We have a deep low (985hPa) adjacent to Tasmania and another attached low centre further E in the Tasman with the long E/NE infeed into this complex low gyre focussed near the west coast of the North Island and slowly sliding out of the swell window.

This anchored trough fetch, or trough block pattern is favourable for swell production for almost the entire Eastern Seaboard and will come with mostly offshore winds until the weekend brings a more S’ly biased flow to temperate NSW. We’ll see remnants of a small low at the terminus of the trough get captured over the weekend and generate S swells from the return flow of a regenerated low.

The “trough block” pattern mentioned on Wed looks to set-up as the clearing trough Mon sets up a long N-S oriented line in the Tasman to Coral Seas and focusses a long E’ly fetch through this vast area. Windspeeds are the limiting factor but we should see a steady increase in E'ly swell from Thurs into next weekend.

A trough in the Coral Sea accentuates an unstable SE flow in the sub-tropics and adds a local source of SE-E/SE swell into the mix north of Coffs. The high will be dominant right through into next week, as it slowly drifts into the Tasman, with some possibly juicy long range scenarios.