Tuesday will be the hottest day since summer for parts of South Australia, including Adelaide, with temperatures rising to the mid-to-high 30s.
The areas likely to experience their hottest day since summer include Adelaide and the Mount Lofty Ranges.
Northerly winds will draw heat from the interior of the country, making much of the state five to 10 degrees hotter than it was Monday and seven-to-12 degrees above average.
These hot northerly winds will also be quite dry and gusty, causing fire danger to increase in many areas.
On Monday, extreme heat and fire danger occurred in the far west of the state.
At Nullarbor 40-degree heat combined with wind gusts greater than 50km/h and humidity less than 10 percent to produce the extreme fire danger.
These hot northerlies will develop ahead of a low pressure trough, which will also cause a few thunderstorms. Storms will be mainly in the west of the state and some may produce damaging winds, most likely in the north.
As the trough moves east it will also cause hot northerly winds to turn cooler southerly, bringing an end to this brief hot spell.
After Adelaide reaches about 37 degrees a thunderstorm is possible, in the late afternoon or evening but any storm is unlikely to bring much rain. Any shower or storm will occur at about the time of a cooler wind change, which will help cause the temperature to drop to about 20 degrees later in the evening.
After a few cooler days, Adelaide and much of SA will heat up again on the weekend.
© Weatherzone 2012
14:24 EDT Thunderstorms are due to develop daily across New South Wales and Queensland for almost two weeks.