Stacks of swells ahead, though windy until Monday

Ben Matson picture
Ben Matson (thermalben)

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

Best Days: Most days will have plenty of waves for the protected points. Lots of swell for next week with likely similar winds. Possible NE swell later next week from a Coral Sea cyclone.

Recap: A small E’ly swell provided fun waves at outer points Tuesday, with strengthening SE winds today accompanying a building trade swell, biggest across Northern NSW and with increasing opportunities across the SE Qld points as the day wears on. 

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

Late afternoon sets at Currumbin

This week and weekend (Mar 7-10)

No changes to Monday’s forecast, as a steady synoptic pattern prevails for the rest of the week. 

A large high pressure system over Tasmania extends a broad ridge through the Tasman Sea, driving strong SE winds into the Coral Sea. This is building strong mid-range SE swells across the region, that are very wind affected throughout Northern NSW, but ideal for the sheltered points in the Far North and across SE Qld. 

Wave heights should remain somewhere around 4-5ft at open beaches south of Byron from now thru’ Sunday, and SE Qld is looking a spread of surf size depending on your beach/point’s level of exposure. Open stretches should push up into the 4ft+ range but most outer points will see wave heights in the 3-4ft range, with the more protected points seeing smaller surf. 

Winds will remain fresh and gusty from the SE right throughout the period, only beginning to ease across the Mid North Coast over the weekend (and even then, still holding from the SE). As such it’s an extended period well suited to protected locations. 

As for swell sources besides the primary Tasman Sea ridge, we’ll also see a small E’ly pulse on Friday from a minor E’ly fetch exiting western Cook Strait today, though wave heights probably won’t boost much about the existing trade swell. 

There’s a more curious swell source on the cards for Northern NSW, that was missed in Monday’s notes and is showing up in the model guidance for the end of the week. It's a small long period S’ly event that's due to arrive on Friday, originating from a poorly aligned but intense Southern Ocean low that displayed 50kt winds over the last few days, well SW of Tasmania. 

Ordinarily, gale force westerly fetches from this quadrant of the Southern Ocean can be routinely ignored for Northern NSW’s surf potential, but there was enough W/SW alignment in the supporting fetch to give it some credibility. And with models estimating 0.9m @ 15.6 seconds S/SW (192 degrees) at Coffs Harbour around lunchtime, it certainly can’t be ignored. However whatever south swell makes landfall (say, occ 3ft+ sets and only at reliable south swell magnets south of Byron) will be masked by the more dominant trade swells. This swell will then ease slowly through the weekend

Next week (Mar 11 onwards)

We’ve got plenty of action in store for next week.

TC Hola is intensifying near Vanuatu at the moment, but will veer SE and track perpendicularly at speed through our swell window from New Caledonia to New Zealand over the weekend. 

As such, the cyclone itself isn’t a major source of new swell, but as it pushes towards New Zealand it’ll strengthen a ridge off the North Island, and the swell potential from this source has increased since Monday's outlook.

As the weekend’s trade swell slowly eases through the first half of next week, we’ll see new energy from this NZ fetch slowly build through Monday ahead of a peak into Tuesday, possibly holding into Wednesday morning. Wave heights will be biggest across far Northern NSW south to about Coffs, with sets in the 3-5ft range. Across SE Qld, we’re looking at solid lines of 3-4ft swell across the outer points (slightly bigger at exposed northern ends), but smaller across the inner points. However, compared to the current trade swell, it'll be a little less consistent due to the more distant swell source. 

Also in the mix next week - but exclusively for Northern NSW - will be some new southerly groundswell, generated by a series of strong fronts approaching the southern Tasman Sea early next week. This should provide 3-4ft+ sets at south swell magnets south of Byron around Wednesday, with the combined E/SE and S’ly swell trains possibly creating some bigger waves at reliable swell magnets. Easing size is expected into Thursday.

Winds look OK to begin with, with moderate S’ly tending SE winds across SE Qld, and lighter to moderate SW tending SE winds throughout Northern NSW (becoming variable across the Mid North Coast). 

However, a developing tropical system in the Coral Sea track over the weekend will track southwards early next week, and by Tuesday and Wednesday we’ll see some influence on the local winds across SE Qld - freshening from the E/SE. It’s hard to say whether it’ll influence Northern NSW (south from Byron) but that’s certainly a possibility too. 

Of more interest is whether this tropical system will develop into a Tropical Cyclone. Model guidance has been pretty good with it over the last few days, and we’re certainly looking at a reasonable swell source in our NE swell window through the middle of the week, but what’s not yet clear is how this system will evolve - and that has a bearing on the kinds of swell we might see across SE Qld (and to a lesser degree, Northern NSW).

Two possible outcomes are either a NE groundswell (from a fully formed, slow moving Tropical Cyclone), or instead we may just see a spread of E/NE swell from a broader supporting E’ly fetch below a smaller tropical low (or cyclone). This energy looks like it’ll impact the region later next week, but its too early to pin down size estimates and local conditions. 

Either way we have a bucketload of swell in store for the next two weeks, which is great timing for the Quik Pro!

See you Friday. 

Comments

donweather's picture
donweather's picture
donweather Wednesday, 7 Mar 2018 at 8:42pm

Ben just wondering why of late you appear to solely be reporting on the GFS model with no reference to the other models forecasts outliers etc. Every other model except GFS hasn't had the Coral Sea TC on its charts for the last few days of model runs. GFS keeps bouncing around with it so it would appear it's a very wild outlier of eventuatinf at best and your forecast above appears as if it's set in stone.

thermalben's picture
thermalben's picture
thermalben Wednesday, 7 Mar 2018 at 9:05pm

GFS has been performing pretty well of late, so I haven’t felt quite the need to outline every possibility across all of the models, especially when the short to mid term forecast is pretty stable.

Sprout's picture
Sprout's picture
Sprout Wednesday, 7 Mar 2018 at 9:43pm

Yawn. Wake me if we ever get offshores again.

Sprout's picture
Sprout's picture
Sprout Friday, 9 Mar 2018 at 3:42pm

Wait, what?

balsabarrel's picture
balsabarrel's picture
balsabarrel Friday, 9 Mar 2018 at 5:06pm

It was a big lunch but I'v got some US models showing me a cat 1/2 150 nm due east of Noosa on Wednesday 14th around midnight generating 10m+ at its centre with 4/5m reaching the coast . A fast moving system with a 'close' sweep of the Sunny Coast . Dont tell me I'm dreaming Ben .

donweather's picture
donweather's picture
donweather Friday, 9 Mar 2018 at 5:06pm

No question GFS being the most bullish with the Coral Sea TC. EC has a weak cyclone crossing up near Mackay with much MUCH less swell potential for us than GFS. UKMET not even interested in a Coral Sea TC at present. I see we've all forgotten about Hola.