Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 27th June)

Forecast Summary (tl;dr)

• Windy new S'ly swell building Mon PM, easing Tues
• Small clean peripheral swells Wed/Thurs
• Onshore winds developing Fri as strong high and potential coastal low kick off
• Strong onshores this weekend with large storm surf likely to develop
• Size and conditions of large E/NE swell early next week dependent on position and strength of coastal low, stay tuned for updates

Recap

Not much surf to speak go over the weekend. Both days saw small clean surf, in the 1-2ft range Sat, marginally smaller Sun. Pleasant under sunny skies and offshore winds. A S’ly change has pushed through today, with early clean conditions now deteriorating across most of the region. Small leftovers are being replaced by a building short range S swell signal. 

We’ve got a dynamic week ahead, with potential for a major winter storm of tropical origins over the weekend. Read on for details.

Bit o' babyfood to start the week in the sheltered Bays

This week (June 27-July1)

A potentially explosive pattern was mentioned last Mon, for the period leading into the first weekend of July and models are now firming on a strong coast hugging low moving south from the Coral Sea during this time frame. That portends plenty of wind, swell and potentially severe weather. More on this in a moment. 

At present a robust but short-lived cold front is aggressively pushing north along the NSW Coast, with a high pressure ridge behind it, producing a quick sugar hit of S swell for the region. Relative calm then sets in behind it before the situation becomes incredibly dynamic by the close of the week.

In the short run and there’ll be plenty of S swell on the menu tomorrow but not many good options as fresh S’ly winds turn S/SE as the high pressure ridge sets up along the coast. There’ll be 3-4ft of mostly short-range S swell on offer, bigger 4-5ft on the Hunter, although size will ease up through the a’noon. An early clean window is possible on the Northern beaches, but most exposed breaks will have plenty of wind wonk through it, so sheltered spots will be the go, and they will be considerably smaller. 

High pressure moves over Central/Coastal NSW on Wed, bring light winds and settled conditions. Surf will have eased back quickly with just a small leftover signal of S swell, around 2-3ft at exposed S facing breaks, easing during the day. Light morning land breezes will tend variable to NW during the day so it’s worth checking out local S swell magnets.

Another cold front pushes through the Tasman on Thurs, bringing another S’ly change, likely mid-late morning. Compared to model runs on Fri this frontal system is weaker and more mobile and less of a swell producer. Thurs will be small with minor mixed bag of leftover S swell in the 2ft range.

Friday is where things get very dynamic. There will be some S swell in the water from Thursdays front but conditions are looking very iffy at this stage.  A monster high moving well south of the Bight is expected to rapidly set up a strong ridge along the NSW Coast. Cradled by this ridge will be a very complex series of low pressure troughs, including an interior trough and a broad trough in the Coral Sea, with a potential surface low forming off the QLD or NSW Coast. 

Models are still divergent on where the surface low forms so we will need to revise as we go on this dynamic event, likely day by day.

EC model forms a surface low off the SEQLD/Fraser coast drifting it slowly S to hover off the NENSW coast over the weekend and early next week.  That will put the focus of huge seas and severe weather off the Mid North Coast to QLD border region over the weekend and early next week.

GFS model suggests a more southward located coast-hugging low with gales adjacent to the coast from the lower Mid North Coast down to South of Sydney. That will see huge surf develop later in the weekend and staying large into early next week with clearing offshore winds possibly as early as Mon. 

Back to Friday and we’ll see precursor strong onshore winds develop through the day, likely wiping out surf prospects for the vast majority of the region.

This weekend (July 2-3)

As noted above, we will be under the influence of a major weather event this weekend. 

Strong onshore winds are likely Sat with mostly short range E/SE swell building into the 4-6ft range but with extremely low quality.

Sunday is potentially huge (>10ft) and onshore with gale force E’lies although there is low confidence in the call due to model divergence (see above). Onshore winds are almost certain Sunday so expect surf of low quality. Stay tuned for updates Wed. 

Next week (July 4 onwards)

Everything depends on the position, strength and movement of the coastal low early next week. There’s a range of outcomes on offer, and most of them involve large surf from the E-E/NE.

Onshore winds and large surf could possibly extend into Wed under the EC scenario.

Or we could see an offshore flow develop as early as Mon next week, with large surf from the E/NE (8-10ft) easing as the coastal low drops southwards, leaving a long fetch of NE-E/NE fetch feeding into a remaining trough line extending through the Tasman up into the Coral Sea.

That would spell days of E/NE surf at moderate levels with offshore winds.

Check back Wed (and in the comments below), we’ll update the situation then.