Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 29th May)

Best Days: Plenty of south swell most days (initially small early Thurs), but windy at times out of the south late Fri, Sat, late Mon and Tues. Sunday the pick with light winds and strong though easing S'ly swell. 

Recap: Tuesday delivered great waves at beaches that enjoy southerly swells, with Sydney’s south facing beaches seeing solid 3-4ft sets, and the Hunter pushing up to 4-5ft at times. However, wave heights were smaller south from the Illawarra due to the alignment of the source; a SW fetch extending north-east from Southern NSW. Conditions were clean with offshore winds. The swell eased rapidly overnight as expected, leaving us with 1-1.5ft waves early this morning, and near-flat conditions this afternoon, under brisk offshore winds.

Newcastle on Tuesday, and Wednesday. Perfect 4-5ft one day, 1ft the next.

This week (May 30 - 31)

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There’s a lot of activity in our south swell window. And it’s all associated with an amplifying node of the Long Wave Trough, that’s also bringing about an impressive cold snap to the region. 

Tuesday’s swell was the result of the first phase of the LWT, but it’s still actually positioned over Tasmanian longitudes, which means S/SW gales on its western flank - required to generate south swell for us - are inside Tasmania’s swell shadow.

However, the LWT will move into Tasman Sea longitudes overnight, and strong S/SW winds will develop parallel to the South Coast early Thursday, building S’ly swells across our region. A strong polar front will race up behind (overnight Thursday), merging with the pre-existing S’ly flow and generating even bigger S’ly swells for Friday and Saturday.

There’s one other southerly swell source on the boil. A deep polar low well to the SE of Tasmania (see chart below) has 40-50kt S’ly winds around its core, and although there’s a large travel distance (the low won’t move north through our swell window, but remain at polar latitudes), the stronger winds will be responsible for larger swell periods in the 17-18 second range.

It’s hard to discern when this energy will arrive (as the models are having difficulty splitting up the swell trains - so they’re throwing them in all together), but late Friday or early Saturday looks likely. Though, it’ll be hard to pick from beneath the short and mid-range noise.

And lastly, W’ly gales exiting eastern Bass Strait today will kick up a small spread of S’ly swell for Thursday morning, exclusive to south swell magnets, mainly north from Sydney.

Local winds will remain W/SW for most of Thursday and early Friday, but we are looking at strong southerlies developing after lunch on Friday as last front in this sequence impacts the coast as the LWT continues to move further east into the Tasman Sea. 

As for size, expect small, slow S’ly swell early Thursday (2ft south facing beaches, tiny elsewhere but up to 3ft in the Hunter), building steadily during the day, reaching 3-4ft at south facing beaches by late afternoon (same regional size caveats as per usual). 

On Friday, I think our models have the surf size about right - building from 3-5ft to 6ft+ at south facing beaches between dawn and dusk, bigger in the Hunter but a lot smaller at locations with less southerly exposure. Of course, the afternoon size peak will be accompanied with the southerly wind shift, so expect protected southern corners to have the best waves. 

This weekend (June 1 - 2)

No change to the weekend forecast. 

Friday’s late peak in size should hold through Saturday morning, anywhere between 6ft to maybe 8ft at south facing beaches (a little bigger in the Hunter, much smaller elsewhere), but easing slowly throughout the day.

Local winds will be moderate to fresh southerly in the lee of the LWT, but there is a reasonable chance for isolated pockets of early W/SW winds (i.e. Northern Beaches). So, conditions won't be great but there'll be plenty of options across sheltered spots given the size of the south swell.

Sunday looks much better on the surface with light variable winds under 10kts all day (mainly offshore), and slowly easing S’ly swells from 4-6ft to 3-4ft at south facing beaches, smaller elsewhere but bigger across the Hunter. Well worth your time and effort.

Next week (June 3 onwards)

Two systems are expected to merge as one large Tasman Low early next week: an initial polar front well south of Tasmania on Saturday, and mid-latitude front crossing the Tasmanian region around Sunday. 

At this stage Monday will see small leftover S’ly swells and freshening W’ly winds as the low develops; there’s a risk of a gusty S’ly change (and associated rapid swell increase) during the afternoon but for now Tuesday morning’s on track for a large, windy southerly swell combo in the 6-8ft range.

Further systems trailing behind look like they’ll maintain vigorous southerly swell activity through the rest of the week too.

More on that in Friday’s update.