South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Friday 7th February)

Best Days: Sat: decent E'ly swells across all coasts (large on the MNC) with light winds for much of the day. Mid-next week onwards: good chance for a large cyclone swell with good winds. 

Recap: As expected, winds were generally out of the south on Thursday, encompassing a slightly broader area than predicted, and providing great waves to sheltered points and southern corners with a building E’ly swell from 3ft to 3-4ft across most coasts. Friday saw a slight rise in size across most coasts with more pronounced 4ft sets, but locations across the Mid North Coast picked up bigger waves in the 5-6ft range. Winds haven’t been too strong either, generally light and variable with lumpy but otherwise quite workable conditions. Oh, and we’ve seen a shit-tonne of rain. 

Stacks of wobbly lines at the Superbank this arvo

Nice lines at Surfers Paradise this afternoon

This weekend (Feb 8 -9)

There’s been a lot of great, real-time discussion in the comments of Monday’s and Wednesday’s Forecast Notes (thanks everyone!), so much so that the weekend outlook is really just recapping what we’ve all been expecting for quite some time. 

Though, there’s still plenty of worthy discussion points for me to elaborate on, so let’s look at the synoptics. 

We’ve got a broad coastal trough, and a stationary high pressure system in the eastern Tasman Sea. Strong E/NE thru’ E’ly winds between the two are building local swells, and with this fetch remaining put for a couple of days, we’ll see a ‘fully developed sea state’, whereby ocean swells reach a theoretical maximum give the fetch length, strength and duration. 

However, we’re anticipating small low pressure systems to develop along the trough line - one of which may evolve into an ECL - and these will display much stronger winds, and will thus generate larger waves heights across narrow regions - though this will be mainly across the Lower Mid North Coast (and locations further south into Southern NSW). Set waves should push 6ft+ here through Saturday and maybe 8ft+ by Sunday. 

North from about Port Mac, we’ll see wave heights ease back through to about Yamba, and then level out, probably around 4-5ft through Saturday, rebuilding to 6ft+ on Sunday as the ridge through the Northern Tasman Sea restrengthens. Size size will probably be a little smaller north from the border though, 3-5ft looks to be an OK ball park size range both days. Perhaps a smidge bigger on Sunday, more around the 4-5ft+ mark at exposed spots, smaller running down the points. 

Of course, the surf outlook means nothing without a grip on local winds, and this is where things get a little fruity. 

The trough is positioned just off the coast at the moment, and is likely to remain here for much of Saturday, ensuring light variable winds. Note: variable means any direction, which could be onshore: but on the balance I think we’re looking at a really good day of strong, punchy and consistent surf.

As the trough moves back ashore on Sunday, it’ll renew E/NE thru’ NE winds and they’re likely to become rather gusty at times. 

So, aim for Saturday as Sunday’s looking to be a write-off. 

Next week (Feb 10 onwards)

The complex trough responsible for this swell (and some bloody large waves in Southern NSW on Sunday) will move south early next week. However the weekend’s firm ridge through the Northern Tasman Sea will remain in place so surf size will probably hold 4-5ft across most coasts into Monday and Tuesday, with bigger 6ft+ sets early Monday across the Mid North Coast. 

Unfortunately, local winds look like they’ll be a problem for some coasts on Monday, remaining out of the NE across Northern NSW, though it’ll be lighter and variable throughout Far Northern NSW and SE Qld. There is a risk it’ll briefly crop up form the north here but on the balance we should see an improvement from Sunday across locations north from about Ballina.

Our downwards trend in the size department will however be temporary. 

A developing tropical cyclone south of the Solomon Islands (today) is expected to slide south, and model guidance has an impressive track right into our NE swell window early Monday morning.

Although this looks even more spectacular on the synoptics - onion rings are certainly the classic definition of a large swell generating weather system - there are a few points of caution we should heed. 

Firstly, the latest model guidance has this system moving a little faster than is ideal for swell generation - the fetch may outrun the swell it’s generating, and therefore it may not realise its full size potential, for the given wind field. In fact, the latest GFS run has this system reaching maximum strength as it slides through our swell window (best aimed to Southern NSW - see below).

Secondly, the exact path of this system is not clear. Some models have it pushing close to the mainland, others have it tracking more towards the eastern Tasman Sea. This will have a bearing on swell size and arrival times, and also local winds. 

Thirdly, we’ll see the a gradual rotation of the swell direction as this system moves through the swell window. So, starting out NE, then ENE, E, E/SE and SE. Model runs with the low off our South Coast mid-late next week are suggesting large return SE swell too, so estimating precise surf sizes where there are two significant swell trains in the water is fraught with difficulties. 

Nevertheless, early indications are for SE Qld to see an initial kick late Tuesday, with surf size reaching a peak on Wednesday. We’ll see this trend kick in across the Mid North Coast a half to one day later (so, building Wednesday, peaking early Thursday). 

As for how much size we’ll see: I’ve got no problems in ball-parking wave heights in and around the 8ft mark (perhaps only beriefly, too) at some point from this event. This may not seem to be much of a call at a week out, but cyclones are inherently more tricky to forecast at long range so I’m hedging my bets here (i.e. a downgrade from this point is still likely to be pretty solid, whilst an upgrade pushes this into the top 10% of regional swell events).

Of course, there's also every chance that the largest waves from such a system may only affect a small percentage of our region. We all know how depressing it is when the local's shithouse, but a couple of hundred kays up (or down) the coast is on the pump, eh? 

I must say though, I am confident we'll see some very large waves, with good winds (S thru' SW quadrant) at some point mid-late next week. 

And, no doubt you’ve seen the 16 day charts - the models have a second powerful tropical cyclone forming in the New Cal/Fiji region next weekend, suggesting our extended run of very solid  NE thru’ E/NE swell may continue for quite some more time.

Enjoy the weekend, stay safe, and I’ll see you Monday!