Sydney Hunter Illawarra Surf Forecast by Ben Matson (issued Wed 26th Apr)

Forecast Summary (tl;dr)

• Fun mix of swells this weekend but with tricky winds, esp south from Sydney
• Strong E'ly swell Mon, easing slowly from Tues, gen good winds
• Fun small south swells mid-late next week

Recap

Average, easing surf for the last few days with lumpy conditions. Size around the 2-3ft mark, being a mix of east swells and a trace of southerly energy.

This weekend (Apr 29 - 30)

Waves won't be an issue this week, with building E/NE swells from the low developing in the northern Tasman. Size should reach 3-4ft at exposed beaches though there may be a brief lag on the upwards trend early Saturday.  We should also see some peaky NE windswell from the fetch muscling up adjacent the coast today. 

However, local winds are an issue thanks to a develop low just off the Southern NSW coast on Saturday. This is expected to generate southerly gales about its westerm flank, but the most important point of information for surfers will be the position of the low's axis.

North of the low, winds will outflow from the W/SW, of moderate to fresh strength. So, the surf will be nice and clean across these regions with great conditions. However, close to the low, winds will tend more SW and strength, and then south of the low we'll see S/SW tending S'ly winds at strength, creating much more difficult conditions and reduced surfable options.

So, where will the low be positioned this weekend?

On Saturday, the southerly flow looks like it'll extend northwards into the Ulladulla region as the low develops through the morning, and may possibly nose into the Illawarra into the afternoon. North from here - i.e. Sydney and Newcastle regions - we'll see overnight N'ly winds tending light NW through the morning and thus clean conditions. 

Anywhere in the middle could swing either way. 

Overnight Saturday and into Sunday, it looks like the low wil intensify off the Sydney/Illawarra region, bringing the southerly fetch a little further north, probably to about the CBD or thereabouts. This suggests locations north of the harbour through the Cenny Coast and Hunter could see favourable early conditions though it's not a sure bet. South of the harbour, it looks quite blustery from the S/SW thru' S though isolated pockets of early SW winds can't be ruled out.

The low is then expected to slowly retreat southwards through the day, spreading the region of favourable conditions south from the northern Beaches into the Illawarra later in the day. 

The low should also generate some short range south swell through the weekend, initially the South Coast on Saturday but spreading north into remaining regions on Sunday. I'm not confident on size from this source as the models vary in the width of the associated fetch, but 3-4ft sets (in addition to the east swell) are possible at south facing beaches. 

So on the balance, keep your expectations low south of Sydney but to the north we should see some nice waves both days (Sunday's conditions being lower confidence than Saturday).

Next week (Apr 31 onwards) 

Model guidance is all over the shop for early next week, with regards to local winds. This is because they can't make up their mind how the weekend's easing low will interact with an approaching front from the west. 

Fortunately, either solution look good for surf with winds likely to be some kind of offshore from the W/SW quadrant, it's just a matter of how strong. But, let's keep this outlook a little flexible for the next few days while the synoptics evolve. In particular the South Coast will remain at risk of gusty SW thru/ S/SW winds for a period.

Otherwise, surf potential is great with the current low pressure system in the northern Tasman Sea (see below) intensifying into the weekend to generate a strong round of E/NE swell that will build to a peak on Monday, anywhere from 4-5ft at most open beaches, pushing 6ft at the swell magnets. Size will then slowly ease from Tuesday.

The long term has easing E'ly swell through the back half of next week ahead of a small trade swell the following weekend, and a series of south swells filling in the middle to latter part of next week, sourced from a mobile frontal progression across the Tasmanian region. Nothing amazing but certainly more than enough to keep the coast active.

Have a great weekend!