In addition another sub-tropical low is expected to form over the weekend, this time off the QLD coast before drifting off towards the east and reconsolidating near the North Island.
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Current ASCAT (satellite wind speed) pass shows a low in the Northern Tasman with SE gales proximate to the NSW Coast and a long, broad fetch of E’ly gales extending from the Tasman out to a position north of the North Island.
If anything that eastwards movement looks slower than modelled on Wed so large surf will persist at elevated levels for longer.
That will lead to elevated surf from the SE-E for most of next week with just a very slow, gradual tapering off as the fetch slowly weakens while remaining basically semi-stationary.
There’s broad model agreement now for a low to form off the sub-tropical coast and merge with a Coral Sea low pressure centre, deepening explosively through Sat and into Sun.
Inshore we’ll see those winds between 10-15 kts through the morning tending stronger N’ly through the day and generating small NE windswells for the MNC up to Yamba, not much further north of there.
During this time frame a retreating but broad and long trade fetch will be supplying some background E’ly pulses.
Unfortunately, compared to Fridays expectations the interplay between these two systems is weaker, with a more constrained fetch of lower windspeeds that drifts away quicker than modelled on Friday. That will result in smaller east quadrant swell this week, relative to Fridays expectations.
There’s still some model divergence later next week but for now we’ve got reasonable confidence a broad fetch will develop through the Northern Tasman as high pressure moves into the Tasman and supplies an anchor for the low.
We'll see plenty of surf surf from this system initially but there is broad model agreement we’ll see this low deepen and develop into a more powerful system mid/late next week as it drifts into a position north of the North Island. Best case scenario is a quality E’ly groundswell event from this system.