SIO: CHEDZA

[jaguarjace]

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 19.8S
39.3E, IS NOW LOCATED NEAR 18.1S 40.7E, APPROXIMATELY 360 NM WEST OF
ANTANANARIVO, MADAGASCAR. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS A BROAD AND POORLY DEFINED LOW-LEVEL CIRCULATION
CENTER (LLCC) WITH FRAGMENTED DEEP CONVECTIVE BANDING OVER THE
EASTERN SEMI-CIRCLE. A 150644Z AMSU-B MICROWAVE IMAGE SHOWS A BROAD
LLCC WITH DEEP CONVECTION CONTAINED TO THE EASTERN PERIPHERIES.
UPPER-LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH MODERATE
TO STRONG VERTICAL WIND SHEAR (20 TO 30 KNOTS) WHICH IS BEING
SLIGHTLY OFFSET BY GOOD POLEWARD OUTFLOW. DYNAMIC GUIDANCE HAS
BECOME MORE AGGRESSIVE WITH DEVELOPMENT OVER THE NEXT 48 HOURS AS
THE SYSTEM TRACKS TOWARD WESTERN MADAGASCAR. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO MEDIUM.

[jaguarjace]

ZCZC 991
WTIO30 FMEE 150629
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 5/6/20142015
1.A TROPICAL DISTURBANCE 6
2.A POSITION 2015/01/15 AT 0600 UTC:
WITHIN 20 NM RADIUS OF POINT 18.1 S / 40.9 E
(EIGHTEEN DECIMAL ONE DEGREES SOUTH AND FORTY DECIMAL NINE
DEGREES EAST)
MOVEMENT : NORTH-NORTH-EAST 5 KT
3.A DVORAK ANALYSIS: 1.5/1.5/S 0.0/0 H
4.A CENTRAL PRESSURE: 997 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 25 KT
RADIUS OF MAXIMUM WINDS (RMW) :NIL
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: SE: SW: 240 NW:
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1004 HPA / 700 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : SHALLOW
1.B FORECASTS:
12H: 2015/01/15 18 UTC: 19.2 S / 42.9 E, MAX WIND=030 KT, TROPICAL
DEPRESSION
24H: 2015/01/16 06 UTC: 20.2 S / 44.2 E, MAX WIND=040 KT, MODERATE
TROPICAL STORM
36H: 2015/01/16 18 UTC: 21.2 S / 45.5 E, MAX WIND=020 KT, INLAND
48H: 2015/01/17 06 UTC: 22.3 S / 48.7 E, MAX WIND=025 KT, TROPICAL
DISTURBANCE
60H: 2015/01/17 18 UTC: 22.0 S / 51.4 E, MAX WIND=025 KT, TROPICAL
DISTURBANCE
72H: 2015/01/18 06 UTC: 21.9 S / 53.1 E, MAX WIND=030 KT, TROPICAL
DEPRESSION
2.B LONGER-RANGE OUTLOOK :
96H: 2015/01/19 06 UTC: 22.0 S / 55.5 E, MAX WIND=030 KT, TROPICAL
DEPRESSION
120H: 2015/01/20 06 UTC: 22.6 S / 56.6 E, MAX WIND=030 KT, TROPICAL
DEPRESSION
2.C ADDITIONAL INFORMATIONS:
T AND CI=1.5+
THE LOW LEVEL CENTRE IS EXPOSED NORTH-WEST OF THE CONVECTION THAT IS
ORGANIZING AND INTENSIFYING WITHIN THE EASTERN PART OF THE SYSTEM.
UNDER THE STEERING INFLUENCE OF A MID-LEVEL RIDGE IN ITS NORTH, THE
SYSTEM IS EXPECTED TO TRACK GENERALLY EAST-SOUTH-EASTWARD WITHIN THE
NEXT DAYS.
ON THIS FORECAST TRACK, ENVIRONMENTAL CONDITIONS ARE RATHER GOOD FOR
THE NEXT 24 HOURS, WITH A WEAK VERTICAL WIND-SHEAR AN WARM SST. UPPER
LEVEL DIVERGENCE REMAINS HOWEVER LIMITED. THIS SYSTEM SHOULD
INTENSIFY UNTIL ITS LANDFALL OVER THE WESTERN MADAGASCAR SHORELINE
EXPECTED ON FRIDAY MORNING. THE LAST ECMWF RUN (00Z) SUGGESTS A RAPID
INTENSIFICATION BEFORE THIS LANDFALL.
THE MID LEVEL CIRCULATION SHOULD RESIST TO THE CROSSING PATH OVER
MADAGASCAR AND THE LOW LEVEL CIRCULATION IS LIKELY TO DEVELOP OVERSEA
EAST OF MADAGASCAR ON SATURDAY. ENVIRONMENTAL CONDITIONS ARE NOT
EXPECTED TO BE ANOUGH FAVOURABLE FOR FURTHER IMPORTANT
INTENSIFICATION, OWING TO A PERSISTENT UPPER LEVEL WESTERLY TO
NORTH-WESTERLY VERTICAL WIND-SHEAR ALOFT.=
NNNN

[wxman57]

Quite a few 40-45kt winds around the well-defined center of this "depression". ASCAT has indicated 35kt winds for over 24 hrs:

[jaguarjace]

ZCZC 655
WTIO30 FMEE 151913
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 7/6/20142015
1.A TROPICAL DEPRESSION 6
2.A POSITION 2015/01/15 AT 1800 UTC:
WITHIN 30 NM RADIUS OF POINT 19.3 S / 42.3 E
(NINETEEN DECIMAL THREE DEGREES SOUTH AND FORTY TWO DECIMAL THREE DEGREES EAST)
MOVEMENT : EAST-SOUTH-EAST 7 KT
3.A DVORAK ANALYSIS: 2.5/2.5/D 1.0/24 H
4.A CENTRAL PRESSURE: 994 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW) :NIL
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 300 SE: 300 SW: 220 NW: 150
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1003 HPA / 700 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MEDIUM
1.B FORECASTS:
12H: 2015/01/16 06 UTC: 19.6 S / 43.4 E, MAX WIND=035 KT, MODERATE TROPICAL STORM
24H: 2015/01/16 18 UTC: 20.4 S / 44.9 E, MAX WIND=030 KT, INLAND
36H: 2015/01/17 06 UTC: 21.3 S / 47.8 E, MAX WIND=020 KT, INLAND
48H: 2015/01/17 18 UTC: 21.6 S / 49.9 E, MAX WIND=025 KT, TROPICAL DISTURBANCE
60H: 2015/01/18 06 UTC: 21.9 S / 51.8 E, MAX WIND=030 KT, TROPICAL DEPRESSION
72H: 2015/01/18 18 UTC: 22.0 S / 52.9 E, MAX WIND=035 KT, MODERATE TROPICAL STORM
2.B LONGER-RANGE OUTLOOK :
96H: 2015/01/19 18 UTC: 23.2 S / 54.7 E, MAX WIND=030 KT, POST-TROPICAL DEPRESSION
120H: 2015/01/20 18 UTC: 25.0 S / 55.4 E, MAX WIND=030 KT, POST-TROPICAL DEPRESSION
2.C ADDITIONAL INFORMATIONS:
T=CI=2.5
SYSTEM KEEPS ON INTENSIFYING AND UNDER THE STEERING INFLUENCE OF A MID-LEVEL RIDGE IN ITS NORTH, I
T IS EXPECTED TO TRACK GENERALLY EAST-SOUTH-EASTWARD WITHIN THE NEXT DAYS.
ON THIS FORECAST TRACK, FOR THE NEXT 24 HOURS, THE LOW LEVEL CONVERGENCE IS GOOD WHILE THE SYSTEM
IS SITUATED UNDER THE NORTHERN EXTREMITY OF AN UPPER LEVEL TROUGH WITH A RATHER WEAK VERTICAL WIND
-SHEAR. IT IS DIFFICULT TO DETERMINE THE IMPACT OF THIS TROUGH FOR THE EVOLUTION OF THE SYSTEM, BU
T IT SHOULD FAVOUR THE CONVECTION AND A GOOD DIVERGENCE SOUTH-EASTWARD.
SO THIS SYSTEM SHOULD INTENSIFY UNTIL ITS LANDFALL OVER THE WESTERN MADAGASCAR SHORELINE EXPECTED
ON FRIDAY AFTERNOON OR EVENING.THE UNCERTAINTY IS HIGH FOR INTENSITY FORECAST BEFORE THE LANDFALL.
THE MID LEVEL CIRCULATION SHOULD RESIST TO THE CROSSING PATH OVER MADAGASCAR AND THE LOW LEVEL CIR
CULATION IS LIKELY TO DEVELOP OVERSEA EAST OF MADAGASCAR ON SATURDAY. ENVIRONMENTAL CONDITIONS ARE
NOT EXPECTED TO BE ENOUGH FAVOURABLE FOR FURTHER IMPORTANT INTENSIFICATION, OWING TO A PERSISTENT
UPPER LEVEL WESTERLY TO NORTH-WESTERLY VERTICAL WIND-SHEAR ALOFT. BUT EVEN, A HIGH UNCERTAINTY EX
ISTS FOR INTENSITY AND TRACK FORECAST AT THIS TERM.
NNNN

[jaguarjace]

ZCZC 457
WTIO30 FMEE 160054
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 8/6/20142015
1.A MODERATE TROPICAL STORM 6 (CHEDZA)
2.A POSITION 2015/01/16 AT 0000 UTC:
WITHIN 30 NM RADIUS OF POINT 19.3 S / 43.4 E
(NINETEEN DECIMAL THREE DEGREES SOUTH AND FORTY THREE DECIMAL
FOUR DEGREES EAST)
MOVEMENT : EAST 12 KT
3.A DVORAK ANALYSIS: 3.0/3.0/D 1.5/24 H
4.A CENTRAL PRESSURE: 987 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW) :56 KM
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 280 SE: 240 SW: 220 NW: 300
34 KT NE: 90 SE: 150 SW: 150 NW: 90
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1003 HPA / 900 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MEDIUM
1.B FORECASTS:
12H: 2015/01/16 12 UTC: 19.9 S / 44.3 E, MAX WIND=050 KT, SEVERE
TROPICAL STORM
24H: 2015/01/17 00 UTC: 21.1 S / 46.3 E, MAX WIND=025 KT, INLAND
36H: 2015/01/17 12 UTC: 21.6 S / 49.0 E, MAX WIND=020 KT, DISTURBANCE
48H: 2015/01/18 00 UTC: 21.5 S / 51.2 E, MAX WIND=025 KT, TROPICAL
DISTURBANCE
60H: 2015/01/18 12 UTC: 21.7 S / 52.4 E, MAX WIND=030 KT, TROPICAL
DEPRESSION
72H: 2015/01/19 00 UTC: 22.0 S / 53.1 E, MAX WIND=035 KT, MODERATE
TROPICAL STORM
2.B LONGER-RANGE OUTLOOK :
96H: 2015/01/20 00 UTC: 23.2 S / 53.6 E, MAX WIND=040 KT, MODERATE
TROPICAL STORM
120H: 2015/01/21 00 UTC: 24.9 S / 54.4 E, MAX WIND=050 KT,
POST-TROPICAL DEPRESSION
2.C ADDITIONAL INFORMATIONS:
T=CI=3.0-
1913Z ASCAT SWATH SHOWS GALE FORCE WINDS EXTENDING OVER A LARGE PART
OF CIRCULATION IN THE SOUTHERN SEMI-CIRCLE.
DVORAK SIGNATURE CONFIRMS THAT MODERATE TROPICAL STORM STAGE HAS
PROBABLY BEEN REACHED AND CHEDZA HAS THERFORE BEEN NAMED BY THE
METEOROLOGICAL SERVICES OF MADAGASCAR.
UNDER THE STEERING INFLUENCE OF THE MID-LEVELS NEAR-EQUATORIAL RIDGE
IN ITS NORTH, SYSTEM IS GLOBALLY TRACKING EASTWARDS SINCE 12Z.
CHEDZA IS LOCATED UNDER AN UPPER-LEVEL TROUGH AXIS IN A MODERATE
SHEARED AREA AND LIMITED EQUATORWARD UPPER-LEVEL OUTFLOW.
SYSTEM INTENSIFICATION IS MAINLY LINKED TO A VERY GOOD LOW/MID LEVEL
CONVERGENCE ON ITS BOTH EDGES, HIGH OCEANIC HEAT CONTENTS OVER SEA
SURFACE TEMPERATURE AT ABOUT 29/30 DG AND A VERY GOOD POLEWARD
OUTFLOW CHANNEL ALOFT SUSTAINED BY THE SUBTROPICAL WESTERLY JET.
THIS ENVIRONMENTAL CONDITIONS ARE NOT EXPECTED TO CHANGE WITHIN THE
NEXT 12 HOURS AND A GRADUAL BUT SLOW FURTHER INTENSIFICATION IS
THEREFORE FORECAST UNTIL THE SYSTEM MAKES LANDFALL OVER THE WESTERN
MADAGASCAR COASTLINE IN THE AREA OF THE TSIRIBIHINA RIVER ESTUARY
(BETWEEN TAMBOHORANI AND BELO-SUR-MER).
MOST OF THE AVAILABLE NWP MODELS SUGGEST THAT THE MID-LEVEL
CIRCULATION COULD RESIST TO THE CROSSING PATH OVER MADAGASCAR AND
THAT THE LOW LEVEL CIRCULATION COULD RE-DEVELOP AS THE SYSTEM GET
BACK OVERSEA ON THE SOUTH-EAST OF MADAGASCAR ON SATURDAY.
ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE MARGINAL BY THAT TIME
EXPERIENCING A MODERATE WEST-NORTH-WESTERLY VERTICAL WINDSHEAR
HOWEVER WEAKENING ON SUNDAY AND IN THE SAME DIRECTION THAN THE
SYSTEM'S MOTION,
BUT AS IN THE MOZAMBIQUE CHANNEL BEFORE THE LANDFALL, IN A VERY GOOD
LOW LEVEL CONVERGENCE ENVIRONMENT OVER FAVOURABLE HEAT OCEANIC
CONTENTS AND SUSTAINED BY AN EFFICIENT POLEWARD UPPER-LEVEL OUTFLOW.
ECMWF AND GFS NWP MODELS SUGGEST A GRADUAL FURTHER INTENSIFICATION ON
A EAST-SOUTH-EASTWARDS TRACK AT FIRST.
ON AND AFTER MONDAY, A MID-LEVEL TROUGH ARRIVES IN THE SOUTH AND
CHEDZA IN THEN EXPECTED TO RECURVE SOUTH-SOUTH-EASTWARDS AND TO KEEP
ON INTENSIFY.=
NNNN

[euro6208]

06S CHEDZA 150116 0600 19.4S 43.3E SHEM 45 989

[jaguarjace]

Might peak as a Severe Tropical Storm.

[jaguarjace]

06S CHEDZA 150116 1200 19.7S 43.8E SHEM 50 985

[jaguarjace]

[euro6208]

06S CHEDZA 150117 1200 21.9S 49.0E SHEM 30 1000

[somethingfunny]

Here is a great image of Chedza and Bansi from earlier this week: