South East Queensland and Northern New South Wales Surf Forecast by Ben Matson (issued Monday 4th January)

Best Days: Look, there'll be waves most days but the wind forecast is tricky and with six or seven individual swell sources it's hard to get too specific. There'll also be a wide range in size with some swells favouring one coast over another, however the take home items are: Northern NSW (north of Coffs) looks good Tues and maybe early Wed, and Southern Qld points look good later Wed/Thurs/Fri, and the weekend looks great for Northern NSW and probably SE Qld, though generally small north of the border.

Recap: Hands up who scored great waves over the weekend? The E tending E/SE then SE groundswell generally came in very close to forecast expectations, though the Sunshine Coast’s inner points (re: Noosa) didn’t show up anything at all early Saturday, which is perplexing given the size elsewhere and the initially strong E’ly swell direction. Otherwise, pretty much every other coast was pumping with 4-5ft surf across the Gold Coast and solid 6ft sets south of Byron on Saturday, and fantastic point breaks across the Mid North Coast too (keep an eye out for a gallery tomorrow). Surf size tapered off into Sunday but still remained strong, but we saw a little more size loss today north of the border than expected (generally 2ft against a forecast of 2-3ft). Northern NSW has however remained within forecast expectations and we’re now seeing a rebuilding short range SE swell of a ridge in the central Tasman Sea. 

This week (January 5th - 8th)

Lots of surf on the way (again!) with a dynamic forecast period ahead. There are several sources of swell so let’s take a look at them one by one - this is a different format to the usual notes but I thought it may be a better way to get it all down:

1. Broad ridge through the Tasman Sea

This ridge is also linked to a coastal trough (which gave us a good dose of rain yesterday; flood warnings are also out for the lower Mid North Coast right now) and it stretches almost the entire width of the Tasman Sea. The fetch's length - and its impressive girth - makes up for the generally modest wind speeds. We’re already seeing an increase in size off the Mid North Coast, and surf size should increase throughout Tuesday across the North Coast and SE Qld, though size will be somewhat limited north of the border due to the direction (not bad, but not perfect). 

Overall swell trend: upwards throughout Tuesday, reaching 4-6ft across the exposed beaches of the Mid North Coast, 3-5ft across the Northern Rivers, and 3ft across SE Qld (mainly outer points and exposed beaches; much smaller across sheltered/inner points).

Winds: Very tricky right across the region, especially Queensland due to a second coastal trough across Central Queensland waters that’s due to to track SE and briefly influence SE Qld waters for a period on Tuesday. This may result in a period of NE winds at times however it may only extend as far south as the Sunshine Coast.

Elsewhere, the primary coastal trough along the NSW coast should allow light variable winds to the north of the trough axis (about Coffs Harbour) but freshening E/NE winds are likely south of this, and may become strong around Seal Rocks. A low is expected to form near this region late Tuesday afternoon, and this will probably influence the wind field in all areas at some point, of which it’s too hard to have any certainty in what'll eventuate - but most regions apart from the Lower Mid North should see periods of light variable winds at times. 

2. STC Ula

Severe Tropical Cyclone Ula is still at Category 3 status, and is expected to maintain strength through Tuesday before weakening slowly on Thursday and Friday. 

Its swell generating potential is still limited by its small diameter as well as the considerable travel distance from the source to the mainland. However the supporting ridge to the south of the cyclone over the last few days has been sufficient enough to generate a good quality range of swells that should arrive after the long period swell from STC Ula itself, and provide useful easterly swells through the latter half of the week.

Truth be told: I don’t think we’re going to see quite as good surf from STC Ula as previous expected. This is mainly due to the mix of swells (mentioned above and below) concurrently in the water, plus a tricky wind outlook with an advancing southerly change. This will likely limit the best waves to the southern Gold Coast points (again!) through the afternoon, though anything is really possible ahead of the change. 

For the most part we’re looking at a peaky combo of swells from the east and southeast in the 3-4ft range on Wednesday (including some leftover swell from Tuesday's ridge swell above), though we may see much larger waves originating from the core of STC Ula every fifteen or twenty minutes, anywhere between 4ft and 6ft at the momre relaible swell magnets.

However I wouldn’t expect too many of these bigger waves to show up: the core winds were contained over a very small region and despite the suggested captured fetch scenario, I simply haven’t been able to find  enough complementary satellite data to support the notion of bigger waves. Can't rule it out though.

To delve into the local wind problem a little more - the coastal Qld trough may still influence the Sunshine Coast’s winds on Wednesday morning too - there is a risk of NE winds at some point. Along the Northern NSW coast, we’re looking at a gusty southerly reaching Coffs Harbour early morning, then Byron just after lunch and the Gold Coast shortly afterwards. The latest models suggest it’ll taper off north of here; swinging winds to a moderate easterly throughout the afternoon on the Sunshine Coast. 

Periods of variable winds are certainly possible ahead of the change but in general you’ll just have to watch the obs and pounce if and when you see something ticking the boxes of your local.

TC Ula is expected to meander through the SW Pacific for some time, but may eventually tuck inside the swell shadow of New Caledonia on Thursday or Friday - which means any inconsistent energy we see from it will probably dry up later in the weekend. But as I’ve mentioned above, most of the swell we’ll see from this system will be from the supporting ridge so I wouldn’t weight too heavily on TC Ula as a primary swell source, especially given the large number of other swell generating systems on offer this forecast period.

3. Developing low within the coastal NSW trough

This system looks great on the synoptic charts but I’m not particularly in favour of its track. The low is modelled to reach peak intensity later Wednesday - with most of its fetch aimed either into the Sydney/Hunter coast, or straight south in direction along the Northern NSW coast - before the low then tracks south-east and is absorbed by a passing series of fronts associated with an amplifying long wave trough. 

We should see a kick in southerly swell across Northern NSW later Wednesday  (initially Mid North Coast) and into Thursday (rest of North Coast) with residual S/SE swell off the back of thew low filling in throughout Thursday (Mid North Coast) and Friday (rest of North Coast, exposed parts of SE Qld coast). But on the whole, the strong southerly swell direction and the accompanying S/SE winds from Thursday onwards will render most breaks (picking up this swell) quite choppy. 

4. Southerly groundswell for the weekend

A strong series of fronts pushing up under the Tasman Low should generate a strong south swell for the weekend (peaking Sat, easing Sun), mainly favouring Northern NSW but with set waves somewhere in the 3-5ft range at exposed south swell magnets. The acute southerly direction will limit size at remaining beaches and I don’t think we’ll see much of this in SE Qld, but that’s OK as there’ll be plenty of residual east swell on offer. 

Winds look good for the weekend too - light and variable across Northern NSW, and pretty good in SE Qld too - perhaps a lingering SE flow on Saturday (with early morning SW’ers) but tending light and variable for Sunday.

Another smaller followup S/SE swell is due early in the following week from a trailing front in the southern Tasman Sea later Friday and early Saturday, but I’ll take a closer look at that in Wednesday’s notes.