=4.5

    DURING THE LAST SIX HOURS, HABANA HAS MAINTAINED AN EMBEDDED CENTER
    PATTERN WITH CLOUD TOPS THAT HAVE WARMED UP. THE 0847Z AMSR2
    MICROWAVE IMAGES SHOWED A WELL CONSOLIDATED EYEWALL BUT STILL
    WEAKENED IN THE NORTHEASTERN PART. THE COMPARISON BETWEEN THE 37GHZ
    AND 91GHZ IMAGE DOES NOT YET FULLY ARGUE FOR A TILT OF THE UPPER WARM
    CORE DUE TO THE MID-TROPOSPHERE SHEAR CONSTRAINT CURRENTLY OPERATING
    WITHIN THE SYSTEM. THE FINAL INTENSITY ESTIMATED AT 80 KT IS SLIGHTLY
    HIGHER THAN THE SUBJECTIVE DVORAK ESTIMATE. THIS ESTIMATE IS BASED ON
    A CONSENSUS OF THE LATEST OBJECTIVE ANALYSES (AMSU, ATMS AND SSMIS
    DATA).

    HABANA IS NOW MOVING ON A MERIDIAN TRACK AT THE WESTERN EDGE OF THE
    SUBTROPICAL RIDGE AND IN FRONT OF A WEAKNESS GENERATED BY THE PASSAGE
    OF A TROUGH FURTHER SOUTH. HABANA'S MOVEMENT SHOUD SLOW DOWN ON THIS
    EVENING, AND THEN ON SUNDAY, THE STEERING FLOWS WILL BECOME VERY
    WEAK, LEADING TO A QUASI-STATIONNARY MOVEMENT (SLOW EASTWARDS DRIFT
    EXPECTED). FROM MONDAY, MOST NWP MODELS AGREE ABOUT A NORTHWESTWARDS
    AND THEN WESTWARDS TRACK, UNDER THE STEERING INFLUENCE OF A BUILDING
    LOW TO MID TROPOSPHERE SUBTROPICAL RIDGE TO ITS SOUTH-WEST. THE
    SYSTEM, WHICH SHOULD THEN BE IN THE PROCESS OF FILLING, WILL THEN
    MOVE IN GENERALLY WESTWARDS ON THE NORTHERN EDGE OF THIS RIDGE.
    RSMC'S FORECAST IS BASED ON A COMPROMISE BETWEEN THE BEST AVAILABLE
    GUIDANCE.

    IN TERMS OF INTENSITY FORECAST, THE ENVIRONMENTAL CONDITIONS HAVE
    ALREADY DETERIORATED AND WILL BECOME MORE AND MORE UNFAVORABLE DURING
    THE WEEKEND WITH A WELL-ESTABLISHED MID-TROPOSPHERE SHEAR, BRINGING
    DRY AIR GRADUALLY TO THE CORE OF THE SYSTEM, ERODING THEN DESTROYING
    THE UPPER LEVELS WARM CORE. AT THE BEGINNING OF NEXT WEEK, IN A STILL UNFAVORABLE ENVIRONMENT DUE TO DRY AIR, HABANA SHOULD BECOME A WEAK
    TO VERY WEAK SYSTEM.

    FROM NEXT TUESDAY, THE REMNANT OF HABANA SHOULD APPROACH THE
    RODRIGUES ISLAND WITHOUT ANY PARTICULAR CONSEQUENCE IN TERMS OF WINDS
    OR RAIN. EASTERLY SWELL GENERATED BY HABANA HAS ALREADY PROPAGATED TO
    THE MASCAREIGNES ISLANDS AND WILL LAST DURING THE FIRST PART OF NEXT
    WEEK.
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