Right on cue, as head into the first week of winter, a nice cold outbreak and blast of W’ly winds with accompanying S’ly swells affects the entire East Coast.
Attention will still be focused on the tropics/sub-tropics as a surface low forms at the northern end of the trough off the CQ coast through Thurs/Fri and tracks southwards into the weekend, bringing (another!) rebuild in E’ly swell.
Sub-tropical troughs and the remnants of TC Gina near New Caledonia are maintaining a deep E’ly flow through the Coral Sea while the last in a series of powerful cold fronts are now sweeping up past the South Island of New Zealand with small S to SSE swell pulses to come over the next couple of days from this source.
The Coral Sea has become inflamed with SE-ESE Tradewinds, enhanced by a trough off the CQ Coast and a developing low near New Caledonia. Through the weekend, short range ESE swell from the tradewind fetch will supply the dominant swell trains, especially in SEQLD.
We’re going to see multiple overlapping pulses of S swell over the coming days as fronts slingshot around the parent low on an active sea state, with the biggest surf coming with some dodgy winds as the high pressure ridge sets up. Following that an active tradewind pattern in the Coral Sea supplies another round of E swell.
Stronger fronts push up into the Tasman from later Wed, bringing a S'ly flow and bigger S swell as we head to the end of the week.
The fetch of deep E to E/NE winds in the Coral and Northern Tasman Sea is contracting northwards around a surface low off the CQ/Fraser coast, and expected to fizzle out over the weekend. At present gales are retrograding towards the QLD, generating large swells.
A long interior trough and developing trough/low off the North QLD coast are tightening the pressure gradient along most of the ridge, bringing fresh onshore winds and a deep E’ly pattern to the majority of Tasman Sea and Central/Southern Coral Sea.
Further north an interior upper trough and potential coastal trough/surface low will combine to drive an intense E/NE to NE wind flow through the Coral and Northern Tasman Sea, generating a large stormsurf by Fri.
GFS has the more bullish outlook, with a trough or potential surface low forming off the Fraser Coast and tracking south through Fri13th- energising a long E to NE fetch through the Central Tasman to Coral Sea. In effect, it’s a slightly less energised version of the June 2016 Black Nor-Easter set-up.