22 Jun Low Pressure System To Bring Increased Severe Weather Threat To South Australia
Low Pressure System To Bring Increased Severe Weather Threat To South Australia
South Australia is expected to experience a multi-day severe weather event as an intensifying low pressure system in the Bight makes landfall over South Eastern SA. This system is expected to bring widespread strong to damaging winds, heavy rainfall, some storms and hazardous surf conditions.
On Tuesday, a low pressure system is located over the Western Bight, South of Western Australia, with an extensive cold front spreading through the Western half of SA into South West NT and Northern WA areas. Over the next 48-60hrs (Tuesday, Wednesday, Thursday), this low is expected to rapidly intensify and eventually make landfall over South Eastern SA near Adelaide or just South of Adelaide including Kangaroo Island before eventually pushing into Victoria where the severe weather threat will continue. One of the complexities with this setup will be how expansive the damaging winds extend from the low as well as the peak gusts in the system, along with the intensity of rainfall associated with both the front sweeping across the State and from the direct influence of the low pressure system.
The low looks likely to peak on Wednesday near the SA West Coast / Eyre Peninsula before making landfall on Thursday over South East SA. Through Wednesday, strong winds are expected to increase over the SA West Coast, Eyre Peninsula and Kangaroo Island, with strong winds spreading over the South Eastern quarter of the State on Thursday as the low approaches, makes landfall and moves across the region. Damaging winds (>90km/h) are LIKELY over the West Coast, Eyre Peninsula and Mt Lofty Ranges with locally DESTRUCTIVE winds (>125km/h) possible over Coastal areas of the Lower Eyre Peninsula, Western Coast of Kangaroo Island and parts of the West Coast depending on A) how close the low moves to these Coastal areas without making landfall and B) if any storms wrap around the low and move onshore over these areas, bringing enhanced wind gusts with them. The overall spread of strong to damaging winds across the Southern half of the State will likely result in some power disruptions also as some branches may come down on lines and small trees downed (especially in the higher gusts over the Eyre Peninsula / West Coast & Mt Lofty Ranges).
In addition to the obvious wind threat, increased rainfall is expected over the Southern half of the State also with models in strong agreement that falls of 25-50mm are expected over the West Coast, Eyre Peninsula, Kangaroo Island and Coastal areas of South East SA along with locally higher falls possible over the Eyre Peninsula and Kangaroo Island. These falls in general won’t be too much of a threat, but if they were to occur with any thunderstorms then localised and short lived flash flooding is possible.
In the wake of the low, as it moves Eastwards into VIC, the fetch of the winds will likely result in hazardous surf conditions also with peak wave heights of 5-7m over the West Coast, Eyre Peninsula, Kangaroo Island and widespread peak wave heights of 4-5m over virtually the entire SA Coast – with the most widespread wave activity being on Friday into Saturday morning. These increased waves will also coincide with moderate to strong Southerly winds which will result in a noticeable drop in temperatures, along with the feels like temperature being considerably lower than the actual air temperature.