Complicated mix of swells in the forecast period

Ben Matson picture
Ben Matson (thermalben)

Southeast Queensland and Northern New South Wales Surf Forecast by Ben Matson (issued Friday 4th June)

Best Days: Sat/Sun: small mix of south swells at exposed beaches in Northern NSW with good winds (not much in SE Qld). Late Mon/Tues/Wed: small SE swell in Northern NSW with generally good winds (not much in SE Qld). Thurs/Fri: building combo of swells from the SE and E, with good winds. Next Sat/Sun/Mon/Tues: potential for more fun long range E'ly swell.

Recap: More of the same - plenty of south swell at exposed beaches, smaller elsewhere and especially in SE Qld away from the swell magnets.

This weekend (July 5-6)

The weekend’s looking fun if you’ve got a good south swell magnet up your sleeve. 

Aside from easing residual S/SE swell from today, we’ve got a small pulse of new S/SE groundswell due to arrive through Saturday morning. This was generated by a small cut off low that formed well south of New Zealand during the middle of the week, and merged with the fronts responsible for our most recent southerly swells. 

The low developed a tight S/SE fetch that generated a small new event that’s due to arrive in southern NSW over the coming hours, before reaching the Mid North Coast overnight and the North Coast early Saturday morning. Set waves should manage 2ft+ at south facing beaches but there’ll be long breaks between waves, and it’ll be much smaller away from these sources. Expect very small surf in SE Qld (maybe a few small peaks at the swell magnets).

Another small, flukey swell source is lining up for Sunday afternoon. A small but intense Southern Ocean low is tracking up through the southern Tasman Sea towards southern NZ, and while not very well aligned for the East Coast, it’ll generate some sideband energy that’s expected to glance the coast throughout the day. This swell will probably be even less consistent than Saturday’s, but south facing beaches may again pick up very inconsistent 2-3ft sets at times. However, expect smaller surf early morning.

Next week (July 7-11)

Next week’s surf prospects look very interesting right across the East Coast however - despite assurances in Wednesday’s forecast to the contrary - I now have some concerns for northern regions, particularly SE Qld at least to begin with. However we are certainly on target for a reasonable, if not decent east swell within the next week and a half… so read on.

Over the weekend, a stationary E/SE fetch is modelled to develop east of Bass Strait, in conjunction with a broad trough of low pressure across the southern Tasman Sea and a strong high pressure right to the south, at polar latitudes. This (slightly unusual) synoptic setup will generate a good SE swell for the southern half of NSW but wave heights will taper off across Northern NSW due to the alignment and location of the responsible fetch. 

The Mid North Coast should see an increase into the 3ft+ range at exposed south facing beaches during Monday afternoon but I think surf size will become smaller north of about Coffs or Yamba, and it'll be very small indeed in SE Qld. Expect smaller surf in the morning - especially in the North - ahead of an afternoon peak. Conditions should be OK with moderate to fresh W/SW tending SW winds in conjunction with a developing low off the South Coast of NSW.

Surf size will then slowly ease through Tuesday, along with lighter offshore winds as a ridge builds across the coast.

On Monday, a secondary E’ly fetch is modelled to develop immediately west of Cook Strait. This is forecast to generate a slightly smaller E/SE swell for the East Coast on Wednesday. However, it looks like this fetch will be aimed more towards Tasmania’s East Coast and I fear the Northern NSW coast (and more so SE Qld) will dip out due to the poor aligment of the fetch. Still, there should be some small residual SE swell on offer in Northern NSW, and conditions will be good with light offshore winds.

While all of this is going on, a broad region of tropical activity south of New Caledonia is expected to drift south towards New Zealand, consolidating with the system west of Cook Strait by Tuesday. This is expected to develop a powerful E’ly fetch off the west coast of New Zealand mid-week, but current model guidance suggests it’ll initially be aimed towards the southern NSW coast. We will see a smaller percentage of SE swell fill into the North Coast around Thursday, say somewhere in the 3ft+ range in Northern NSW and smaller in SE Qld.

Of much greater interest to the Northern NSW and SE Qld coasts is the early and latter stages of this developing system. A broad ridge of high pressure across NZ’s East Coast on Monday will steer fresh to strong E/NE winds through our far east swell window during the middle of the week, which should result in a reasonable east swell building around the same time (Thursday) and holding into Friday. No great size is expected but it should otherwise fill the void at open beaches.

Long term (July 12 onwards)

Furthermore, this slow moving system is then expected to park itself just NE of New Zealand  through the middle to latter part of next week, aiming a band of easterly gales towards our coast. This should result in a slightly bigger easterly groundswell arriving next weekend and holding through the start of the following week.

Now, this outlook is not without some complications. Firstly, the model data is divergent on exactly where this system will set up camp next week - and small differences in model output will have major ramifications in the surf forecast, because the fetch is likely to be somewhat bisected by the landmass of New Zealand. So, there’s a chance that future updates will push the system south and cut off most of the swell potential: we can't rule that out right now.

That being said, the overall synoptic pattern looks slow through this time frame and I’m reasonably confident that we’ll see at least a modest fetch develop inside out swell window, resulting in some fun groundswell for the open beaches through the latter part of next week, the weekend and the start of the following week. Let’s see how things are looking in Monday’s updated forecast.

One other area to keep an eye out for in the longer term: a strong low moving through Bass Strait mid-late next week looks like following a similar storm track to what we saw over the last few weeks. That is - quite north in latitude, meaning small, flukier activity within our less reliable south swell windows (and only for Northern NSW).


mitchvg's picture
mitchvg's picture
mitchvg Sunday, 6 Jul 2014 at 9:55pm

ACCESS feeding in some moisture to NW WA next Sat, precursor to those 3 magic words...?

mitchvg's picture
mitchvg's picture
mitchvg Sunday, 6 Jul 2014 at 10:15pm

Also, ZENSAN! Anything heading you way off this typhoon?