South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Wednesday Dec 8th)

Forecast Summary (tl;dr)

• Fun E'ly swell building through Thurs, showing best Fri with morning offshores
• E'ly swell plateauing over the weekend with winds tending S'ly
• Building S'ly swells across the MNC on Sat, reaching FNC and SE Qld on Sun
• Small NE cyclone swell Mon/Tues, showing best in SE Qld but stil workable in Northern NSW

Recap

Surf size managed to hang around the 2ft to almost 2-3ft range across Northern NSW both yesterday and today, whilst SE Qld has dipped into the just-rideable range at the swell magnets, with tiny peelers on the outer points. Winds have been generally light through the mornings though Tuesday afternoon saw freshening NE breezes, and today delivered a mid-late morning thru’ early afternoon S’ly change before variable conditions settled in later this afternoon.

This week (Dec 9 - 10)

No major surf is expected from the southern Tasman Sea over the coming days. A developing trough-cum-Tasman Low off the Far Southern NSW Coast on Thursday will generate some sideband SE swell for Southern NSW on Friday, and we may see this encroach the lower Mid North Coast by the afternoon - but it won’t be terribly big.

However, we still have a nice round of east swell on the way for all regions, generated by a sub-topical low positioned well NE of New Zealand over the weekend.

Getting the timing right on the leading edge is always difficult from such distant sources, and some coasts will see it sooner than others - but the afternoon is your best chance for some action, with late 2-3ft+ sets at some of the more reliable swell magnets. It won’t be a great swell for the points, due to the inconsistent and smaller size, but there should be some small peelers if that's your preference. 

Thursday afternoon is also at risk of a northerly breeze (following light/variable conditions early) so Friday is a safer bet across all open beaches with winds expected to swing light NW. Wave heights should persist in and around this size range, just bear in mind the inconsistency. 

This weekend (Dec 11 - 12)

Solid S’ly swells will dominate the charts this weekend as an impressive Tasman Low reaches a peak in strength off the NSW South Coast. 

However, it’ll be aimed mainly into southern East Coast regions, so expect smaller surf in Northern NSW and signifciantly less size again throughout SE Qld.

Fortunately, Friday’s E’ly swell is expected to maintain inconsistent 3ft+ sets at most open beaches over the weekend, thanks to a lengthening of the swell period (related to a peak in wind strength within the core of the sub topical low). Some reliable swell magnets could see rare bigger sets in the 4ft+ range, but they’ll be the exception rather than the rule. Expect long breaks between the bigger waves too.

As for southerly swell potential, the Tasman Low will push into our swell window in the early hours of Saturday morning, which means a gradual increase through the day, biggest on the Mid North Coast with 4-5ft sets by the afternoon at south swell magnets. The steep southerly direction - even S/SW at times - will however create much smaller surf elsewhere. 

This energy should eventually reach the Far North Coast by Sunday morning (though smaller in size, maybe 3-4ft at south swell magnets, smaller elsewhere) however I’m really not expecting much in SE Qld, perhaps the odd 2-3ft set at one or two reliable south swell magnets, with generally E’ly swell dominating otherwise. 

Local winds look good for the outer points both days as a ridge builds along the coast, resulting in moderate SW breezes early mornings, tending S’ly then SE through the day, but with no major strength.

Next week (Dec 13 onwards)

So, the Tasman Low is expected to maintain strength through Sunday before gradually easing. 

As such, Monday should see a continuation of Sunday’s energy, however the southerly fetch (on the low’s western flank) will ease more quickly than the E/SE fetch (on its southern flank, aimed into Far Southern NSW) and this means a more rapid easing of swell across Northern NSW and SE Qld into Monday. 

The weekend’s easterly swell will also gradually ease through this time frame. Moderate SE winds under the influence of the ridge will continue to favourer the outer points on Monday, before light winds settle Tuesday.

Monday and Tuesday have a new, unusual swell source on the cards; long period NE swell generated by a (likely) tropical cyclone expected to spin up in the Coral Sea overnight Friday and into Saturday (see below).

The storm track is pretty good by Coral Sea standards - especially for mid- December! - however its relatively quick passage through the swell window, and the small diameter of the cyclone means it’s a bit of a flukey event, so keep your expectations pegged appropriately. 

At this stage I’m expecting Monday to see building energy from 2-3ft into the 3-4ft+ range at locations with good NE exposure north from Byron, holding Tuesday morning before easing through the day. South from Byron, wave heights should still reach a similar size though the less favourable coastal alignment means there’ll be a smaller number of locations picking up the bulk energy. So, it'll be much more variable in mileage.

Model guidance has this tropical cyclone becoming extra-tropical and approaching New Zealand later Tuesday, where there’s a chance for a broader E/NE fetch on its eastern flank to generate useful swell - but I fear it’s likely to move too fast through our swell window to be a real high quality swell producer. Nevertheless, I’ll keep an eye on this system over the next couple of days and will update on Friday.