Some areas have already seen 2 months worth of rainfall overnight into Friday morning and these same areas are still sitting under heavy rainfall and severe thunderstorm activity. Rainfall is now leading to flooding in some locations and this is expected to become more widespread as we go through the weekend.
High humidity, deep atmospheric instability and a slack pressure pattern means the same areas are expected to be hit by torrential rainfall, leading to a 1/50 year event for some.
So lets take a look at the latest forecast.
Rainfall Next 10 Days
Extensive heavy rainfall continues to fall over the central and northern interior with some areas recording record rainfall for January tonight and again over the weekend. The coverage of rainfall will begin to reduce as we approach early next week, but may ramp up again around Australia Day with a low pressure system that forms on the trough and then kicks eastwards. This may spread a large slow moving band of thundery heavy rainfall over the entire state before clearing out by the end of next week with a cooler flow. So between now and the end of next week, there is the chance of rainfall most days throughout the state, the most widespread over central and northern areas through this period. The eastern Ag areas may stay mostly dry until next week. It depends on how the trough behaves in coming days which is changing from run to run. Some of this rainfall has already fallen.
Thunderstorm Forecast Saturday
Thunderstorms will continue from Friday into Saturday over the West Coast, through the Eyre Peninsula with some areas expected to see significant severe weather with thunderstorms. The risk will extend northern over northern areas of the state with heavy rainfall and damaging winds the main concern. The risk may edge very slowly towards the east.
Thunderstorm Forecast Sunday
Thunderstorms will continue to move eastwards into Sunday. The heavy rainfall may lead to flash flooding over the Agricultural areas and it may extend into the Adelaide region, but most likely sitting west of the region. The heavy rainfall will extend through northern areas again. With the trough broadening, there may be thunderstorms through the afternoon and evening over the northwest and western areas once again.
Flash Flood Risk Saturday
A very high risk continues over the West Coast and Eyre Peninsula through to the Northwest Pastoral Areas and towards the NT border. Significant flooding along the Stuart Highway is expected in parts between Port Augusta and Woomera. The risk may creep a little further east through the afternoon.
Flash Flood Risk Sunday
A very high risk continues over the Eyre Peninsula and extends east to the Mid North, Flinders and possibly Yorke Peninsula. Thunderstorms will also develop about eastern areas during the afternoon and evening with the trough broadening.
Riverine Flood Risk Friday through Tuesday
Significant rainfall of 100mm has fallen in scattered pockets so far and this will continue for a number of days and flooding is beginning to occur in some areas with ongoing heavy rainfall.
There will be more in the evening national update on the latest data sets as they start to come in during the next hour or so.