Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 3rd December)

Best Days: All days should have windows of fun NE surf in and around the thunderstorms. 

Recap: Lots of short range NE swell over the last few days, up to 3-4ft Tuesday and 2-3ft today with brief periods of variable/offshore winds in and amongst the overall NE trend. And some bloody good thunderstorms to boot! (including most of this afternoon, hence why the forecast is late).

This week (Dec 4th-5th)

Really, there’s very little change for the rest of the working week. We’re stuck in this troughy pattern for quite some time and its NE infeed across the western Tasman Sea will continue to supply us with small peaky short range NE windswell for the foreseeable future. 

Wind wise, we’ve got a mixed bag for the rest of the week. Another microscale low (similar to the one that delivered three hours of southerly winds overnight Tuesday) is modelled to form off the South Coast overnight Thursday, pushing along the southern NSW before dissipating across the Sydney region early Friday.

We’ll see freshening NE winds throughout Thursday - although the morning may offer light variable winds, especially south of Wollongong - and early Friday morning is likely to see a lingering southerly in most, but not all regions ahead of a variable trend thru’ lunchtime and then a renewal of nor’easters mid-late afternoon.

Let’s just call it variable then, eh?

Surf size will probably hold out in the 2-3ft range at NE facing beaches both days, but it looks like Thursday may have a smidge more size than Friday as the primary fetch is expected to retreat slowly eastwards as the southerly pushes up the coast.

I can’t see the southerly change providing much in the way of new swell though, so expect very small surf at south facing beaches. Either way there’ll be plenty of surfable waves at remaining exposed beaches.

This weekend (Dec 6th-7th)

This troughy pattern is one of the the more complex setups I’ve seen in a long time. The models are holding steady with the overall synoptic trend but still struggling a little with the finer points of the associated fetches, which - under these setups - are quite important. They are: proximity to the mainland, maximum strength, and overall alignment within our swell window. Small changes in any of these parameters can drastically alter the prospects of good waves.

Right now, the most likely trend for the weekend is a continuation of these ‘variable’ wind patterns along the coastal margine, although locations south of about Ulladulla may see freshening SE winds as the trough starts to take shape further into the Tasman. 

Although the main NE fetch feeding into the trough may hang some distance back from the mainland, it will have been positioned off the Mid North Coast for quite a few days (by the time the weekend rolls around) so it’s likely that our near swell window may have reached a condition known as “fully developed”.

Now, this is a very fancy sounding term - and normally I wouldn’t reference it unless it were a more impressive swell generating system - but it’s worth mentioning because it can often nudge up the potential swell heights from an otherwise ordinary fetch. It essentially means the maximum ocean wave heights produced by a given fetch of particular strength and size. In this case it means I'm going to bump up our model forecast from 1-2ft to 2-3ft.

On top of that, we’re looking at a small E/NE swell arriving on Sunday, originating from a developing band of trades in the Northern Tasman. This won't be terribly big but should provide some small useful energy into the mix.

For now, let’s ballpark wave heights in the 2-3ft range at most open beaches both days, but I’ll take a closer look on Friday as local winds will again be the key to scoring good waves.

Long term (Dec 8th onwards)

Looks like we can expect a similar outlook through next week as what we’ve seen this week; that is, an unstable troughy pattern with mainly short range NE swells and lotsa thunderstorms.