South Australia is gradually heating up but as it does so, thunderstorms will be forming in the northeast of the state and then further south from this weekend. The storms will be confined to the North East Pastoral up until this weekend but should develop in the Flinders, Mid North, Riverland in the following few days. Showers or storms may even form as far south as the Mt Lofty Ranges, Murraylands and Adelaide early next week. There is little need for rainfall given the substantial soaking only a fortnight ago. Karoonda, in the Murray Mallee, had its wettest February in 100 years with 94mm, and eight wettest summer on record with 122mm for the season. If anywhere could do with some rain it would be in the South East. Keith is only 120km south of Karoonda yet only gained less than one third of its summer average rainfall, only 17mm. This makes it their driest summer in 31 years and fifth driest summer in more than 100 years of records. During the next few days a high, centred south of the state will move east and a low pressure trough in the northeast will edge south. As a result, winds will turn from mild southerly to hotter northeasterly, drawing in a bit of humidity from eastern Australia into the trough. The trough will trigger storms in the northeast of the state from Friday, possibly as far south as Adelaide on Sunday night and Monday and in the southeast from Tuesday. Storms have potential to bring more than 30 millimetres of rain, most likely on the ranges north of Adelaide. Whilst most vineyards coped surprisingly well from the heavy rain a few weeks ago, they would rather do without some more, given the ground is still fairly damp. A cooler change mid-next week should flush the moisture from the south of the state with drier, gusty southerly winds.