Multiple swells from the southern quadrant

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 7th September)

Best Days: Tues: fun small S/SE swell (and a poss late S'ly pulse) and offshore winds. Wed: building combo of strong S and S/SE swells with early offshores. Thurs: easing combo of S and S/SE swells, with OK winds early. Fri: better winds, easing S'ly swells. 

Recap: The weekend delivered fun surf, with a mix of S’ly and SE swells providing 3ft waves at most beaches Saturday, easing a little on Sunday (bigger sets reported in the Hunter). Winds were light offshore Saturday morning ahead a moderate southerly change, and although an onshore airstream occupied most of Sunday, wind strengths remained light so conditions were reasonably good (better than expected, anyway). Today we’ve seen a new S/SE swell push through with very inconsistent set waves pushing 3ft across most regions, however it seems to be a smidge under general size expectations with the Hunter not (yet) picking up bigger waves. Winds were NW early but are now N’ly tending NE. A SW change is expected later.

This week (Sep 8 - 11)

No major changes to the forecast for this week, as per Friday’s notes.

We’re at the start of an extended run of S/SE swell originating from a strong frontal progression south of New Zealand from late last week through the weekend, which is expected to reach a peak on Wednesday. With today’s size coming slightly under expectations, I’ve pulled back wave heights from this source for the next two days as they’re all very similar in origin. Therefore, let’s aim for most open south facing beaches to hold somewhere in the 2-3ft range on Tuesday, with a few bigger waves in the Hunter. Conditions should be clean with offshore winds from the W, tending SW later, thanks to a develop low east of Tasmania.

On Wednesday, the S/SE groundswell will bump up a notch thanks to a peak in intensification in the core fetch yesterday, with most open south facing beaches likely to push up towards 3-4ft by the afternoon (this swell is expected to hold through into Thursday). However, we will see a secondary south swell that’ll end up being the dominant swell train by the afternoon, originating from the low developing east of Tasmania Tuesday. It’s expected to track N/NE parallel to the southern NSW coast and will kick up wave heights to 4-6ft throughout the day (maybe not peaking until the afternoon). The upper end of this size range is more likely in the Hunter, with most of Sydney's south facing beaches likely to peak in the 4-5ft range.

In fact, we may also see a small spike of fresh S’ly swell very late Tuesday from the early incarnations of the developing low - a gale force W/SW airstream exiting eastern Bass Strait from this evening onwards. But this swell probably would just slide under the pre-existing S/SE groundswell (it’ll be most noticeable by an uptick in the consistency of set waves, as the pre-existing S/SE swell is likely to be very infrequent).

Wednesday’s conditions will however be under the influence of a gusty SW tending S/SW airstream (may be W/SW for a period early morning at some locations). So, you’ll have to surf early for the best conditions as exposed spots will become blown out by the late afternoon. However there should be enough size for small waves inside sheltered southern corners. Just keep in mind that wave heights will probably be a little undersized early morning, at the same time we're expecting the best conditions. 

On Thursday, conditions are looking to be similar to Wednesday although with slightly less wind strength. Both the S’ly and S/SE swells will be slowly easing by this time however the early morning should still be quite strong with south facing beaches somewhere between 4ft and maybe 6ft (smaller at beaches not open to the south; the upper end of this size range across the Hunter). A few locations should see early W/SW winds but it’ll veer SW and then S/SW throughout the day. 

At this stage Friday looks like it’ll finish the working week with light variable winds and further easing S’ly and S/SE swell, around 3ft at south facing beaches (bigger in the Hunter) and smaller surf elsewhere. So, still plenty of leftover options but certainly nowhere near as much size as mid-week. 

This weekend (Sep 12 - 13)

Nothing major expected for the weekend at the stage but there’ll be waves. A series of strong but poorly-aligned fronts in the Southern Ocean (well below the Tasman Sea) on Wednesday and Thursday look like they’ll generate some small useful southerly swell for south facing beaches. Most Sydney locations will probably remain small (2ft+) both days but the Hunter often does well from these patterns and should therefore see bigger waves. 

Conditions are looking a little mixed though with winds expected to freshen from the northern quadrant right across the weekend. The good news is that this may also whip up a small local NE windswell but it’s certainly got the potential to spoil conditions away from northern corners. Period of NW winds are possible in the mornings. 

I’ll also be keeping my eye in further model runs on the leading front from this progression near New Zealand, which is currently (on Friday) expected to intensify as it tracks along NZ’s West Coast. We may see model updates pinch this off as a small low which would then increase the potential for a SE swell sometime Sunday or Monday. It's only a low chance right now but I thought I’d flag the possibility early.

Next week (Sep 14 onwards)

Nothing major for next week at this stage, only the remote chance for that system off NZ’s west coast Friday to generate some SE swell for early next week. Other than that there are no major systems on the long term radar. Let’s see how things are looking Wednesday. 


ACB__'s picture
ACB__'s picture
ACB__ Monday, 7 Sep 2015 at 3:17pm

Hey Ben,

Hope you're enjoying the new residence!

When you're writing these notes, for the hunter region on a south swell you say as a rule of thumb to add a foot or two to the forecast as it usually picks it up more than Sydney.

What would be your rule of thumb for the gong & deep south, EG, Ulladulla & Batemans.

evosurfer's picture
evosurfer's picture
evosurfer Monday, 7 Sep 2015 at 4:16pm

From my experience if the swell is real south the gong is smaller than say Cronulla.
South from there or really Nowra I think maybe a little bigger.

Craig's picture
Craig's picture
Craig Monday, 7 Sep 2015 at 4:26pm

Yeah depends on the swells origin.

If being generated off the Southern NSW coast, then smaller the further south you go.

If from a polar front below Tassie or at entrance to the Tasman Sea, usually even spread, if not sometimes bigger south from Nowra.

blindboy's picture
blindboy's picture
blindboy Monday, 7 Sep 2015 at 5:49pm

Shellharbour to Shoalhaven Heads often seems to miss out on south swells.

geoffrey's picture
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geoffrey Tuesday, 8 Sep 2015 at 7:24pm

and wollongong always misses out on south swells

thermalben's picture
thermalben's picture
thermalben Tuesday, 8 Sep 2015 at 6:48am

Seems very slow going this morning but there are occasionally some nice waves at south facing beaches. Here's a few random frames captured by our Bondi surfcam.

thermalben's picture
thermalben's picture
thermalben Tuesday, 8 Sep 2015 at 4:20pm

Plenty of strong lines in Bondi this arvo, looks to be pushing head high to slightly overhead on the bombs.

thermalben's picture
thermalben's picture
thermalben Tuesday, 8 Sep 2015 at 4:35pm

Getting bigger now, the second one in this sequence has gotta be a solid 4ft+.

Craig's picture
Craig's picture
Craig Tuesday, 8 Sep 2015 at 5:01pm


thermalben's picture
thermalben's picture
thermalben Wednesday, 9 Sep 2015 at 7:51am

This ain't a small set.