#2 Postby wxman57 » Tue Mar 07, 2017 10:16 am
Tropical Depression 7 now, officially. However, satellite indicates it may now be a TS. Waiting for ASCAT pass to confirm.
ZCZC 639
WTIO30 FMEE 071247
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 4/7/20162017
1.A TROPICAL DEPRESSION 7
2.A POSITION 2017/03/07 AT 1200 UTC:
WITHIN 25 NM RADIUS OF POINT 15.9 S / 72.5 E
(FIFTEEN DECIMAL NINE DEGREES SOUTH AND SEVENTY TWO DECIMAL
FIVE DEGREES EAST)
MOVEMENT : WEST 8 KT
3.A DVORAK ANALYSIS: 2.5/2.5/D 0.5/12 H
4.A CENTRAL PRESSURE: 1001 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW) :46 KM
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: SE: 220 SW: 150 NW:
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP
1.B FORECASTS:
12H: 2017/03/08 00 UTC: 15.7 S / 70.9 E, MAX WIND=035 KT, MODERATE
TROPICAL STORM
24H: 2017/03/08 12 UTC: 15.5 S / 69.6 E, MAX WIND=035 KT, MODERATE
TROPICAL STORM
36H: 2017/03/09 00 UTC: 15.5 S / 68.4 E, MAX WIND=040 KT, MODERATE
TROPICAL STORM
48H: 2017/03/09 12 UTC: 15.7 S / 67.7 E, MAX WIND=040 KT, MODERATE
TROPICAL STORM
60H: 2017/03/10 00 UTC: 16.2 S / 67.1 E, MAX WIND=035 KT, MODERATE
TROPICAL STORM
72H: 2017/03/10 12 UTC: 17.6 S / 66.2 E, MAX WIND=030 KT, TROPICAL
DEPRESSION
2.B LONGER-RANGE OUTLOOK :
96H: 2017/03/11 12 UTC: 20.9 S / 62.0 E, MAX WIND=025 KT, TROPICAL
DISTURBANCE
120H: 2017/03/12 12 UTC: 23.6 S / 54.7 E, MAX WIND=035 KT, MODERATE
TROPICAL STORM
2.C ADDITIONAL INFORMATION:
T=CI=2.5
OVER THE LAST 6 HOURS, THE "MIDGET" PATTERN SEEM TO CONFIRM WITH A
SMALL AND CONCENTRATED CONVECTIVE CORE. A FEW CONVECTIVE BANDS
WRAPPED TEMPORARILY AROUND THE CENTER BUT DID NOT MAINTAINED. 0757Z
AMSR2 SWATH SHOW A NICE LOW LEVEL ORGANISATION BUT 0947Z SSMI DATA DO
NOT CONFIRM THIS STRUCTURE IMPROVEMENT.
THE LOW IS MOVING WESTWARDS STEERED BY THE LOW/MID LEVEL SUBTROPICAL
RIDGE LOCATED ON THE SOUTH-EASTERN PART OF THE BASIN. TOMORROW, THE
SYSTEM IS EXPECTED TO SLOW DOWN UNDER THE INFLUENCE OF A RIDGE AXED
BETWEEN IT AND ENAWO. FROM FRIDAY, THE SYSTEM SHOULD BEGIN TO
ACCELERATE WHILE DIVING SOUTHWESTWARD IN THE WAKE OF ENAWO'S RESIDUAL
CLOCKWISE CIRCULATION. DIFFERENCES IN THE TIMING OF THIS TURN ARE THE
MAIN CAUSE OF THE MODERATE GUIDANCE DISPERSION.
ON THIS TRACK, ENVIRONMENTAL CONDITIONS REMAIN NEUTRAL TO SLIGHTLY
CONDUCIVE BEFORE BECOMING UNFAVOURABLE FROM THURSDAY. LOW LEVEL
SUPPLY IS VERY EFFICIENT POLEWARD BUT REMAINS VERY WEAK EQUATORWARD.
IN THE UPPER LEVELS, THE SYSTEM IS LOCATED UNDER THE NARROW
SUBTROPICAL RIDGE AND CURRENTLY BENEFITS FROM A GOOD DIVERGENCE. FROM
THURSDAY NIGHT, THE ARRIVAL OF AN UPPER-TROUGH FROM THE MID-LATITUDES
(ROSSBY WAVE BREAKING) IS PRODUCING A NORTHERLY MODERATE SHEAR OVER
THE SYSTEM. HOWEVER, THE POLEWARD DIVERGENCE AND THE MOTION OF THE
SYSTEM SHOULD SLOW THE WEAKENING. AT THE END OF THE TAUS, WITH THE
DISSIPATION OF THE UPPER TROUGH, CONDITIONS COULD BECOME MORE
CONDUCIVE AGAIN DESPITE THE COOLER SEA SURFACE.=
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