Sydney Hunter Illawarra Surf Forecast by Ben Matson (issued Mon 11th Apr)

Forecast Summary (tl;dr)

• Strong E'ly swell Tues, easing from Wed
• Fresh S'ly winds Tues, easing steadily into Wed though lingering SE into Thurs (mainly north from Sydney, light/variable south from here)
• Strong S'ly groundswell Thurs, easing Fri
• Building E'ly swell over the weekend (gen light winds), peaking Sun, easing Mon
• More S'ly swell over the weekend, but acute in direction
• Long term suggests typical autumn south swell pattern

Recap

Onshore winds created messy conditions on Saturday with a building E’ly swell and steady S’ly swell, but a swing in the breeze to the NW on Sunday cleaned up the surf nicely, and we’ve seen similarly smooth conditions this morning. Wave heights have fluctuated in the 3-5ft range out of the east through this period (plus the south swell on Sat) though there’ve been periods of stronger surf pushing more prominently at the top end of this range, occasionally bigger (such as today, which reached 4-6ft this afternoon). 

This week (Apr 12 - 15)

TC Fili is still active within our swell window, and will probably only transit into the New Zealand swell shadow tomorrow, which means some form of east swell all week. 

We’ve got another strong pulse expected to fill in tomorrow, of a similar size as per today, though the timing is not clear and some locations may miss out on the early session (though, residual swell should still manage 3-5ft). Otherwise, we’re looking at 4-6ft surf on Tuesday, easing from 3-5ft to 3-4ft on Wednesday, then 2-3ft by Thursday. 

Tuesday will see wind issues at exposed beaches thanks to a shallow southerly change pushing up the coast tonight, focusing the best waves to sheltered southern ends. The breeze will abate through the day but it’ll take a while for conditions to improve. A small spike of short range southerly swell will trail the change but the east swell will be dominant. 

Lingering S’ly tending SE winds on Wednesday should be light enough for pockets of early SW winds (mainly Northern Beaches), with easing swell energy from the same quadrant once again being smaller than the dominant E’ly swell. Expect lumpy but OK surf in general.

A firm ridge will become established across the Northern NSW coast later Wednesday, but it shouldn’t affect the coast south from Sydney. We’ll see easing winds through into Thursday though a risk of moderate SE breezes will remain north of the harbour during both days.

At the same time, a long period S’ly groundswell will push through (Thursday), generated by a deep low well south of Tasmania today. We can expect a wide range in size from this swell (with long breaks between sets), up to 3-5ft at south facing beaches though the long periods should amplify wave heights at offshore bombies and reliable south swell magnets (so, don’t rule out sneaky 6ft+ sets here). However beaches not open to the south will be much smaller.

Easter Friday should then deliver good waves with light variable winds and a secondary pulse of southerly swell from another deep low south of Tasmania, though much less favourably aligned than the system generating Thursday’s energy. As such wave heights will come in a couple of feet smaller, mixing up the beaches nicely with the small leftover east swell.

And.. a deepening trough in the northern Tasman Sea may generate some fresh E/NE swell too, though this is more likely to push through on Saturday.

This weekend (Apr 16 - 17)

Plenty of swell due this weekend, with likely clean conditions under a slack pressure gradient.

The main synoptic feature is a deepening surface trough across the northern Tasman Sea from Thursday onwards, that will intensify and drift south into our swell window on Friday. It’ll be best aimed towards Northern NSW and SE Qld, but we’ll see a healthy spread of size into our region, and current expectations are for an upwards trend all day Saturday towards a peak on Sunday, maybe 4-5ft at open beaches, and some bigger sets north from Sydney into the Hunter.

Also due over the weekend, originating from an intensifying frontal system below Tasmania (Friday) that’ll reach maturity as it reaches New Zealand by Saturday, is a strong sideband southerly swell, offering a wide range in wave heights owing to the flukey swell source. Some locations may dip out completely but reliable south swell magnets could pick up 3-5ft sets.

I’ll revise all of the specifics on Wednesday.

Next week (Apr 18 onwards)

Long term is suggesting an amplifying Long Wave Trough over the eastern states during the first half of next week, and a steady supply of frontal systems generating back-to-back southerly swells through the second half of the week. Certainly can’t see any shortage of swell ahead, anyway!

See you Wednesday.