Friday and Saturday the pick of the forecast period

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 22nd 17th March)

Best Days: Fri: combo of south swells and mainly light winds. Chance for a late Thurs session when the wind backs off just before dark, and the swell starts to kick. Sat/Sun: light winds and a fun, slowly easing SE swell with mainly light winds. 

Recap: Winds held out from the N/NE on Tuesday though there were isolated pockets of light variable winds, with peaky waves in and around the 2-3ft mark. The gloomy weather of the last week finally cleared this morning, allowing surface conditions to sparkle a little more but the NE swell had eased further to 2ft and it’s dropped back to 1-2ft throughout the day. Conditions are very good though with light winds, though a fresh S’ly change is extending along the Far South and South Coasts as we speak.

This week (Mar 23rd - 24th)

The approaching southerly change will push across the Sydney region overnight, and although it’s expected to ease through Thursday we’ll still see a fresh breeze lingering across the coast in the morning. This will bump up surface conditions at south facing beaches, though by early to mid afternoon we should see an appreciable decrease in speeds and thus a late improvement in wave quality.

A new Tasman Low is developing at the moment (also responsible for the southerly change), and it will generate a fresh S/SE swell that’s expected to build throughout the day, along with the late arrival of a new long period S’ly swell generated by a sneaky polar low off the ice shelf, well south of South Australia on Monday.

This is a very unusual part of our swell window, and frequently goes unnoticed, usually because of - as will be the case this Thursday and Friday - a concurrent, similarly-sized but otherwise unrelated swell event from the same quadrant. 

The short range S/SE swell is expected to build slowly through Thursday toward a peak on Friday, with sets around the 3-4ft mark - the models actually have a late Thursday peak in size (only just) but I think it’s not resolving the short period energy very well and Friday will probably deliver the best waves from the Tasman Low.     

The long range S’ly swell will be much less consistent - up to fifteen or twenty minutes between waves - but will also likely plateau in size throughout Friday. Therefore, it’s possible that Thursday may take some time to get moving, especially as we’ll be starting from a small base with less than ideal conditions at first.

So, Friday is certainly the pick of the next two days, with Thursday’s abating wind regime likely to play out as an early light SW flow on Friday morning tending light to moderate S’ly throughout the day. It may be enough to ruffle the surface at exposed beaches but otherwise won’t cause too many problems. Just remember that beaches with less southerly exposure will see significantly smaller surf, being a combination of minor trade swell and refracted southerly energy.

This weekend (Mar 25th - 26th)

The Tasman Low will remain within a good part of our swell window on Friday but then weaken into the afternoon, and rotate clockwise outside of our swell window. This will lead to a slow decrease in SE swell over the weekend.

The models are suggesting 3ft surf on Saturday morning but I think there’s a good chance for some well exposed south facing beaches - especially across the Hunter - to see larger 3-4ft waves at times, before surf size eases into the afternoon, and further to 1-2ft by Sunday afternoon

No major wind strength is expected this weekend. After beginning with light offshore winds on Saturday morning, we’ll see a freshening NE breeze into the afternoon as a weak trough sets up along the coast.

The models have winds from every quadrant on Sunday (NNE at 12am, WSW 6am, S 12pm, E/SE 6pm) but this is a reflection of the weak pressure gradient under a minor troughy pattern. So, light and variable is the most likely outcome on Sunday. 

As such, aim for Saturday, preferably the morning, and you’ll do pretty well.

Next week (Mar 27th onwards)

Freshening NE winds on Monday will precede a gusty S’ly change Tuesday but at this stage no major surf is expected from either source.

The Tasman Low's track over the weekend pushes it near New Zealand and the models are suggesting a small but tight E'ly fetch along its southern flank could generate some small mid-period E'ly swell for Tuesday afternoon and Wednesday in the 2-3ft range. It's quite some time away and these erratic model suggestions have a habit of disappearing from model run to model run, but I'll keep an eye on it in Monday's update. 

Otherwise, next week’s Southern Ocean storm track suggests a strong alignment away from our swell window, which means we’ll be relying on local flukey systems in the western Tasman Sea to generate short lived events. I’ll also be keeping an eye on a lingering tropical Qld system that looks to affect the central to northern coastal region for much of the week. It’s nowhere near our swell window but is sometimes an indicator as to the broadscale weather patterns and will therefore be useful at assessing the long term swell potential beyond next week. 


Chris Buykx's picture
Chris Buykx's picture
Chris Buykx Thursday, 23 Mar 2017 at 4:57pm

4 wave sets 2'-3' - 15 minutes apart at a south swell magnet mid morning today. Very different to short range short period swell. This was definitely the early arrival of long range south swell from off the ice shelf. The swell from the Tasman Low has now filled in hiding this distinct swell

thermalben's picture
thermalben's picture
thermalben Friday, 24 Mar 2017 at 7:55am

Thanks mate - that's great info. The buoys didn't picked up this swell at all yesterday (no surprises), only just arrived at Eden at midnight! And at 15 seconds that's the mid-range energy from the backside of the event. 

thermalben's picture
thermalben's picture
thermalben Friday, 24 Mar 2017 at 7:56am

BTW, I posted my comment below (with SI grab) but didn't see your comment at the time.. weird. Not sure why (would have commented then if I had seen it!). Maybe it was obscured because I was on my iPad.

Clam's picture
Clam's picture
Clam Thursday, 23 Mar 2017 at 5:03pm

Deadly report thanks Chris

thermalben's picture
thermalben's picture
thermalben Thursday, 23 Mar 2017 at 6:43pm

Plenty of new S/SE lines showing across the Sydney region; smaller at Shark Island due to the direction but the lines are nicely defined.