Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Fri 30th Sep)

Forecast Summary (tl;dr)

• Strong S’ly swell Fri as low deepens off Sydney with fresh S-SE winds
• Strong SE swell Sat with continuing S-SE winds (easing during the a’noon)
• Lighter winds Sun AM with still strong but easing SE swell
• Nice pulse of ESE swell Mon with light winds, slowly easing through Tues with morning offshores
• Possible strong SSE swell Wed-Fri 
• Pulses of S’ly groundswell likely from Wed next week
• Likely NE windswell from Fri next week as new inland low approaches
• Monitoring a few swell sources later next week, check back Fri for updates

Recap

A brief window of early cleaner conditions was erased yesterday by strong S’lies which saw short range S swell build into the 3ft range, bigger 4ft on the Hunter. That swell has continued to build overnight as a low winds up NE of Sydney with an unruly 4-6ft of S swell today, bigger 6ft+ on the Hunter. Not many clean options with strong S-SE winds along the coast. Even protected locations are looking a bit wind affected. That theme will continue across the weekend. Details below. 

Chunky, raggedy swell as low drifts offshore

This weekend (Oct 1-2)

No great change to the weekend f/cast. Wind and swell regimens  will be dominated by the low in the Tasman, which is now retreating towards the North Island with a large (1037hPa) high south of Tasmania. Pressure gradients do slowly ease over the weekend as the high relaxes over warm Tasman sea waters and the low sets up near the North Island. 

Still plenty of wind and swell for Sat morning. Expect mod/fresh S’lies with a a very brief window of lighter inshore SW winds confined to north of the Harbour before winds clock more SSE to SE. Size in the 5-6ft range, bigger 6-8ft on the Hunter with easing trend through the day. Through the a’noon we’ll see a noticeable easing in windspeeds as the pressure gradient along the coast relaxes with protected spots cleaning up and potentially looking pretty fun as swell direction clocks around a little more SE.

Swell continues to ease through Sun as the main Tasman Sea fetch fades away. Lighter S’lies are on the menu, likely SW on the South Coast and north of the Harbour, although residual S’ly sea state will likely leave some bump and lump to deal with. Mid period SE swell in the 4-5ft range will slowly back down further through the day. There should be a few more options Sun, especially if you are prepared to drive for cleaner conditions.

Next week (Oct 3 onwards)

High pressure starts to drift over NSW on Mon leading to excellent winds. Light offshore mornings and weak sea breezes through Mon and Tues.  The Tasman low sets up a fetch out of Cook Strait and extending from the West Coast of the North Island  over Sat/Sun so we’re still on track to get a nice pulse of SE-ESE swell through Mon. Expect size to build through the morning into the 4-5ft range, slowly winding back through the a’noon under light E’ly breezes.

Clean leftovers in the 3ft range Tues morning ease back to inconsistent 2-3ft sets through the a’noon. Light winds all day should make for some great beachies.

From Wed things start to look juicy again, although there is a fair spread in model guidance so it’s likely we’ll see significant revisions when we come back Mon.

The basic pattern is another strong high moving at a very southerly latitude, this time with strong frontal activity ahead of it. The fronts are expected to supply pulses of long period S swell from mid next week (see below). 

The front and leading edge of the high then generate a strong S/SE surge into the Tasman, tracking NE towards Tasmania (see below). That fetch is likely to see mod/strong levels of SSE swell Wed-Fri, although the southwards position of the high will see more onshore winds with the swell. 

Once the high moves out into the Tasman an approaching cut-off low tightens the pressure gradient and we see a N’ly fetch off the NSW Coast. We’ll be watching for NE windswell late next week. Models are really flip-flopping on this outcome so make sure you check back Mon for updates.

Finally,  we’ll be watching a developing broad tradewind flow through the South Pacific slot later next week. Although this fetch is better aimed at sub-tropical targets it may be broad enough and persistent enough to generate some useful E/NE tradewind swell for temperate NSW early in the week 10/10.

Lots of action to keep track of so check back Mon for the latest, and have a great weekend!