Forecast issued at 4:32 pm CDT on Wednesday 18 January 2017.
A near stationary trough of low pressure lies across the Flinders district and south of the pastoral districts and a high pressure system well south of the Bight will move steadily eastwards today. A broad area of low pressure will move over the State on Thursday then another high pressure system will develop over the Bight later on Friday. This high will move southeastwards on Saturday to be centred over the Tasman Sea on Sunday.
Forecast for the rest of Wednesday
Humid with a high chance of showers and isolated thunderstorms over the Pastoral and Flinders districts and near the north of Spencer Gulf, with thunderstorms increasing to scattered about the ranges north of Hawker. Mild to warm in the south grading to hot to very hot in the north. Moderate southeasterly winds, fresh about the coasts and ranges, tending light to moderate northerly in the far north.
Thursday 19 January
Humid. A medium chance of rain south of about Port Lincoln to Lameroo during the morning. A high to very high chance of showers and thunderstorms developing, mainly during the afternoon and evening, becoming areas of rain about central and eastern districts in the evening. Local heavy falls with thunderstorms. Warm in the southeast grading to hot to very hot elsewhere. Mainly moderate northeast to northwesterly winds in the north and southwest to southeasterly in the west and south.
Friday 20 January
A high to very high chance of showers about the northern pastoral districts. A moderate to high chance of showers over the remainder of the pastoral districts and the agricultural area east of a line Whyalla to Cape Jervis, contracting to the pastoral districts by afternoon. A slight chance of showers about remaining parts, most likely near the coast. Thunderstorms possible about the pastoral and Flinders districts, and about the Mid North and Riverland districts in the morning. Mild to warm in the south and west grading to very hot in the northeast. Moderate to fresh southeast to southwesterly winds extending throughout.
Saturday 21 January
A slight chance of showers northwest of a line Ceduna to Leigh Creek, increasing to a medium to high chance of showers with isolated thunderstorms northwest of a line Coober Pedy to Moomba. Warm in the south and west grading to hot to very hot in the north. Light to moderate southeast to northeasterly winds.
Sunday 22 January
A slight to medium chance of showers northwest of a line Port Lincoln to Roxby Downs to Moomba, increasing to a medium to high chance of showers in the far west. Isolated thunderstorms possible north and west of Coober Pedy. Hot in the south and west grading to very hot in the northeast. Light to moderate southeast to northeast winds. Cumulative rainfall totals until midnight Sunday are expected to be generally 10 to 30 mm, decreasing to 5 to 20 mm in the northeast. Local falls of 30 to 60 mm with thunderstorms.
Monday until Wednesday
A slight to medium chance of showers over central and western parts extending east during Tuesday then contracting to the far north and the coastal fringe on Wednesday. Hot to very hot with freshening northerly winds ahead of a milder, fresh southerly change.
The next routine forecast will be issued at 5:30 am CDT Thursday.