Coupla decent south swells on the way

Ben Matson picture
Ben Matson (thermalben)

Sydney Hunter Illawarra Surf Forecast by Ben Matson (issued Friday 25th June)

Forecast Summary (tl;dr)

  • Small fun south swells at the swell magnets this weekend
  • Bigger S'ly swell building Monday (average winds), peaking Tuesday (slowly improving winds)
  • Better S/SE groundswell arriving later Wed, easing Thurs, light winds
  • Chance for a decent E/NE groundswell later next week/weekend 


Freshening northerly winds built a small NE windswell on Thursday, which has held into today offering clean 1-2ft sets under light to moderate W/NW winds. A small southerly swell is also in the mix. 

This weekend (June 26 - 27)

Having not looked at the models earlier in the week, I’m not 100% confident on the source of the two new south swells pegged for the weekend. However, surf observations throughout Victoria today are on par with expectations and despite the shadowed storm track (via Tasmania), reliable south swell magnets should pick up some fun waves in the 2-3ft range, a little bigger across the Hunter. 

These swells are usually very inconsistent, and anywhere not completely exposed to the south will be a lot smaller in size (southern ends will likely be near flat). Fortunately, light offshore winds both days will maintain clean conditions.

As for the overall trend, the first swell is due to push through the region this evening, and will show largest early Saturday morning ahead of a slow decrease throughout the day.

The second swell is due into Sydney a few hours before lunchtime Sunday, so early morning may start off a little undersized, ahead of a boost into the afternoon. Of course, locations south of Sydney will pick up the second new swell earlier so south swell magnets in this region may see a full day of fun waves. 

Sunday is also expected to pick up a small secondary mid-period south swell from W/SW gales exiting eastern Bass Strait on Saturday afternoon. This swell will probably come in at a similar size as the long period groundswell(s), however the combination of the two overlapping south swells may result in occasional bigger sets on Sunday than mentioned above. 

Next week (June 28 onwards)

First up - there’s a nice looking band of trades out near Fiji at the moment, but it’s aimed up into the Coral Sea and South Pacific, away from our region. So we’re not going to see any trade swell early next week. 

A strong frontal passage below Tasmania over the weekend will drive SW gales through our south swell window, and initially a coastal southerly change on Monday (though without any major strength). The swell direction will remain acutely south, resulting in a similarly wide range of wave heights from beach to beach but it should push a little higher than the weekend, maybe 3-4ft+ at south facing beaches and up to 4-6ft across the Hunter.

The peak of this swell is due later Monday and (more likely) Tuesday morning, so expect smaller surf early Monday ahead of the upwards trend. As it is, Tuesday looks to offer the better conditions through this period anyway as Monday’s freshening SW tending S’ly winds will have given way to light variable tending E/SE winds as a ridge pushes north of the region. Easing size is then expected from Tuesday afternoon into Wednesday.

The parent polar low to this south swell will undergo reintensification south of New Zealand on Monday (see below), generating a brief new long period S/SE groundswell that’s due into the South Coast around lunchtime Wednesday, arriving late across the Sydney region and probably peaking overnight before easing through Thursday.

Hopefully we get a few hours of sunlight on this short lived event, as south facing beaches should see good 4-5ft sets (the models aren’t really picking it up very well) and winds look like they’ll be light under a weak pressure gradient. It’s worth pencilling in late Wed or early Thurs for this - right now, I like the look of this swell better than any of the preceding south swells.

Long term model runs are suggesting a deepening low pressure trough south of Fiji from about Tuesday onwards, that’s expected to remain slow moving for a few days. This has the potential for a significant E/NE groundswell later next week and into the weekend, though it’s still early days (and small changes in the position of this low will dramatically affect the swell outlook).

As I haven’t been watching the last few model runs, I’m not sure whether the current guidance is an outlier or if the trend is baked in - so let’s see how it pans out over the next few days.

Have a great weekend!


Ralph's picture
Ralph's picture
Ralph Saturday, 26 Jun 2021 at 9:11am

There was a bit of a pulse around late mid morning Friday down the south coast could that have been the first long period swell arriving early?

thermalben's picture
thermalben's picture
thermalben Saturday, 26 Jun 2021 at 9:16am

That was another south swell (separate to what's expected this weekend).

Stu2d2's picture
Stu2d2's picture
Stu2d2 Sunday, 27 Jun 2021 at 8:43am

Why the preference for the SSE groundswell over the SSW ones?

thermalben's picture
thermalben's picture
thermalben Sunday, 27 Jun 2021 at 8:48am

They get into more locations. Not just regionally, but more broadly across the state too.

Also tend to be a little more forgiving across some coasts, with a better response across some beaches that otherwise just close out on straight S or S/SW swells. 

Stu2d2's picture
Stu2d2's picture
Stu2d2 Sunday, 27 Jun 2021 at 9:30am

Not where I reside. But figured that was your reasoning.

joesydney's picture
joesydney's picture
joesydney Sunday, 27 Jun 2021 at 1:36pm

Why do S/SW swells close out beachies? I hate watching groomed offshore ruler straight swells close out. You would think more angle would mean less close outs?

thermalben's picture
thermalben's picture
thermalben Sunday, 27 Jun 2021 at 2:09pm

Ah, look it's just a general biased observation from ten years living on the Northern Beaches. South swells weren't deemed in a favourable light here (unless the banks were primo), however there are other coasts that love nothing more than to bask under the warm glow of a clean south swell.

Same goes for NE swells. They're awesome for almost everywhere! Unless you like in Cronulla etc.

gunther's picture
gunther's picture
gunther Sunday, 27 Jun 2021 at 5:47pm

Because they are usually long lines of groundswell - long period swells feel the sea floor a long way out and bend in making them seem more straight on than the buoy suggests.

sean killen's picture
sean killen's picture
sean killen Monday, 28 Jun 2021 at 5:08pm

My local needs a bit of east.. south swell over 4 ft+ is 200-300m close outs..when the banks are good maybe score .. pretty rare .. travelling required..