Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Fri 27th August)

Forecast Summary (tl;dr)

• Residual S swell Sat with a better angled S/SE pulse for the PM, good AM winds
• Better angled SSE swell holding Sun with excellent winds AM
• Long range, small, inconsistent E/NE swell in the mix from Thurs-Sat, overshadowed by dominant S/SE swell regime
• Easing SSE swell Mon/Tues maintains fun surf with good winds
• New ESE swell Wed, holding Thurs
• Dynamic outlook next week, E swell likely by next weekend, stay tuned for details

Recap

Our slow moving low in the lower Tasman Sea has maintained plenty of good to great surf since Wed’s f/cast. Solid 6-8ft swell from the S across most of the region, slowly eased back during the day. Conditions were clean in the morning with W’ly winds which then tended SW and S restricting clean options to more protected Bays where size was significantly smaller. 

Today size has eased back further but with still solid 5-6ft surf on offer there’s plenty of energy still in the water. Conditions were prime early with offshore winds, although a bit of leftover bump scarred surf in the Hunter from yesterdays S’ly winds. Lots of good options for experienced surfers with sheltered Bays suiting those needing a bit less size. Winds have gone a bit unruly, with a S’ly flow on the Illawarra, grading more SW further north of the Sydney Basin and straight W to WNW on the Hunter.

This weekend (Aug 28-29)

Not much change from Wednesday’s f/cast notes. Current ASCAT (satellite windspeed) passes show our Tasman low in a great place, slowly drifting E of Tasmania towards New Zealand, maintaining a nice pressure gradient squeeze with a high pressure cell SE of Tasmania. As expected, the low has filled in a bit, with a corresponding lessening of windspeeds, mostly low end gales, compared to the storm force winds of it’s “bombing” phase. 

Thus our next pulses, despite being from a better SSE angle, will be of a smaller order of magnitude. 

The weekend  still looks great, with a ton of surf. Synoptic winds from the low maintain offshore winds through Sat morning, so tick that box. Through the a’noon, they are likely to tend SW through S as the low begins a slow NE movement. I think we can still run with Wed’s size estimates. Smaller 3-4ft to begin with, grading 3-5ft at known swell magnets before a better angled pulse of SSE swell builds through the PM into the 4-5ft+ range. 

That pulse is expected to hold through Sun AM at similar size with a morning offshore flow that is likely to tend W/NW, then NW before an approaching warm front and trough sees winds tend NE to N and freshen. There’ll be some strength in that a’noon Nor-easter so you’ll need to factor it in if Sun PM is your window.

Next week (Aug 30) and beyond

What an incredibly dynamic synoptic set-up greets us to end winter and start Spring. The overall pattern looks more like a late Summer, early Autumn one, giving an indication that our atmosphere is being influenced by a La Nina signal.

To start lets rule out the southern swell window. A solid blocking pattern is expected with a “peanut” high straddling New Zealand next week, forcing the Southern Ocean storm track well to the south and with a NW fetch orientation. 

We’ll be in mop-up mode Mon and Tuesday with residual swell energy from the SSE slowly tailing off. Likely 3-4ft on Mon, dropping back into the 2-3ft range Tuesday and 2ft by close of play. Conditions should be excellent with a weak low drifting off the coast Mon, bringing a synoptic W’ly flow and light seabreezes in the a’noon.

Remnants of this weeks Tasman low are expected to drift NE towards the North Island over the weekend and reintensify Sun/Mon with a fetch of severe gales extending out of Cook Strait into the Tasman Sea. These fetches typically favour Central NSW for most size with a resultant ESE swell direction. There has been some model variance on the strength of the fetch but based on current modelling we’re looking at surf building Wed PM into the 3ft range, with a chance of some stray 4ft sets. That number could get an upgrade if windspeeds ramp up as they tend to do from those Cook Strait fetches.

This pulse holds into Thursday AM at similar size with high pressure drifting over the area bringing a regime of light land and seabreezes.

An extended E’ly pattern then sets up, as high pressure straddles New Zealand and the troughy remnants of the Tasman low squeeze pressure gradients along a long, broad fetch extending through the South Pacific adjacent to the North Island and extending into the Coral Sea. Models show this fetch then further retrograding back towards the Australian East Coast to end the working week.  While we’ll need to come back in on Mon to dial in specifics we’re looking at an increase in E’ly swell across most of the Eastern Seaboard possibly as early as next Fri, but certainly through next weekend and into the week starting 6/9. Winds look tricky with a potential small coastal trough bringing a wind change next weekend. Size looks to be in the 3-5ft range but we’ll revise this on Mon. 

Have a great weekend and hope you are scoring some surf.