South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Friday 2nd July)

SE Qld Forecast Summary (tl;dr)

• Tricky winds Sat, otherwise great for the points from Sun onwards
• Extended run of E/NE swell through until later next week
• Strong, sizeable pulse late Sun/Mon

Northern NSW Forecast Summary (tl;dr)

• Generally light winds and improving conditions Sat
• Freshening SW tending S'ly winds Sun, then holding moderate SW for the first half of next week
• Extended run of E/NE swell through until later next week
• Large pulse (maybe v.large MNC) late Sun/Mon
• Small S'ly swell later Tues, bigger S'ly swell late Wed/Thurs, then another smaller S'ly swell Fri/Sat

Recap

Stacks of E/NE swell over the last few days, building from 3-4ft to 3-5ft on Tuesday and holding 4-5ft today, but winds have been a little iffy. Thursday morning saw a weak synoptic flow and clean faces within a lumpy lineup at many spots, but other locations were affected by overnight onshores. A regional NE flow freshened into the afternoon, creating messy conditions at most spots and we’ve seen variable conditions today (i.e really good across parts of SE Qld, not so good in Northern NSW) in and around passing rain periods. But, there have been waves!

Sunshine Coast looking super fun today

This weekend (July 3 - 4)

Looking at the synoptics, and the Trough Block™ (that’s a new term I just made up) consists of a broad, elongated trough running the length of the East coast, with an approaching cut-off low to the west of Bass Strait and a large stationary high pressure system over New Zealand. 

A broad ridge extends through the Northern Tasman Sea out to a tropical depression in the South Pacific, which looks impressive on the charts but is ultimately too far away to be a dominant swell source, in what’s a particularly active periods of local activity.

The main point of interest with the trough block is that by the weekend, the head of the fetch will be sitting a couple of hundred kays off the NSW coast, which means local conditions won’t be directly affected by it any more. Additionally, the swell will have had just enough time to iron out the kinks, without losing too much size due to swell decay. It's an ideal setup for swell generation.

Of course, local winds will be affected by other factors but it’s all positive news from here on, we’re past the nasty stuff.

From a swell perspective, the most interesting aspect of this complex Tasman setup is how it’s not really going anywhere. This is unusual for most swell generating systems (mid latitude lows, cold fronts etc), which typically migrate through the swell window, generating a brief flush of swell, or perhaps a one or two day event.

We’re already into our fourth day of trade swell, and the block will remain in place until Monday or Tuesday - so we’ll probably see easterly quadrant energy through until about mid-late next week, albeit smaller by this time. A week and a half at least.. not bad at all.

As for the size trend, I’m still expecting Saturday to hold steady ahead of a building trend Sunday and a peak on Monday morning. However the models have slightly pulled the fetch to the east - away from the mainland - so I’m going to pull back size estimates a bit. However, there’s a good chance that the central Tasman Sea will become close to being ‘fully developed’ by late Sunday and this edges wave height estimates up from the model guidance.

Saturday should maintain 4-5ft+ surf at most open beaches. Sunday’s building trend should peak in the 4-6ft range across SE Qld in the afternoon, with larger 6ft+ surf (after lunch) across Northern NSW, maybe some 6-8ft bombs across the Mid North Coast on dark (smaller earlier).

The only difference in conditions is that Saturday’s looking to see lumpy, leftover but improving conditions with light variable winds. Sunday will see moderate to fresh SW tending S’ly winds as the trough moves east and a front pushes up along the coast. This will favour the points and sheltered southern corners.

Though, the southerly will be delayed in SE Qld and thus so too will be a major improvement of surface conditions, if they become affected by flukey NE winds Saturday arvo (some high res model guidance still has a risk of localised NE gales on Saturday afternoon, mainly the lower Sunshine Coast and possibly northern Gold Coast. So, some bet hedging may be required here).

Next week (July 5 onwards)

So, Sunday’s late upwards trend will peak overnight and then trend down through Monday. Early morning should see 4-6ft surf in SE Qld, 6ft+ surf in Northern NSW with bigger sets across the Mid North Coast though expect an easing trend through the day. 

Conditions look ideal for points and sheltered southern corners with moderate SW winds, possibly tending S’ly through the day but without a lot of strength in SE Qld. 

We’ll then see surf size easing from 4-6ft on Tuesday (Northern NSW), 3-5ft Wednesday and 2-3ft+ Thursday and 2-3ft Friday. Expect slightly smaller surf in SE Qld. 

Also, a series of fresh southerly swells are also due around this time, though they'll mainly benefit Northern NSW.

Initially Tuesday will pick up a small south swell (across the Mid North Coast), from W/SW gales exiting eastern Bass Strait, with occasional 2-3ft sets at south facing beaches by the afternoon. Later Wednesday and Thursday should see larger south swells from a series of broad, powerful fronts below Tasmania from Monday onwards, that should reach a peak in the 4-5ft range at south facing beaches south of Byron.

A secondary polar front/low below the Tasman Sea mid-week will maintain strong though smaller southerly swells through Friday and Saturday. 

So all in all, a fantastic week of waves coming up.

Have a great weekend, see you Monday!