Massive, windy surf from TC Oma on the way
South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Wednesday 20th February)
Best Days: Make the most of Thursday, as all bets are off from Friday through Monday: large trending very large to possibly massive surf, storm force winds and Victory-At-Sea conditions.
Recap: Tuesday delivered fantastic E’ly swells with light winds and sea breezes, and wave heights around the 3-4ft+ mark at exposed beaches in the north, smaller south from Ballina. Size eased to around 3ft this morning (and has abated a little more throughout the day), with smaller surf south from Ballina again. The leading edge of cyclone swell from TC Oma appears to have recently reached the Sunshine Coast, and is showing nicely on the Noosa surfcam (see images below, from about 4:30pm). There is (as yet) no sign of any energy on the buoys (though there is a delay on data feeds).
Noosa this afternoon
This week and weekend (Feb 21 onwards)
Let’s be honest: these synoptic patterns are exhausting. Refreshing the buoy data and patiently watching the surfcams is an unusual method to drain the senses, but there ya go. I'm all out of nervous energy, and the surf's still small.
Anyway, I’ve already written a lot about TC Oma over the last week, including many theories about what may or may not happen from a number of scenarios.
As an example, one overlooked aspect (because it didn’t have an associated swell event) was the assessment of the barrier influence of the Chesterfield Islands - as suspected, it blocked all of the upstream NE swell generated near Vanuatu. But, coming to that conclusion requires as much analysis as estimating probable wave heights from TC Oma once it reaches maturity off the SE Qld coast.
On Wednesday, the forecast-decision-making-process had reached a crux: the previous near-rock-solid New Zealand trajectory was now at risk with ECMWF suggesting a stalling phase east from Byron Bay, and then a recurve back to the north-west.
As it turns out, EC was leading the pack: most of the other models have since followed suite.
Although now we’ve got that curveball partly out of the way, there’s a million other variables that may have a significant bearing on surf potential throughout the forecast period.
And to be honest, the SE Qld and Far Northern NSW coasts simply aren’t conditioned for swell events (and their accompanying winds) of this magnitude. Not only are we going to see a major disfiguration of many exposed coasts, there simply won’t be very many surf breaks handling this swell event.
I’d harbour a guess that the vast majority of surfers won’t actually surf between Friday and Monday or Tuesday because it’ll simply be too big and too windy. Unlike other Australian coasts, SE Qld and Far Northern NSW have a distinct shortage of locations that offer significant protection and shelter under exceptional swell events. And, most surfers are well and truly out of their comfort zone once wave heights are north of 6-8ft (me included!).
So on to the particulars: TC Oma is tracking towards SE Qld, at a speed conducive for a captured fetch scenario, which should enhance wave heights from its southern flank (the E/NE fetch). With 40-50kts within our swell window (core winds speeds are even higher), we’re going to see more than the 11-13 second swell periods at the coast, as estimated by the models (though not as high as the theoretical maximum, given the short travel distance).
I’m really not that confident on the actual size/timing split, but the E/NE swell trend will be upwards from Thursday into Friday, and then holding into Saturday and Sunday. This particular component will probably max out in the 8-10ft+ range across exposed coasts. Expect smaller surf through Thursday (say, building from 5-6ft to 6-8ft+), with smaller waves across protected spots.
As TC Oma pushes close to the coast, we’ll see strengthening southerly quadrant winds between it and the mainland (more S/SE across the Mid North Coast, but possibly even S/SW across northern regions such as the Sunny Coast). As a side note, these winds will need to be considered as to how they could affect local conditions at some breaks that may otherwise be instantly lighting up your radar.
At this stage later Friday, Saturday and Sunday could see storm force winds or greater, with destructive conditions across some exposed and/or elevated spots. Don’t take this for granted - it’s not an ordinary bout of gusty winds, it’s a slow moving, broad scale and long-lived pattern of dangerous weather conditions that will negatively affect the region for quite a while. The cumulative effect of very strong wind episodes of this magnitude is not a common occurence.
The other obvious by-product of this strengthening fetch is the generation is a very large secondary (tending primary) local SE thru’ S/SE swell.
Because the fetch will be on SE Qld’s doorstep, it’s hard to estimate wave heights. I’ll be brutally honest: I haven’t seen the models prog a system like this in our near swell window before, so all bets are off. Could be 15ft. Could be 20ft+. Most forecasting rules are out the window because we don’t know if a storm of this magnitude will have enough travel distance to generate truly huge surf (though sea/swell conditions recorded by wave buoys will likely break records over the coming week).
But with 40-50kts or more of sideshore wind, does it matter anyway?
This is one of those swells that could be too big for locations that rarely break. Anything is possible. I’m really not keen on hyperbole, but I’m also not one to sit on the fence - I can only call it as I see it. And that is, expect nothing short of Victory-At-Sea conditions just about everywhere with any kind of open exposure. To reiterate the obvious: don’t expect to surf much, if at all.
As a side note, the strongest part of the fetch will be mainly north from Byron, so because of the alignment, expect smaller surf and a little less wind (relatively speaking) as you head south from here.
To cap things off further, the weekend will see an unrelated southerly swell south of the border from a front entering the lower Tasman Sea. It’ll add another 4-6ft at south facing beaches.
And next week?
Anything is possible.
The latest GFS model run has TC tracking north-east of Fraser Island for a few days and then coming in for a second swing at the Sunshine and Gold Coasts later in the week (yes, really!), suggesting a possible coastal crossing across Stradbroke Island next Saturday. The other models meander the low further north with a possible coastal crossing around Mackay.
Whilst either of these specific scenarios is unlikely, it can’t be ruled out given the massive model variations in the last few days.
So the take home long term message is: we've got high uncertainty for all of next week, but regardless, TC Oma will remain some kind of influence for quite some time. We’re just not sure whether it’ll maintain very large surf, or just standard background easterly swell in the wake of its tour de force through the Coral Sea.
What a week!
See you Friday (and in the comments below prior to then).