Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 25th March)

Best Days: Fri: improving conditions with a combo of easing S'ly swell and building E'ly swell. Sat/Sun: light morning winds, peaky E'ly swell tending E/NE. 

Recap: A solid S’ly swell built across the coast on Tuesday, reaching 3-5ft at south facing beaches into the afternoon (and 4-6ft across the Hunter) before slowly easing from 4ft this morning. Early light winds on Tuesday preceded a moderate afternoon sea breeze, and this morning’s light winds have been replaced by a moderate to fresh S’ly change that reached the Northern Beaches just after 1pm.

This week (Mar 26 - 27)

The trailing fetch behind today's southerly change isn't anything amazing, but it’s loosely attached to a stronger low/front combo pushing through the lower Tasman Sea. It's not a perfect storm track by any means, but we’ll see a decent S’ly groundswell build on Thursday before easing Friday. From this source, surf size should rebuild back into the 3-4ft range at south facing beaches by the afternoon (and up to 4-5ft+ across the Hunter). 

However, there will be a few additional swell trains in the water too. 

We’ll see some small short-range energy from the fetch behind the current coastal wind change (nothing special, likely 3ft at south facing beaches) but more interesting is a potential long period swell that was generated in an acute region of our distant swell window earlier in the week, below Western Australia. 

It’s not viewed as a particularly reliable source but nevertheless, with core winds up over 50kts, we may see some larger peak swell period values at the wave buoys (modeled estimating a steady climb from 12.5 seconds to 14.8 seconds throughout the day, as per Northern Beaches data below) and this may translate to larger sets glancing a handful of reliable south swell magnets and offshore bombies. 

This is an extremely low confidence event but if we do see the odd sneaky 6ft+ set, this is where it would have originated from (timeline for this would be very late afternoon in Sydney/Newcastle - maybe even overnight or early Friday morning - but earlier south from the Illawarra). 

As it is, local conditions don’t look great on Thursday anyway.

A lingering moderate to fresh southerly flow will create bumpy lineups at most exposed beaches; chances for an early morning SW breeze are slim at best (maybe just the Northern Beaches if we’re lucky). Winds will ease throughout the day so there should be a gradual improvement though it’s not worth getting too excited about.

On Thursday, the southerly change will weaken into a broad trough across the central/northern Tasman Sea, and a building ridge of high pressure to the south will freshen an easterly flow across its southern flank. So, as southerly swells ease in size on Friday (still 3ft south facing beaches early, bigger on the Hunter), we’ll see a similar level of E’ly swell building through the day. 

Friday’s conditions look a little better, with generally light onshore winds, trending variable in some regions. The Hunter region may see lingering SE winds of moderate strength, so I’m not expecting anything great north of Sydney, but anywhere from Sydney to the south should be thoroughly workable. However without a synoptic offshore to clean things up, there’ll be a residual wobble through the lineup.

This weekend (Mar 28 - 29)

The latest model runs maintain the easterly fetch aimed within Southern NSW’s near swell window into the start of the weekend.

In fact, the trough is expected to push towards the coast (and broaden in latitudinal coverage) as a new ridge builds through the northern Tasman Sea. This will effectively swing the fetch to the E/NE and then NE over the weekend.

As a result we should see 2-3ft E’ly swell persisting through Saturday, along with some small residual S’ly swell.

The E’ly swell will ease a little into Sunday but we’ll also see a small spread of E/NE swell from the Tasman ridge at the same time. Sets should maintain 2ft, maybe 2-3ft if we’re lucky but south facing beaches will be smaller. 

Local conditions look reasonably good this weekend. Light variable winds are expected for much of Saturday and early Sunday under the coastal trough, but Sunday afternoon will see freshening NE winds. So, aim for an early session both days. 

As a side note, model guidance has a late Sunday arrival of small long period S’ly swell from a polar low below the continent this week (see below) but I’m not confident of any worthwhile size. 

Next week (Mar 30 onwards)

Looks like we’ve got mainly peripheral swell sources on tap for next week. 

At this stage the Tasman Sea is not expected to deliver anything worthwhile (a small low pushing NE from eastern Bass Strait on Monday has been downgraded), and our main source of energy will be sideband trade swell from the northern Tasman Sea ridge, and a couple of much larger but very distant systems in the South Pacific, well to the E/NE of New Zealand (see below). No major size is likely from either swell window.

Fleeting lows passing well south of Tasmania may also kick up minor southerly swells but it’s not looking like we’ll see much size at this stage.

However there’s been quite a few revisions in the model guidance over the last few days, so let’s check back in on Friday to see how things are looking.

See you Wednesday!