South-east Queensland and Northern NSW Surf Forecast by Ben Matson (issued Mon Mar 11th)

Features of the Forecast (tl;dr)

• Strong trade swell through Tues/Wed, easing Thurs onwards
• Mod/fresh SE winds Tues/Wed north from Ballina, light var + sea breezes across the MNC
• Small south swell for Northern NSW on Thurs, easing Fri
• Resumption of fresh SE winds for the weekend with a building trade swell, though more S/SE tending SE in direction at first
• Secondary S and S/SE swells in the mix this weekend (mainly Northern NSW)
• Stacks of trade swell for next week
• Plenty of S and SE groundswell sources for next week too

Recap

Building trade swells over the weekend increased from 3-4ft to 5-6ft, and are now showing strong sets to 6-8ft+ across some exposed parts of Northern NSW (tho' smaller elsewhere), with great waves on offer across the regional points. It's been very windy out of the SE quadrant too.

The Coolangatta machine in action late Monday

This week (Mar 12 - 15)

Our current swell event is a byproduct of a strong trade flow through the Northern Tasman and lower Coral Sea, extending back into the South Pacific. 

A broad Tasman high is experiencing a tight squeeze with several low pressure centres around New Caledonia and Vanuatu enhancing wind speeds and supercharging what's already an active sea state, thanks to the stationary fetch. One of those lows will track towards the Capricornia Coast mid-week.

And, this means there's no real change for conditions over the next few days. Theoretically the models are suggesting a little more size into Tuesday and Wednesday (as swell periods nudge up another second or two) however I don't think we'll see much bigger surf across Northern NSW - which is already in the 6-8ft+ range - rather, we'll see a broader spread of the upper end of this size range into nearby regions, which have seen comparatively smaller surf. 

In any case, locations north from about Ballina will see winds remaining moderate SE for the next few days, so conditions will only be only suitable for points and sheltered spots. Exposed beaches will remain maxed out for much of the week (note: winds south of Ballina will be light and variable with sea breezes until Friday).

Size? Broad brushstrokes are fine for an event like this, as the trend will be very slow moving and the reach of this swell will be almost everywhere in some shape or form. Let's peg most open stretches in and around the 6-8ft+ mark (smaller on the points), with smaller surf south from Yamba. 

Size will ease throughout Thursday though not by much, possibly down to 3-4ft by Friday afternoon across SE Qld and Far Northern NSW, and 2-3ft around the Mid North Coast.

For the record, a small south swell will push up the Northern NSW coast on Thursday (easing Friday) but it won't be discernible beneath the E'ly swell. 

A gusty southerly change is expected to push along the coast on Friday afternoon too.

This weekend (Mar 16 - 17)

A new ridge will become established across the region for the weekend which means a return to fresh SE winds, and points-only surf conditions.

And, it's looking like another long run of trade swell from Saturday right through into the following week.

Initially, Saturday's building swell will be more S/SE tending SE which will affect size potential across the regional points (compared to the current event, which is E'ly) so keep this in mind - exposed beaches will be much bigger though also quite wind affected.

Let's put wave heights building from 2-3ft to 3-5ft across the SE Qld and Northern NSW points from Saturday into Sunday (maxing out around 4-6ft at exposed beaches), with slightly smaller surf south from Yamba - though there'll also be a decent southerly swell in the mix south from Byron, originating from a strong front pushing up into the lower Tasman Sea late Thursday and into Friday.

Late Sunday may also see (mainly across the Mid North Coast) some longer period S/SE energy from a stationary polar low well south of New Zealand on Wed/Thurs this week

Let's firm up the specifics on Wednesday, as surf potential will really hinge around the winds.

Next week (Mar 18 onwards)

There's a lot to look forward to next week, with several interesting swell sources on the boil.

First up - the trade flow should maintain strong E'ly swells across most regions all of next week. Probably not as much size as what we've seen this week, however another passage tropical lows - one of which may develop into a tropical cyclone - will keep the outlook interesting for some time. It's a classic autumn pattern for the East Coast.

Elsewhere, and strong though poorly aligned fronts through the Southern Ocean and lower Tasman will supply small background south swells for Northern NSW throughout the first half of the week, maybe longer. 

Probably the most interesting swell sources is a deep, slow moving polar low well to the SE of New Zealand this Sunday (see below) that looks like supplying some rare long period SE groundswell to Northern NSW later Thursday and Friday. These swells often over-perform so I'm quietly confident that this could deliver some nice waves (local winds pending, of course).

More on that in Wednesday's update.