Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 1st September)

Best Days: Sat: light winds and slowly easing S/SE tending SE swells. Sun: early window at exposed northern ends. Wed/Thurs: building S'ly swells, though very acute in direction so not favouring all beaches. 

Recap: Large southerly swells built through Thursday, initially windswell ahead of an afternoon peak in groundswell, with south facing beaches reaching a solid 6-8ft, bigger through the Hunter. Winds were however fresh and gusty from the S/SW, following an early period of W/SW winds. Lighter winds have settled in today; early W/SW with clean conditions ahead of a moderate afternoon S/SE breeze. Surf size has eased from early 4-6ft sets at south facing beaches (bigger in the Hunter though smaller elsewhere).

This weekend (Sep 2nd - 3rd)

The southern and western flank of the Tasman Low responsible for yesterday’s swell is still active, mid-way between New Zealand’s South Island and Tasmania. It is however in a much weakened state and will disappear through Saturday morning. 

As such we’re looking at a slow easing trend of S/SE tending SE swell all weekend. There are no new swell sources on the cards, save a minor N’ly windswell on Sunday afternoon as a local airstream strengthens.

Saturday is still therefore the pick of the forecast period. As per Wednesday’s notes, I still think the model is slightly undercalling the morning wave heights (3ft) with occasional 3-4ft sets possible about south facing beaches at dawn but it’ll ease to 2-3ft by the afternoon. Expect slightly bigger waves across the Hunter, but smaller surf at beaches not directly open to the south. Winds will be light and variable all day so expect reasonably clean, if ever so lumpy at times. 

Sunday will see smaller surf easing from 2ft+ at south facing beaches (bigger in the Hunter) but you’ll have to surf early as we’re likely too see N’ly winds of moderate to fresh strength by late morning. Dawn could see a window of NW winds but it won’t last long.  

Model guidance is suggesting winds could go NW late in the day but I’d be pretty cautious on that. As it is, the SE swell will be very small by this time; there may be some small weak wind waves from the north but it’s not worth working around.

Next week (Sep 4th onwards)

Monday looks very small and clean. I am doubtful we’ll see much, if any N’ly windswell - the fetch looks interesting in snapshots but it pushes too quickly to the east to have any meaningful impact. The SE swell will be all but gone by this time too. And, a strong front pushing through Bass Strait on Sunday will have a touch too much north in its orientation to favour swell production for the NSW coast. 

However, a much more vigorous front crossing the SE corner of the country overnight Monday and into Tuesday looks a little better positioned for our coast. It’s still a knife-edge fetch with the main flow exiting eastern Bass Strait expected to be very west, but we should see a building S’ly swell late Tuesday (more so South Coast than Sydney), reaching the Illawarra/Sydney/Hunter coasts overnight and into Wednesday, bolstered by its lengthy duration and a strong secondary front approaching from the south-west.

As such I’m expecting Tuesday to remain very small just about everywhere ahead of a possible late kick down south. There is certainly a chance that the weekend’s model update could tweak Tuesday’s fetch in our favour (and bring about some potential for a late increase in S’ly swell in Sydney). If I see anything of interest I’ll update in the comments below.

Otherwise, Wednesday is looking at another unusually acute, though stepladder progression of building south swells. Model guidance isn’t liking this system yet (but I am!) - I reckon we’ll see 2-3ft sets at south facing beaches early Wednesday (much bigger in the Hunter) building to 3-4ft during the day, and possibly up to 3-5ft on Thursday (again, much bigger in the Hunter). However the steep southerly direction will create much smaller wave heights at protected locations. 

Conditions will be generally clean though blustery with fresh W/SW thru’ SW winds for much of these three days. If anything, confidence is certainly tilted towards later Wed and Thurs for this swell to really kick into gear. 

Friday will probably see easing S’ly swells and offshore winds but next weekend’s on track for a very large S’ly groundswell thanks to a large polar low projecting through our southern swell window later next week. More on this in Monday’s update.