Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 22nd May)

Best Days: Tues: easing SE swell with mainly light winds. Wed/Thurs: clean but small leftover beachies. Fri/Sat: minor bump from the E/NE with light variable winds tending NW over the weekend

Recap: The weekend delivered plenty of fun waves. Conditions were initially a little bumpy on Saturday morning but it cleaned up into the afternoon and Sunday was generally pretty good with offshore winds through the morning and light onshores in the afternoon. A combination of south and north-east swell maintained 3ft sets on Saturday, with the NE swell easing a little into Sunday but a second south swell holding size relatively steady. Last night, an incredible long period SE swell pushed up into the Tasman Sea, generated by a third polar low in a Southern Ocean sequence, which tracked underneath New Zealand on Friday (the first two generated the Fri/Sat and then Sun south swells). A wave buoy well south of New Zealand recorded maximum wave of heights of 19.4m (68ft!) on Saturday with peak swell periods of 17 seconds. The Sydney wave buoy displayed forerunners of 20 seconds (!) overnight Sunday, levelling out at 16-18 seconds for much of today and the resulting surf has been incredible, if somewhat inconsistent with 4-6ft waves across most open beaches and some swell magnets raking in bombs sets well north of 6ft+. Winds were light offshore through the morning but are now light onshore.

Morning sets at Maroubra, via our surfcam

This week (Tues 23rd - Fri  26th)

What a swell event! Not so much in the actual surf size, but in the metrics recorded across the coast. The fetch that generated this swell was not unusually strong (fairly standard 40-50kts+ core winds); more interesting was its alignment and projection through a rare part of our distant SE swell window. And it had the added benefit on working on a very active sea state generated by the previous fronts. We often see small flukey swells from this region but it's rare for such a large long period swell to originate from this region - normally the low latitude westerlies absorb any weather system trying to develop a southerly or south-east fetch here.

Anyway, our wave model (and therefore, by default our surf model) undercalled this event - though as expected (my Friday notes pegged 6ft+ sets for exposed spots this afternoon) - but it also missed the arrival time too, and the peak of the swell - anticipating a peak later this afternoon and holding into Tuesday morning. In reality the swell came in six to ten hours hours ahead of schedule and was much bigger than model guidance indicated.

And this forms the crux for the initial short term forecasting decision - how much size will hold true overnight? We’re already seeing a slow easing across some of the southern NSW wave buoys, but not all. Also compounding the issue is the sheer inconsistency of the swell, which will become even more prominent over the coming 24 hours.

Realistically speaking, the current swell is certainly the most significant energy we’re expecting all week and with generally light winds for much of tomorrow (moderate N’lies are possible on the South Coast) it’ll be well worth making the most of things. 

I think we’ll probably see some very inconsistent 3-5ft sets at south facing beaches early morning - let me emphasise the “very inconsistent” part here - before size tails off 2-3ft by the afternoon. Expect smaller surf at remaining beaches, and also probably across exposed locations south of about Wollongong (as the swell will "dry up" here earlier than northern latitudes).

However there will also be a small undercurrent of long range trade swell that provided great waves across Northern NSW and SE Qld over the last few days (inconsistent 1-2ft sets at most southern NSW beaches). 

Winds will then swing W’ly on Wednesday and variable for the end of the week. A small, vigorous front exiting eastern Bass Straight on Wednesday may provide a brief flush of small new south swell for Thursday (inconsistent 2ft+ sets at south facing beaches) but other than that the other interesting region I’ll be watching all week is the South Pacific where we’re looking at a late season tropical low forming near Fiji over the coming days, strengthening the already-broad trade flow between it and New Zealand before it tracks eastwards.

This is expected to reach a peak in strength later Tuesday and therefore should show as a reasonable pulse of E/NE swell across our coast around Friday (we’ll see a small undercurrent of trade swell all week, prior to this). Friday’s sets should push up into the 2-3ft+ range though once again will be very inconsistent owing to the large travel distance. But with light winds there should be some fun, albeit slow waves around the traps.

This weekend (Sat 27th - Sun 28th)

Friday’s E/NE pulse is expected to hold through much of the weekend with extremely inconsistent but otherwise fun waves in and around the 2-3ft range. A large Tasman high and an approaching front from the west should steer winds around to the NW, creating clean conditions.

I’m not expecting much swell from the south this weekend; a minor front pushing east of Tasmania on Thursday afternoon may generate a minor pulse for Saturday but I doubt there’ll be much more than 1-2ft in it at south swell magnets. 

Next week (Mon 29th onwards)

Another cold outbreak is on the cards for early next week which also suggests a strong southerly swell for the middle of next week as a strong southerly fetch pushes up east of Tasmania. 

Otherwise, there’s nothing else of any major concern showing up on the long range charts.