South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Monday 10th March)

Best Days: Should be decent surf most days at most coasts, as long as you can find some protection from the predominant southerly breeze (maybe not Tuesday, south of Yamba, as we'll be between swells at this point in this region). Keep an eye out for the Wed PM/Thurs E/NE swell from TC Cook. Coupled in with a secondary SE swell it'll provide some excellent A-frames up and down the beaches. 

Recap: The weekend played out as expected with easing E/SE swells across Northern NSW but a building trade swell across SE Qld that delivered excellent surf to most beaches between Far Northern NSW and SE Qld on Sunday and even this morning, though we have seen a drop in size overnight. Early winds were offshore with sea breezes each day. 

This week (Apr 11 - 14)

I’m enjoying this different format for a change, so let’s keep it running through this week. Essentially, each paragraph relates to a particular swell event or other weather feature that will in some way influence our surf prospects. 

Easing trade swell

The fetch responsible for our current trade swell is all gone so expect a gradual easing from this source into tomorrow. However, we are seeing some reinforcement from the tail end of the fetch further east over the weekend - which is expected to draw out the swell periods another second or thereabouts. So despite an overall easing of swell size, we may see SE Qld open beaches persist in and around the 2ft mark, with very occasional bigger 2-3ft sets at swell magnets. It's likely to be quite tidally affected too.

Tasman Low - stage 1

A Tasman Low will form off the Far Southern NSW Coast tonight. This won’t properly extend into Northern NSW’s immediate south swell window until late Tuesday so we’re not looking at a decent swell increase until Wednesday across most regions (maybe late Tuesday south of Coffs, but very wind affected). As it is, the strongest winds will develop close to the South Coast so wave heights will be slightly tempered north of Seal Rocks compared to south due ot the shadowing effects of the Hunter curve. 

Surf size should build to a windy 4-6ft at south facing beaches south of Byron on Wednesday morning, then ease throughout the day (a little later in the Far North). Expect much smaller surf at protected beaches, and I’m not expecting a lot of size north of the border due to the low swell period and southerly swell direction. Outer Gold Coast points may pick up some stray 2ft+ sets, it’ll be bigger but wind affected at exposed northern ends and most Gold Coast/Sunshine Coast beaches will be smaller. 

Tasman Low - stage 2

The low will move SE during Tuesday and merge with a small trough in the central Northern Tasman Sea (which will be moving south), forming a broad band of SE gales that will settle off the SW tip of New Zealand’s South Island though Wednesday and Thursday. 

Whilst surf size may bottom out locally later Wednesday and early Thursday as the initial short range S’ly fetch eases and the SE fetch develops (say, peaky, lumpy leftover sets in the 3-4ft range at south facing beaches south of Byron, smaller elsewhere form this source), we’ll see a renewal of SE groundswell through Thursday afternoon back up into the 4-5ft range across Northern NSW (south of Byron) that could nudge 4-6ft into Good Friday. 

This swell direction once again won’t be great for SE Qld but we should see some decent surf from this source around 2-3ft across most outer points and open beaches by Friday (smaller on Thursday), with bigger sets at exposed northern ends approaching 4ft at times to finish off the working week. 

Tropical Cyclone Cook

While all of this is going on, Tropical Cyclone Cook will have crossed New Caledonia, reentered the lower Coral Sea under a SW track but then recurved to the SE, towards New Zealand. This cyclone looks really impressive with surface winds upwards of 85kts, however there are several limiting factors that will impact surf size for us.

Firstly, with no supporting high pressure ridge to the south, the fetch length will be short. In fact, the radius of 50kt+ winds around TC Cook is only modeled to be ~100km, so even under the most optimistic circumstances the actual fetch length aimed towards our region is likely to be only ~150km, if not less. By contrast, the Tasman Low is expected to display almost 1,000km of 30kt+ winds through the south-eastern Tasman Sea, with a width of 500km or more, aimed mainly towards Southern/Central NSW but also with a reasonable alignment towards Northern NSW.

Additionally, TC Cook is expected to track SE at a reasonable speed, which is perpendicular to the great circle path and will greatly reduce size prospects at the coast. 

Regardless, we should see a brief flush of E/NE thru’ NE swell building through Wednesday, peaking overnight and then easing through Thursday (expect a later build/ease cycle south from Coffs). Wave heights should reach somewhere between 3ft and maybe 5ft at reliable swell magnets at the height of the swell, and keep in mind that there’ll be a healthy mix of S’ly tending SE swell at the same time too. So, there could be some interesting swell combos at appropriate beaches (local winds pending). Expect this cyclone swell to be almost completely gone by Friday.

Local winds

The Tasman Low will dominate our region all week, driving fresh and gusty S’ly winds from Tuesday through Thursday (though initially SW in SE Qld on Tuesday). The southerly will ease back for Wednesday and this weaker pressure gradient should allow for periods of early SW winds in a few locations - but not all - however for the most part expect the wind to be out of the southern quadrant.

By Friday we should see the pressure gradient slacken off at the coast, delivering light offshore winds and sea breezes just about everywhere. 

This weekend (Apr 15 - 16)

Tasman Low - stage 3

A strong front pushing up the Southern NSW coast late Friday looks like it’ll be a pretty decent system, merging with the remnants of our mid-week Tasman Low in the southern Tasman Sea, restrengthening a broad S/SE fetch off Tasmania’s East Coast, building southerly swells into Southern NSW for Saturday, that will reach Northern NSW on Sunday. 

Also adding energy into this complex system will be ex-TC Cook, which is currently modelled to skirt southwards down New Zealand’s East Coast later this week, rounding the southern tip to the west and pushing back into the Tasman Sea, eventually merging in some way shape or form with the Tasman Low - quite a transformation if it comes off. 

Anyway, this combined fetch doesn’t look like it’ll be perfectly aimed within Northern NSW’s S'ly swell window, but early indications are for a peak over in the 4-5ft range at south facing beaches south of Byron on Sunday.

Prior to that - on Saturday - expect residual, easing SE swell, with early 3-5ft sets at south facing beaches (south of Byron) losing a foot or two during the day. 

Across SE Qld we can expect smaller surf from the SE this weekend, easing from 2-3ft at outer points and northern ends Saturday morning, becoming smaller into the afternoon. The new S’ly swell for Sunday won’t do much north of the border due to the swell direction.

Long Range E’ly groundswell

However, we have another swell source expected for the weekend - a small to moderate, very inconsistent long range E/NE swell generated by a subtropical low forming well NE of New Zealand - a little less intense than TC Cook but with a broad supporting E’ly fetch to the south thanks to a southern high pressure system, displaying an impressive fetch.

Unfortunately the enormous travel distance will shave off the majority of size from this swell but it should add a minor undercurrent of E’ly swell building into the 3-4ft range through Saturday, peaking Sunday. This should complement the building S’ly swell nicely (south of the border), but there will be very long breaks between sets. 

Next week (Apr 17 onwards)

Diminishing long range E’ly swell

The weekend’s inconsistent long range E’ly swell will ease through Monday though we should see occasional 3-4ft sets at exposed beaches to begin with (size will probably be a little smaller form Coffs south). 

Expect wave heights to taper off through Tuesday, and by Wednesday it’ll probably be all gone. Winds are expected to freshen from the NW on Monday and Tuesday as another cold front approaches from the west

Another Tasman Low?

Mode guidance is suggesting another cold outbreak across the SE part of the country for the early to middle part of next week which should result in another Tasman Low across our immediate southerly swell window, with subsequently solid S’ly swells to dominate the second half of next week. Let’s take a closer look on Wednesday.