Complex period ahead, with a pocket of fun weekend waves

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 12th March)

Features of the Forecast (tl;dr)

  • Easing winds early Sat, building NE swell
  • Wind affected combo of easing NE swell and building S'ly swells Sun, with gusty S'ly winds
  • Easing surf Mon/Tues, prob still wind affected
  • Potentially strong surf Wed/Thurs from a redeveloping low near the NSW coast
  • Inconsistent S'ly groundswell Wed though local conditions unsure

Recap: Average surf for the last few days with a small south-east swell providing 1-2ft waves in Sydney, and rare 2-3ft sets in Newcastle, followed by a building NE windswell today but with accompanying NE winds. Really nothing to get terribly excited about.

This weekend (Mar 13 - 14)

We’ve got a synoptic pattern reminiscent of spring at the moment, with a high in the eastern Tasman, a deepening inland trough and an approaching change to the west all combining to muscle up a NE flow against the NSW coast. 

Although this fetch will reach peak strength early Saturday, it will occur as it slowly rotates anti-clockwise outside of our swell window. As such, we may end up seeing a peak in size through Saturday morning (rather than the afternoon), along with a chance for a chance for a pocket of early light N/NW winds, preceding a refreshening N/NE flow throughout the day. 

As for size, wave heights should reach 3ft, maybe 3-4ft at reliable NE swell magnets (smaller at south facing beaches and across the Hunter) though the longer fetch length relative to the South Coast could see slightly bigger waves south from the Illawarra.

Model guidance also has a minor long period S'ly swell in the mix on Saturday too, but as I'm time-limited (to hindcast the source) I'm really not able to verify whether it'll translate to any notable size (having originated from a very distant source, and based on today's size throughout Victoria and Tasmania, chances are slim though). 

The local NE swell will gradually ease through Sunday, but it’ll be overtaken by a windy, local south swell accompanied by developing southerly gales as the trough moves offshore. South facing beaches should increase to 3-5ft by the afternoon but quality will be in low supply and it’ll be much smaller at those few locations offshore shelter from this wind direction.

Next week (Mar 15 onwards)

The outlook for next week is very dynamic, but the short story is that there’s likely to be plenty of swell - and probably wind - on the way.

Sunday’s trough will push north overnight and probably form a closed low off the Mid North Coast by Monday morning, reasonably close to the coast. At this stage model guidance is in pretty good agreement that it’ll meander throughout the western half of the Tasman Sea for a few days, potentially retreating back to the south, i.e. closer to our local swell window. It could also end up becoming an East Coast Low but it's too early to be sure. 

Right now the models are not really picking up the finer details of this scenario very well (with regards to surf size potential) which is not altogether unexpected, thanks to the complex atmospheric dynamics and its proximity to the mainland. However, it’s worth stating that I think they’re undercalling things at the moment - expecting just a couple of feet through the week - when in actual fact there’s potential for a sizeable swell out of the eastern quadrant mid-late week. 

Of course this is highly dependent on the actual strength and position of the low, which won’t really become clear for a few more days. But, I’d be ready for some solid surf next week as the regional atmosphere is somewhat primed for explosive development right now.

Regardless, for now I’m thinking the first half of the week has the potential to remain wind affected (with gradually easing S’ly swells from Sunday), ahead of a rebuilding trend around Wednesday that should hold until Friday. I really don’t want to pin down size estimates right now - as the models will invariably change focus, approximately seventeen minutes after I press ‘publish’ - but somewhere in the 4-6ft range seems plausible somewhere in NSW from the rebuilding trend (for what its worth, the European solution suggests a lot more size than that right now). But whether that's Northern NSW or Southern NSW remains to be seen.

Also, a strong Southern Ocean low passing underneath Tasmania on Sunday and Monday will also provide a decent pulse of southerly groundswell, later Tuesday (South Coast) and Wednesday (elsewhere), that should push an inconsistent 4-5ft at south facing beaches. Hopefully local winds won't spoil this swell though.

Anyway, James will get you back up to speed on Monday - fingers crossed for some fun waves Saturday, and then a positive outlook for the second half of next week. 

Have a great weekend!


science's picture
science's picture
science Friday, 12 Mar 2021 at 8:14pm

water was a lot colder this arvo in newy

NDC's picture
NDC's picture
NDC Friday, 12 Mar 2021 at 10:04pm

Great notes ben. Thks

belly's picture
belly's picture
belly Saturday, 13 Mar 2021 at 9:29am

SE ABC radio saying shark attack at Merimbula, victim air lifted, beaches closed.

sean killen's picture
sean killen's picture
sean killen Saturday, 13 Mar 2021 at 10:07am

There was heaps of fish jumping around yesterday/today .. definitely very active at the moment.. hopefully ol mate is ok down the south coast