The current high cell in the Tasman has a trough of low pressure perched atop it, maintaining an E’ly fetch at a southerly latitude- roughly due East of Sydney.
The next high pressure system moves into the lower Tasman Mon, at a very southerly latitude, even by La Niña standards.
The squeeze between a 1001 hPa low off the South Coast and 1030 hPa high moving through the Eastern Bight is producing a line of gales off the NSW South Coast, extending northwards up to the Hunter and southwards into the Tasman Sea.
This fetch provides a pulse of S to S/SE swell before another low forms in the trough line off the NSW Central Coast Tues, rapidly re-invigorating a robust S to S/SE fetch off the South to Central Coast before slowly drifting off to the SE later this week.
That marks the emergence of another major system, as the remnants of the trough/low get re-energised by another upper disturbance being pushed Eastwards by a high in he bight. More on this later it’ll generate hepas of swell next week once it spins up.
This is maintaining a deep E’ly flow, with coastal troughs and a surface low off the NSW North Coast, now moving South.
Lots of action next week. We’ve got a stack of strong E to E/NE swell incoming- with some model variability suggesting we’ll need some further fine tuning next week.
This will be generated by the increasing E to E/NE winds in the deep E’ly wind field retrograding S and W towards NSW as a large area of tropical low pressure off the QLD coast starts to deepen and move S.
The latter part of the week will see a NE flow develop, with periods of light NW breezes inshore. Trade flows across the South Coral and Northern Tasman Sea won’t be particularly strong this week but the broad scale coverage of winds will be enough to see a modest building trend into Thurs and Fri.
The southerly change pushing up Southern NSW this afternoon doesn’t have a lot of strength nor longevity in its fetch, but we do have some swell potential for the weekend.