Issued 9th May 2018. South East South Australia including Adelaide will feel a Winter like cold blast on Thursday and Friday this week. Adelaide is heading for a chilly top of 16C on Thursday with an extra 5C less for wind chill factor. This system will bring an end to the above average Autumn temperatures experienced so far. Above image maximum temperatures via BSCH.
A deep low pressure system is moving North East across the Eastern Bight on Wednesday afternoon which is forecast to develop further in Bass Straight during Thursday. A very strong cold Southerly airmass will push across South East South Australia with wind gusts between 60 and 80km hr.
Showers and possible isolated inland storms are likely to develop on Thursday, both could contain small hail due to very cold upper level air. Rainfall totals are only expected to be 5 to 15mm at best unfortunately. Below image showing very strong Southerly winds in red and purple during Thursday via Windy.com
Minimum temperatures will drop to between 4 and 7C across inland parts of the South East though frosts are unlikely at this stage.
Very large swell of 4 to 6 meters is also expected to develop along the South East Coast from Kangaroo Island to the Victorian border. Wave heights of 2 to 2.7 meters are forecast in open waters of the Spencer Gulf and St Vincent Gulf. This large swell will begin to ease during Friday.