Image by Sat24 As we mentioned in our previous post,
So we’re into the summer season now and with the summer season comes an increase in tropical activity off the east coast of South Africa. These summer cyclones that occur usually don’t have an effect on South African weather and tend to move south before approaching the S.A coast line, though is not always the case and storms like Eline in 2000 which made landfall in Mozambique. There have been a handful of cyclones which have had at least some impact on South African weather in the past.
Currently there is a subtropical depression off the far east coast of South Africa which is forecast by the computer models to move in a generally WNW motion over the next day or so and make landfall in Mozambique. Now I feel it is important that I make the point that forecasts change all the time and one can’t pinpoint landfall or intensity with full success. But I don’t expect it to make a direct landfall with South Africa, that is to say, I agree with the official Meteo France forecasts as they are one of the best providers of tropical forecasts for the Southern Indian ocean.
As it stands at the moment, the storm is forecast to strengthen prior to making landfall and then impact as a moderate tropical storm. Dando has the potential to bring some heavy rain to the northern parts of South Africa, though a lot will depend on the landfall position. I urge no one to turn this storm into another alarmist viral e-mail and give the Government reason to pass the recent amendments bill, there is no reason to be alarmed at this stage, though interests along the far north east coast are advised to at least keep an eye on updates. Though personally I expect the impact for South Africa to be limited to the potential for the outer bands to go over South African soil and not too see much action from Dando apart from rain and maritime related issues.
The storm itself is not forecast to get very strong and maximum windspeeds forecast at 45kt, something we see here occasionally in the Cape with strong cold fronts, so assuming it stays on the current track, S.A shouldn’t really feel any of the wind effects. But definitely keep an eye on it in the far northern parts of South Africa, as I feel that there may be some rainfall associated with it over the coming days and it has the potential to be heavy rains and possible flooding, though again – this depends a lot on how the storm evolves and where it makes landfall. But worth keeping an eye on.
The latest forecast is as follows:
632 WTIO30 FMEE 151231 RSMC / TROPICAL CYCLONE CENTER / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER: 3/6/20112012 1.A SUBTROPICAL DEPRESSION 6 2.A POSITION 2012/01/15 AT 1200 UTC: WITHIN 30 NM RADIUS OF POINT 27.5 S / 38.8 E (TWENTY SEVEN DECIMAL FIVE DEGREES SOUTH AND THIRTY EIGHT DECIMAL EIGHT DEGREES EAST) MOVEMENT : WEST 15 KT 3.A DVORAK ANALYSIS: NIL 4.A CENTRAL PRESSURE: 998 HPA 5.A MAX AVERAGE WIND SPEED (10 MN): 35 KT RADIUS OF MAXIMUM WINDS (RMW) :NIL 6.A EXTENSION OF WIND BY QUADRANTS (KM): 28 KT NE: 60 SE: 240 SW: 370 NW: 60 34 KT NE: SE: 90 SW: 90 NW: 7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 400 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : SHALLOW 1.B FORECASTS: 12H: 2012/01/16 00 UTC: 26.4 S / 36.0 E, MAX WIND=040 KT, SUBTROPICAL DEPRESSION 24H: 2012/01/16 12 UTC: 25.3 S / 34.1 E, MAX WIND=045 KT, MODERATE TROPICAL STORM 36H: 2012/01/17 00 UTC: 24.4 S / 32.7 E, MAX WIND=020 KT, INLAND 48H: 2012/01/17 12 UTC: 23.7 S / 32.0 E, MAX WIND=020 KT, INLAND 2.B LONGER-RANGE OUTLOOK : 2.C ADDITIONAL INFORMATIONS: LAST ANIMATED PICTURES DEPICT CONVECTION CLOSER TO THE CENTER IN THE NORTH-EASTERN QUADRANT. ASCAT DATA AT 0700Z SHOW GALE FORCE WINDS IN THE SOUTHERN SEMI-CIRCLE. THE WINDFIELD STRUCTURE IS ASSYMETRIC IN RELATION WITH THE GRAIENT EFFECT WITH THE SUBTROPICAL HIGH PRESSURES. SYSTEM IS TRACKING WESTWARD AT ABOUT 15KT. FOR THE NEXT 24 HOURS, NWP MODELS ARE IN FAIRLY GOOD AGREEMENT FOR A SLIGHT SLOWDOWN AND A TRACK CURVING NORTH-WESTWARD. ACTUALLY SYSTEM IS UNDER THE STEERING INFLUENCE OF THE LOW TO MID-LEVEL STRENGTHENING HIGH PRESSURES CENTERED OVER SOUTH OF SOUTH-AFRICA. CONSEQUENTLY, SYSTEM IS FORECAST TO MAKE LANDFALL ON THE COAST OF THE SOUTH MOZAMBIQUE BY ABOUT 24H TAU. ON ITS TRACK, SYSTEM IS EXPECTED TO ENCOUNTER GOOD ENVIRONMENTAL CONDTIONS FOR INTENSIFICATION AND SHOULD TAKE A TROPICAL STRUCTURE BEFORE THE LANDFALL : FAVORABLE OCEANIC HEAT CONTENT, GOOD EAST AND SOUTH LOW LEVEL CONVERGENCE, GOOD UPPER LEVEL DIVERGENCE WITH AN POLEWARD OUTFLOW. MOST OF THE AVALAIBLE NWP MODELS ARE IN GOOD AGREEMENT FOR INTENSIFICATION OF THE SYSTEM BEFORE ITS LANDFALL THAT IS CURRENTLY FORECASTED AT THE MAXIMUM STAGE OF MODERATE TROPICAL STORM IN THE BAY OF MAPUTO.=
Navigation can be hard with language difference, but http://www.meteo.fr offers updated cyclonic information.