South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Friday 26th January)

Best Days: Mon onwards: solid combo of building swells from the E/SE, NE, then E plus a S'ly swell later in the week. Biggest days around Wed PM, Thurs. Winds will be best for the points. 

Recap: Our anticipated trade swell has been slower and smaller to develop than expected in Wednesday’s notes. SE Qld beaches have seen small weak waves pushing the 2ft+ mark, however Northern NSW has seen intermittent pulses of S’ly groundswell in the mix. 

Today’s Forecaster Notes are brought to you by Rip Curl.

This weekend (Jan 27th - 28th)

Our in-house surf model is usually pretty good with mid range east and north-east swells, but its accuracy is reliant on source input from the global WaveWatch III model - and it appears that WW3 has majorly overcalled the last few days (estimating 1.7m @ 7+ seconds E/NE for this morning for the Sunshine Coast, which our in-house model converted into 3ft surf). 

In hindsight, surface wind speeds through the lower Coral Sea were right on the border of being useful for swell generation, so I should have been a little more cautious. 

Anyway, the models have also weakened the developing trade flow over the last few days (for Friday and beyond) as it struggles to deal with the developing monsoon trough and its associated lows - and potentially tropical cyclones - spinning off to the south over the short term period. 

So, I’m going to recalibrate the trade swell outlook from today and kick off SE Qld’s weekend outlook starting from a small base on Saturday. The good news though is that the trades will slowly strengthen and also broaden in spatial coverage, so the swell trend will absolutely be upwards over the coming days. 

As per usual under these circumstances, wave heights will be largest across the Sunshine Coast with smaller surf likely as you track south form the Gold Coast. North of Brisbane, we can expect 2ft+ surf early Saturday building to 2-3ft during the day, then 2-3ft+ Sunday morning increasing to 3-4ft+ by Sunday afternoon. 

Expect slightly smaller waves on the Gold and Tweed Coasts, perhaps half to maybe one foot. Minus a little more size as you continue your travels further south. 

Also in the mix this weekend will be a small long range E’ly swell, sourced from a trough NE of New Zealand earlier this week, but it’s not showing up in the model guidance and I’m hesitant to have much confidence due to the modest wind speeds recorded by satellites, and the large travel distance. 

The weekend’s winds will freshen from the E/SE as the trades start to influence the coastal margin, but we’ll see the most strength in the north. Much lighter, almost variable winds are expected at times across the Mid North Coast (direction should be more E/NE Saturday too). Some regions may see isolated pockets of light SW winds in the early mornings, but they’ll be confined to locations south of the southern Gold Coast.  

Next week (Jan 29th onwards)

The model guidance is showing some interesting developments associated with the monsoon trough across the northern Coral Sea. 

Specifically, the lows spinning off to the south are now likely to develop brief swell generating characteristics within SE Qld’s NE swell window. As these developments are expected to occur within the next few days, there’s more confidence that they’ll occur - and we’ll also be able to (hopefully) verify them via satellite scatterometry. 

However, swell generating systems in this region are a rare occurrence, so we have less analogs to work with (i.e. we’re not quite sure how this swell window works, compared to the more frequent east, south-east and south swell windows).

The first low is expected to intensify off the southern Solomon Islands on Saturday, with a reasonable N/NE thru' NE fetch then developing west of Vanuatu and moving south, before the system slides into the swell shadow of New Caledonia Sunday night. That’s a day and a half of swell production, though it is still a reasonable distance from the mainland so we’ll have to wait and see how the weekend scatterometry comes back. 

Regardless, this should generate a NE swell for the start of next week. Model guidance for the Sunshine Coast has a NE swell building from 1.4m @ 11 seconds lunchtime Monday, up to 1.8m early Tuesday. If the numbers are right, this should generate some useful swell in the 3-5ft range though I think it’s probably a little overly optimistic. In any case, NE swells with favourable swell periods react quite different across SE Qld coasts (bypassing some breaks but getting into others quite well) so we’ll have to wait and see what happens. I'll update in the comments below as observational data becomes available.

Anyway, there’ll be a decent trade swell in the mix at the same time. The trades will slowly muscle up over the weekend and we should see 3-5ft E’ly swell across most open SE Qld beaches on Monday (our model has 4-6ft, but I think it’s overcalling the trade swell: 2.9m @ 8.5 seconds seems too much from the responsible fetch). This should hold into Tuesday.

As per the weekend, we’ll see slightly smaller levels of trade swell across Northern NSW, though not as much of a difference as we often see, because the trade flow will extend south to about Sydney latitudes. 

Now: on to the juicy part of the forecast. As the tropical lows/cyclones move south, they’ll merge with a broad trough of low pressure north of New Zealand early next week. This is expected to rapidly strengthen a broad E’ly fetch in our prime swell window, and will generate a solid E’ly (in the south) tending E/SE (in the north) groundswell that’s expected to push through some time Wednesday, ahead of a peak in size on Thursday.

The main risk I see with this system is that the fetch is expected to strengthen as it tracks south, but at the same time a strong front will push north from the Southern Ocean, realigning the tropical system towards the south (away from our swell window). So it may only spend a brief period of time of maturity aimed in a favourable direction for East Coast swell generation, which will limit the swell potential from the strongest part of this weather system's cycle. 

At this stage Wednesday should see early 3-5ft E’ly swell building to 4-6ft across the coast by the afternoon - perhaps a little smaller north of the border away from exposed northern ends, owing to the coastal alignment relative to the swell direction. Wave heights should persist at this size through Thursday, but there’s likely to be a peak of larger waves from the height of the low’s intensification, probably around Thursday lunchtime that could push north of 6ft at some locations south of the border. I don’t think it’ll last very long though (and confidence isn't very high right now that it'll eventuate).

Wave heights will then ease steadily from Friday morning. 

Surface conditions look good for the points Monday and Tuesday with mainly fresh SE tending S/SE winds. and posisble pockets of lighter SW winds early morning. Winds may be more E/SE across southern locations on Monday.

On Wednesday the synoptic flow will likely slacken off, ahead of a gusty S’ly change (tending SE across Far Northern NSW and SE Qld) for Thursday that’s likely to reach 25-30kts across the coast, which will blow out most exposed regions. As such, protected points/southern ends will have the best waves all week. Wednesday's lighter winds will allow for OK conditions at the beachbreaks but it's likely they'll be overpowered anyway. 

The southerly fetch trailing Wednesday’s change will be broad though not overly strong; we should see a rapid increase into the 4-6ft range across Northern NSW by Thursday afternoon, before easing slowly through Friday. 

Anyway, we still need a few more days to iron our the specifics and identify the best windows of opportunity. However it looks like there’ll be waves on the points for just about every day next week. Booya!

See you Monday.