Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 18th August)

Best Days: Tues/Wed: solid but windy surf. Thurs: improving conditions with easing size. Fri/Sat/Sun: fun waves at open beachies with light winds. 

Recap: A strong, long period southerly groundswell occupied the region on Saturday, easing into Sunday morning. A new E/NE swell built throughout Sunday but kicked in strong late afternoon with excellent conditions and epic waves reported in most areas north of the Coal Coast. Sunday’s swell held into this morning but conditions deteriorated as strong southerly winds enveloped the coast from pre-dawn (south of Sydney), then up into the Sydney region (early-mid morning) then the Hunter (early/mid afternoon). These winds are now also building a solid local southerly swell, in addition to a large SE groundswell originating from the southern flank of the low.

This week (Aug 19-22)

Gotta love an East Coast Low - the persistent dry, sunny weather over the last few months has been getting me down (joking!).

What was a complex trough of low pressure over the western Tasman during the weekend deepened significantly on Sunday, forming a series of small low pressure centres that are delivering a welcome round of rain, wind and large surf to the coast. The good news is that there won’t be any shortage of surf this week. The bad news is that it’s going to be tricky working around the local winds as these small low pressure centres move in and around the broad Tasman trough.

Swell wise, there’ll still be some leftover E/NE swell in the mix on Tuesday but for the most part it’ll be a combination of easing S’ly windswell and strong, but moderate SE groundswell.

However a secondary front is expected to push up the coast early morning, and this’ll kick up a strong new short range south swell that’s expected to peak in size during the day - albeit with rather poor surface conditions at most breaks as galeforce southerlies dominate the region.

Tuesday may however offer a short window of opportunity north of Sydney early morning - possibly just confined to the Northern Beaches - with a temporary outflow from the W/SW as the southerly change approaches (I’m not expecting to see this brief window south of Sydney at all, even the Hunter may succumb to the southerly before the Northern Beaches).

Wave heights will be upwards all day and should reach 6-8ft at exposed south facing beaches by late afternoon (smaller in the morning). Expect smaller surf at beaches not completely open to the south however due to the lingering E/NE and SE swell trains there should be quite a bit more size than what’s expected under straight southerly swell regimes. So, southern corners should have some fun waves if you don't mind the blustery conditions.

Also, and despite the lack of favourable winds, we probably won’t see much of a dip in size on the South Coast due to the persistent fetch aimed into regions south of Wollongong overnight. So expect large windy waves all day down south.

As the low moves further east into Wednesday, we’re still likely to see a strong southerly gradient flow across the southern NSW coast through the middle of the week. Wave heights will slowly ease back and will start to be more dominant from the south (still be in the 6ft range at south facing beaches early) however conditions will really only be workable inside protected southern corners, where it’ll be much smaller. There is a chance for a brief sou’wester at dawn in a few selected spots (i.e. Northern Beaches) but I wouldn’t hold your breath for much leeway.

On Thursday we’ll start to see a more marked downwards trend from the southerly swell (early 3-4ft sets, smaller later), but also the arrival - sometime mid-morning - of a small new SE swell, generated by a secondary fetch developing over new New Zealand on Tuesday.

There won’t be much size in this (say, the odd 3ft set at open beaches), and although lingering S/SE winds are likely to maintain some surface bumpiness, wind speeds will throttle right back and we should see a gradual improvement during the day (I’ll refined these thoughts on Wednesday). Could be some nice peaky surf on offer in any case.

Friday looks like it’ll be back to generally light winds, clean conditions and the slow easing of the previous S’ly and E/SE swells. A fun end to the working week for the beach breaks, with hopefully a few new gutters and banks to boot.

This weekend (Aug 23-24)

The overall weekend trend looks small but fun with light winds as a weak ridge of high pressure settles to the south of the state, across Victorian longitudes and spreading out into the Tasman Sea. 

There’s a couple of areas of possible new swell, albeit without much size: a small southerly fetch off the SW tip of New Zealand’s South Island on Thursday may deliver some small refracted SE swell Saturday, and we may also see some small short range east swell from the top of the high throughout Sunday (as a broad but ultimately weak trough is expected to slowly push down from the southern Coral Sea, which may strengthen a minor east flow in our swell window). 

Either way, there should be some small peaky options at exposed beaches with good winds. I’ll take a closer look on Wednesday.

Longer term (Aug 25 onwards)

Nothing major on the synoptic charts beyond the weekend at this stage. The main area of interest is probably the Northern Tasman Sea which may see slow developments towards an (unseasonal) easterly regime, but it’s very early days yet - and in any case such a setup would favour the Northern NSW Coast and SE Qld rather than Southern NSW. Let’s take a closer look on Wednesday.