Good things happen when cold meets warm, and more so when cold air interacts with warmer, moister air.

Summer has only just begun but we're already seeing the Australian continent heating up, though over in Western Australia this will be broken during the weekend.

Formation: A strong polar front will project up towards the south-west of the state on Saturday, but it's the cold air in which this system holds that's of interest. The front will transport a deep pool of cold air from Antarctica to just off the the south-west tip of WA, resulting in the formation of a severe mid-latitude low. The air is so cold it will nearly (though likely fall just short of) delivering snow to the top off Bluff Knoll in the Stirling Ranges.

Impact for Indonesia and Western Australia: At the low's peak intensity a fetch of severe-gale to storm-force S'ly winds will be projected north towards Indonesia, generating a large directional S'ly groundswell for Java and South Sumatra later next week (likely to 6-8ft).

This low will also generate large but stormy waves across the West Australian coast, reaching the XL range Monday morning though with strong onshore south-west winds.

The low is forecast to start weakening while moving east through early next and as it does so it will start interacting with an inland surface trough sitting near the South Australian and West Australian border.

Impact for South Australia and Victoria: The surface trough will be drawing in moisture from the tropical north and as both start drifting south-east into the Bight we'll see them combining, resulting in the re-intensification of the low south-west of Victoria and west of Tasmania.

This will trigger multiple fetches of gale-force winds aimed through South Australia's, Victoria's and Tasmania's swell windows generating a decent groundswell event mid-late week.

Under this pattern local westerly winds are expected to favour the more protected coasts of Victor Harbor, the Surf Coast and the South Arm, with it being too early to put a number on the expected size.

Impact for South Pacific: Further more the strong polar low will generate swell for New Zealand Christmas weekend, and Fiji/Samoa Christmas Day/Boxing Day (and to a lesser degree the East Coast).

These systems are fascinating to watch unfold, with a series of events flowing on from one significant cold outbreak off the West Australian coast. Keep an eye on your local forecasts for more details on the coming swell events.