Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 24th August)

Best Days: Tues/Wed/Thurs: tricky forecast but most locations should see solid E/SE swell, but with the best conditions north from about southern Sydney on Tuesday, possibly extending further south into Wednesday then all remaining areas by Thursday. Thurs/Fri: S'ly groundswell in the mix. Later Sun/Mon: new S/SE thru' SE groundswell. 

Recap: Saturday saw an easing southerly swell in addition to a small NE swell, and early light NW winds which created clean conditions at most regions. Both swells eased during the day and further into Sunday, with today seeing tiny waves across the Southern NSW coast.

This week (Aug 25 - 28)

So, we’ve got an East Coast Low developing on our doorstep, and the next few days are certainly looking very complex in the surf department.

The slow moving nature of this system means that there should be an axis point on the coast where conditions are divided between onshore and terrible, and offshore and really good (with the good surf located north of this axis). However, its precise location is unclear and requires a reasonable margin of error: say, around 30-40km. 

The best model guidance suggests that this axis point will be across the southern Sydney region. So, locations south from about the Cronulla Shire or the Coal Coast - give or take - are looking at driving E/SE winds on Tuesday, torrential rain and all of the other hallmarks of an ECL event. But to the north - and again, with some flexibility in the precise location - winds are likely to be out of the western quadrant.

Some model guidance also suggests that this axis may slowly move south into Wednesday, which would mean the region of favourable winds should extend south to Wollongong by this time, or possibly even further south.

However, it needs to be pointed out that even with the short range outlook, there are considerable differences between the models as to the precise location of the ECL, and consequently the local winds. It's quite plausible that these estimates will shift around by tomorrow (in which case I'll update in the notes below). Therefore, keep your expectations low as it's hard to know exactly what will pan out across the region.

As for surf - we’re looking at a wide range in wave heights. Locations in the direct firing line of the easterly gales off the south flank of the ECL will see the most size, but conditions will be terrible (set waves should build all day Tuesday and peak early Wednesday morning in the 6-8ft+ range). This looks to be somewhere around the South Coast up into the Wollongong or maybe even southern Sydney region. 

North of here, wave heights will be a little smaller but still very solid, peaking around the same time with 6ft+ sets across the Sydney region, and marginally smaller surf up into the Hunter (Tuesday will start off much smaller in size). However these regions will obviously benefit from the much improved airstream.

From Wednesday afternoon onwards, the ECL will weaken so the surf will slowly ease in size through the rest of the week. Conditions remain clean every day with light to moderate offshore winds, becoming a little breeze into Friday as a new system approaches from the south. 

Also in the mix on Thursday will be a small long period southerly groundswell, generated by an intense polar low tracking south of the Tasman Sea today and tomorrow. No great size is expected but south facing beaches should see some inconsistent 3-4ft sets that’ll mix in nicely with the easing E/SE swell from the ECL. This southerly groundswell will also ease in size into Friday.

This weekend (Aug 29 - 30)

We’ve got a complex weekend surf outlook at this stage too. The remnants of this week’s ECL are expected to slowly drift south, merging with a weak upper system associated with a series of Southern Ocean fronts. This is expected to form a new low pressure system in the Southern Tasman Sea around Friday, displaying several centres - however it’s as yet unclear how much surf each of them will generate. 

Currently, the models are suggesting we’ll see the best surf from this pattern early next week (with a reasonably strong S/SE thru’ SE groundswell) but prior to this - over the weekend - we are likely to see some short range southerly energy from an associated front pushing along the South Coast.

Due to the complex nature of this system, and the fact that it’s still five days away, we really need a few more days to firm things up. But at this early stage it seems reasonable to suggest that there’ll be some small to moderate southerly swell around for part of the weekend at least.

Next week (Aug 31 onwards)

As suggested above, the complex system developing in the lower Tasman Sea around Friday should produce a good shot of S/SE thru’ SE swell early in the new week. Current estimates are for a couple of days of waves, with a peak around Monday in the 3-5ft range at south facing beaches - but I’ll have a better estimate on this over the coming days.