Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 15th January)

Best Days: Small mix of swells and generally OK winds Thurs. Slightly bigger mix of swells Sat, easing a little Sun, with tricky winds though it'll be workable. Complex mix of swells early next week with generally good conditions. 

Recap: So, Monday’s hunch that there was ’still some energy left in the tank’ for Tuesday was right, though my forecast (3ft+ south facing beaches, 4-5ft Hunter) was a little too conservative, with surf size generally coming in around a foot or more higher. Conditions were clean with light winds, and we’ve seen easing S’ly swells from 3ft south facing beaches today (bigger across the Hunter). Winds have again been generally light and variable (morning offshore, afternoon onshore).

This week (Jan 16 - 17)

An inland trough over the eastern states and a small Tasman high will direct N/NE winds across Southern NSW on Thursday. However, the pressure gradient is rather weak so there won’t be much strength in it. 

Thursday’s waves will consist of small easing S’ly swell, and some minor E/NE trade swell plus a trickle of NE windswell from the local fetch. Exposed beaches should pick up 2ft sets but it won’t be anything amazing. 

On Friday, winds will freshen from the south as the trough moves eastwards into the Tasman Sea (in fact, the South Coast will see this change on Thursday afternoon). Locations north of Sydney may see a brief window of light winds around dawn but it won’t be long until the change is entrenched across all Southern NSW coasts. 

As such, these winds will deteriorate surface conditions, and with similarly small swells as per Thursday, it’s not worth getting too excited. A small S’ly windswell will build in the wake of the change (2-3ft south facing beaches) but quality will be low at these locations. 

As a side note, both days may see occasional long period southerly sets from a distant polar low below South Australia on Monday. In general, most beaches will miss out but a handful of south swell magnets (i.e. the Hunter) may pick up occasional bigger sets than that mentioned above. It’s a low percentage swell though, and definitely not worth putting any time or effort into.

This weekend (Jan 18 - 19)

Persistent troughiness adjacent the Southern NSW coast creates a somewhat uncertain weekend waves. However, with flukey swell sources on tap it's a lttle too early to book anything into the diary.

We’ll see a continuation of small trade swell, and the N/NE fetch off the Mid North Coast will maintain position (even though it’ll ease temporarily Friday) so we’ll see peaky waves from this direction too. 

Additionally, strong southerly winds at the bottom of the trough responsible for Friday’s change - extending from Tasmania's East Coast - will generate some reasonable southerly swell for Saturday, probably the largest swell train in the water with sets around 3ft+ at south facing beaches, maybe a touch bigger if we’re really lucky.

Local winds are very difficult to have confidence in right now. For example, some of the latest model guidance is suggesting a small closed low will develop just east from Sydney on Saturday, which would result in S/SE winds on the South Coast, S’ly winds across the Illawarra and Sydney basin, then SW winds from the Northern Beaches to the Central Coast, and W’ly winds throughout Newcastle.

Of course, this is likely to change over the coming days but it highlights the difficulties in estimating what surf conditions might be like on the weekend. 

If anything, the broader trend suggests Sunday will see a better day of winds as the trough clears to the east, probably resulting in light winds through the morning though freshening NE breezes are likely into the afternoon. 

There’s also the chance for an upgrade in short range swell from the local N/NE fetch too, but I’ll have a better understanding of that in Friday’s update. 

Next week (Jan 20 onwards)

The large cyclone developing near Fiji at the moment looks quite impressive on the synoptics, but when you analyse the surface wind field, it’s a little more disappointing (see below) - the strongest winds are on its western and eastern flanks, aimed towards Vanuatu and New Zealand respectively. It's also expected to track at a reasonable pace southwards through the window, which is not ideal (though won't completely preclude swell generation for us).

We will pick up some useful E/NE trade swell from this system early next week (from the supporting ridge to the south, so technically not ‘cyclone swell’), but at this stage I’d be surprised if there was more than 3ft+ at exposed beaches. There is a chance for an upgrade though, as surface winds around the cyclone are very impressive and it'll only take a minor realignment to significantly increase our size prospects.

In addition to this, the troughy pattern lying across the coast will strengthen the local N/NE fetch and we’ll see building windswells early in the week too, probably of a similar size from the E/NE ridge swell associated with the cyclone. 

As for local winds, we’re looking at mainly variable conditions Monday ahead of a fresh W’ly change Tuesday, but there is a risk of a N’ly incursion at times on Monday, mainly from Sydney through to the Hunter (much less chance south from Sydney).

These two regions are our primary swell sources for next week, and at this stage there’s not a whole lot of new swell on the cards for the second half of the week, probably just easing size from whatever eventuates Mon/Tues. Let’s see what Friday’s model upgrades bring!