Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 17th April)

Best Days: Mon/Tues/Wed/Thurs: large to very large SE swells but windy as an ECL intensifies off the coast.

Recap: Plenty of good quality leftover surf on Thursday with generally clean conditions for most of the day, but there was very little on offer today with winds tending light to moderate onshore. 

This weekend (Apr 18 - 20)

The weekend’s looking pretty average on the whole. 

With no new swells in the water for Saturday, the only chance for a rideable wave will be sourced off a freshening northerly breeze during the day. If anything develops it’ll be small and low quality - exposed NE facing beaches may see poor quality 1-1.5ft waves through the afternoon but it’s not worth working around.

The dynamics of Sunday’s expected southerly change have been pushed around a little in the latest model runs. We’ll see an initial moderate SW change during the morning (NW winds across Sydney/Hunter beaches at dawn, but the sou'wester should be into the Illawarra fairly early).

However the core fetch expected to generate the first round of short range southerly swell isn't really expected to develop off the southern NSW coast until the middle of the day. As such the chances for a sizeable increase before dusk have diminished, but we should still see a late upwards trend, following a gusty southerly wind developing from about early-mid afternoon onwards. 

What this means is that I’m less confident that protected southern corners will have anything worthwhile by the end of the day - it may not be quite big enough. There should be sizeable, bumpy waves at exposed south facing beaches (maybe some 4-5ft+ sets on dark), so hopefully you can find a compromise between size and quality at remaining open beaches, in the 2-3ft range. 

If the model guidance changes notably before Sunday morning I’ll update the expected timing of the upwards trend in the comments below. 

Next week (Apr 21 onwards)

As discussed all of last week, we’ve got a proper East Coast Low developing early next week, in the wake of Sunday’s southerly change. 

Prior to its development (or during the early stages of cyclogenesis), gale force SE winds will envelop the southern NSW coast, probably from Monday onwards, and we’ll see a very large short range swell build across the region - likely into the 6-8ft range at exposed south facing beaches by the afternoon. Only protected southern corners will have anything worthwhile though.

As the low deepens and moves closer to the Sydney/Illawarra coast (from a position further north-east), it’ll strengthen SE winds about its core, aimed across the broader southern NSW region. Right now it’s hard to be totally confident on the timing of this development but the most likely scenario is for a steady increase from 6-8ft early Tuesday up towards 10-12ft+ at exposed spots through Wednesday and possibly early Thursday (it’s worth nothing that the 18Z run of our surf model is calling 15-18ft surf Wednesday evening! I haven’t seen this before). Obviously, protected spots will be a lot smaller too.

However, this very large swell swell event will be accompanied with persistent SE gales, so conditions are not likely to be friendly for most surf spots. In fact this swell event will be well worth considering some of the more sheltered nooks and crannies, for a novelty wave.

Additionally - and without wanting to sit on the fence - whilst the models are in broad agreement that we’ll see an ECL develop off the coast, they differ in their outlook on the structure of the low. There is a suggestion that we could see a more straight S'ly or even SW flow at times across parts of the region, but as this scenario is still four or five days away we need more time to assess the model data. ECLs are notoriously complex and it’s common for local winds to defy model guidance. 

In short, expect a lot of large surf, a lot of wind and a lot of rain right through next week. Conditions should then settle right across the board from Thursday onwards.

I’ll update my thoughts on any model deviations in the comments below over the weekend. Otherwise, see you Monday!