Sydney Hunter Illawarra Surf Forecast by Ben Matson (issued Mon 26th May)

Features of the Forecast (tl;dr)

• Small clean surf Tues
• Rapidly building S'ly swell Wed, large for the late session, generally clean with offshore winds
• Very large S'ly tending S/SE swell Thurs, but generally wind affected at all but the most sheltered spots
• Solid, clean, easing swell Fri and early Sat with light winds
• Solid long period S'ly swell late Sat, easing Sun and into Mon, clean with light winds
• Small surf for much of next week

Recap

An excellent weekend of waves with offshore winds and steady E/NE swells that eased from 3-5ft Saturday to 3-4ft Sunday and further to 3ft this morning. 

Next week (May 27 - 30)

We’ve got a really dynamic week of waves ahead.

To kick things off, Tuesday will see a further reduction in the E/NE swell from today, and clean conditions as freshening NW winds veer W’ly as a vigorous front approaches from the west. 

We may see some minor N’ly windswells along the coast (owing to a local pre-frontal fetch strengthening today) but this looks to be poorly aligned for most of the Hunter/Sydney/Illawarra coasts, and will probably only benefit the Far South Coast at best. It’s not worth worrying about.

The main front will cross the coast early morning, and a new low pressure system will then develop in the central/southern Tasman Sea during the day, strengthening overnight and stalling by Wednesday into a deep Tasman Low, a real beauty. 

We’ll see several different sources of swell from this system, most of which will overlap at some point so it’ll be hard to distinguish them all (and kinda pointless really, seeing how rapidly surf size will increase). But let’s take a look at a few of ‘em.

An initial burst of gale force W’ly winds exiting eastern Bass Strait on Tuesday morning will generate a small southerly swell that’ll glance some of the region’s more reliable south swell magnets, however I doubt it’ll provide much of an increase before the end of the day (maybe a few South Coast haunts if we're lucky). 

The first proper S/SW fetch off Tasmania’s East Coast will develop later in the afternoon, and extend north into NSW latitudes by the evening, creating a large increase in S’ly swell for Wednesday morning, overtaking the small southerly spread mentioned above. 

I have a feeling that the wave models are undercooking surf size estimates for the morning session (2-3ft south facing beaches at dawn); regardless we are looking at a step-ladder increase through the day and by the evening should be pushing 6-8ft at south swell magnets. Conditions should be clean if a little blustery with fresh W/SW tending SW winds. We can also expect a wide variation in wave heights from beach to beach, owing to the steep direction (southern ends will be significantly smaller).

By late Wednesday, the Tasman Low will concurrently reach maximum strength (see below), which, along with a nice frontal slingshot around the low (albeit off-axis to the NSW coast), will generate an even larger pulse of S/SE swell for Thursday morning, probably north of 10ft at south facing beaches though again with a wide variation in size across the coast.

Winds will swing more to a gusty S/SW through the day but a few locations (i.e. Northern Beaches) should see lighter early W/SW winds. Overall it'll be best suited to protected southern corners and regional points, and even a few novelty spots that efficiently focus these swells.

Friday looks to be the pick of the working week.

The Tasman Low will have cleared to the east, allowing weak high pressure to settle across the coast and light winds to create clean conditions. Surf size will rapidly abate though early morning should still be 5-6ft+ at south swell magnets, easing to 4-5ft through the day (again, much smaller elsewhere).

Also worth mentioning that an impressive E’ly fetch to the NE of New Zealand right now - essentially the same fetch that generated the weekend’s E/NE swell, which has since retreated east - is producing a nice round of secondary E/NE swell that’ll rebuild through the second half of the week.

Of course, you won’t be able to see it underneath the dominant S’ly swells.

This weekend (May 31 - Jun 1)

The Southern Ocean is very active at the moment, and we have a really nice long period south swell due to arrive on Saturday afternoon, generated by a broad, intense polar low passing underneath Tasmania on Thursday (see below).

Swell periods could be up into the 18+ second range when it arrives - mid-late afternoon in Sydney (earlier on the South Coast) though the morning will start out smaller with leftovers from this week’s event.

As for size, we’re looking at another wide variation in size from beach to beach but south swell magnets should be up around 5-6ft+ by the end of the day. Even better, weak high pressure will maintain light variable winds across the region. Don't be surprised if footage emerges from some of the coast's offshore bombies with occasional 8-10ft sets.

Of course, beaches not open to the south will be much smaller. But the main contrast with this swell (compared to the Wed/Thurs/Fri swell) is that set waves will be much less consistent, so conditions may be more deceptive. And swell direction will be more south - and with a longer period - so there'll be a wider variation in size from beach to beach.

Surf size will then slowly ease through Sunday (initially still very solid early morning) with similar conditions as per Saturday.

Either way it’s shaping up to be a fantastic weekend of waves for anywhere that enjoys solid long period south swells. 

Oh, and there’ll be a small undercurrent of fun E/NE swell in the mix too, from the South Pacific source mentioned above. 

Next week (Jun 2 onwards)

This looks much more quiet for next week, which may be very welcome after what’ll have been an extended run of strong pumping swells. There’s a small south swell due mid-late week but nothing worth getting too excited about right now.