Fair warning was provided over the past odd week in
The Indian Ocean looks to be in full swing at the moment, usually the bulk of tropical development in the SW Indian occurs in late summer months February and March, though it looks like we’re off to an early start. This past week we had Tropical Depression Dando which moved westward into southern Mozambique and then whose remnants moved into South Africa where it is still causing flooding issues for some parts including Limpopo Province in particular. This storm was not very intense and wind speeds with it were below 45kt.
But we already have 2 new areas of interest in the SW Indian Ocean, one of which has the potential for effecting South African weather in a week or so. Invest 95S is located in the Mozambique Channel and has already showed signs of organization over the past several hours and to me it looks as though it may have a good opportunity to become a tropical depression and deepen further into a tropical storm or even a cyclone over the next few days. The other system is 94S which lies to the far east of Madagascar and poses less of a direct threat to the African continent in the near future.
I am guessing that 95S will develop first and go on to become Tropical Depression or Tropical Storm Ethel. The GFS model then shows Tropical Storm Ethel (currently 95S) intensifying and heading south down the channel and then moving west into what is the middle to southern parts of east Mozambique. It would be difficult to get a direct South African landfall from this angle but it is possible that after making landfall this system could then drift south and bring heavy rain to the northern parts of S.A, though this system, should it develop has the potential to impact South African weather, it looks like it would be quite probable for it to have a harsh effect on Mozambique.
The system is still in it’s early days and not yet even named, but it is definitely something to keep an eye on, at least out of interest’s sake. Model forecasts a week ahead, especially tropical ones – can be subject to a large margin of error so definitely don’t take the current track as fact as it’s likely to change assuming the storm develops.
Long range models are also showing the potential for another system in about 14 days to develop near Madagascar.
Update #1 (19 January 2012 07:00): Over the past 16 hours both Invest 94S and Invest 95S have been developing and have been upgraded to Tropical Depression 7 and Tropical Disturbance 8 respectively. With both storms developing pretty quickly it’s difficult to tell who will assume the name Tropical Storm Ethel and who will become Tropical Storm Funso. As it stands at the moment it looks as though 95S which is the storm in the Mozambique Channel may be the one to assume to the name of Funso.
95S forecasts look bullish with a 165km/h Tropical Cyclone forecast by Meteo France. This would be very dangerous, most likely to residents in Mozambique or Madagascar, depending on which way the storm moves. The GFS shows the potential for extreme flooding along the Mozambique east coast in about 5 to 6 days, and this storm has the potential to impact areas already effected this past week by SubTropical Depression Dando including the possibility for more heavy rain over northern South Africa. The current GFS run shows the storm moving into Mozambique and then heading WSW, with some impact on South African rainfall.
I will once again reiterate, these storms can change their heading easily and either be stronger or weaker, or make landfall in a different area than forecast a day or two prior. By no means should one look at these forecasts and take it as fact, every weather forecast is subject to change and I expect we will see change with this one too, but definitely worth keeping an eye on it, extreme northern South Africa could face some more flooding and if the forecast holds things look a lot worse for Mozambique.
The following is a Meteo France official forecast on 95S:
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 1/8/20112012
1.A TROPICAL DISTURBANCE 8
2.A POSITION 2012/01/19 AT 0000 UTC:
WITHIN 25 NM RADIUS OF POINT 17.7 S / 41.1 E
(SEVENTEEN DECIMAL SEVEN DEGREES SOUTH AND FORTY ONE DECIMAL ONE DEGREES EAST)
MOVEMENT : SOUTH-WEST 4 KT
3.A DVORAK ANALYSIS: 2.0/2.0/D 0.5/18 H
4.A CENTRAL PRESSURE: 1001 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):
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1005 HPA / 500 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MEDIUM
12H: 2012/01/19 12 UTC: 18.1 S / 40.6 E, MAX WIND=025 KT, TROPICAL DISTURBANCE
24H: 2012/01/20 00 UTC: 18.4 S / 39.4 E, MAX WIND=030 KT, TROPICAL DEPRESSION
36H: 2012/01/20 12 UTC: 18.5 S / 38.6 E, MAX WIND=035 KT, MODERATE TROPICAL STORM
48H: 2012/01/21 00 UTC: 18.5 S / 37.9 E, MAX WIND=040 KT, MODERATE TROPICAL STORM
60H: 2012/01/21 12 UTC: 18.7 S / 37.8 E, MAX WIND=045 KT, MODERATE TROPICAL STORM
72H: 2012/01/22 00 UTC: 18.9 S / 38.1 E, MAX WIND=055 KT, SEVERE TROPICAL STORM
2.B LONGER-RANGE OUTLOOK :
96H: 2012/01/23 00 UTC: 19.0 S / 39.4 E, MAX WIND=070 KT, TROPICAL CYCLONE
120H: 2012/01/24 00 UTC: 21.2 S / 39.4 E, MAX WIND=080 KT, TROPICAL CYCLONE
2.C ADDITIONAL INFORMATIONS:
CONVECTION HAS BUILT NEAR THE CENTRE DURING THE LAST HOURS.
1834Z ASCAT SWATH SHOWS NOW MAXIMUM WINDS AT ABOUT 20/25 KT WITHIN A WELL DEFINED CLOCKWISE CIRCUL
EUROPEANS NWP MODELS (ECMWF, UKMO, ARPEGE) AND ALSO AVNO ARE IN GOOD AGREEMENT FOR A GLOBALLY SOUT
HWESTWARDS FORECAST TRACK UP TO TAU 48 TO 60 HOURS AND THEN A SOUTHEASTWARDS TRACK.
OVER THIS TRACK, ENVIRONMENTAL CONDITIONS ARE VERY FAVOURABLE FOR REGULAR FURTHER DEVELOPMENT WITH
A GOOD LOW LEVEL INFLOW ON THE BOTH SIDES, WEAK VERTICAL WIND SHEAR, WELL SUSTAINED BY TWO UPPER
LEVEL OUTFLOW CHANNELS, HEAT POTENTIAL IS STRONG OVER 29/30 CELSIUS SST, ONLY THE VICINITY OF THE
COAST DURING THE FIRST 48 HOURS MAY LIMITATE THE RATE OF INTENSIFICATION.
Update #2 (19 January 2012 14:00): As of 14:00 on Thursday the 19th January, the storms in question have continued to intensify, the first to be named as expected in the previous update was 07S which is now Tropical Storm Ethel, while the closer to home 08S is has now become a tropical depression, namely Tropical Depression 8. This tropical depression is expected to become Tropical Storm Funso in the next day or two and is likely to meander around the Mozambique coast for a while before models have the storm heading inland in about a week. This system poses major flooding risks for Mozambique over the next few days and I am afraid we may see the potential for fatalities in that area if the storm behaves as forecast. The longer the storm meanders just off-shore the more rainfall that is likely to fall over eastern Mozambique. In the slightly longer range the models have what we assume will be Tropical Storm Funso moving SSW and the latest GFS run shows Funso dumping a bunch of rain on the already saturated Limpopo province in about 8 or 9 days. All those in Mozambique and Limpopo should keep a close eye on the system, though it’s too early to issue any warnings for S.A related to this system it does bear watching!
NEW UPDATES ARE TAKING PLACE ON THE FOLLOWING ARTICLE: http://www.stormchasing.co.za/articles-and-news/224-tropical-cyclone-funso