Looking back on a great run of surf

Craig Brokensha
Swellnet Analysis

Talking to surfers along the East Coast, the feeling is unanimous that it's been one the best starts to winter in years, and if we were to include May then the last six weeks has been the best run of surf in a very long while.

It hasn't been overly sizable, though a large swell in early May rearranged the banks across most of the NSW coast, and with sand flowing northward since February, filling up many of the northern pointbreaks, it's been a stellar run.

Morning offshores, weak afternoon sea breezes - if any at all - and hardly a day under 2ft.

On the other hand, Western Australia has been smashed by persistent mid-latitude storms with widespread erosion and limited clean surf days around the Margaret River region. Perth and Mandurah have pumped in between cold fronts while the southern states have seen smaller swells though generally favourable conditions.

Looking at the Mean Sea Level Pressure and Wind anomalies for the months of May and June, the reason for our great run of surf becomes obvious.

During May, northern NSW and south-east QLD saw persistent long-range swell energy from the east. This pattern is clear on the charts below.

Mean Sea Level Pressure and Wind anomaly for May

A strong high pressure anomaly (8hPa above average) is evident immediately east of New Zealand and the resultant winds were stronger than the long-term average by 7m/s. That being 25km/h or 13kts. The beauty of having this setup at arms length from the Australian continent is that we also saw favourable offshore breezes.

On the other side of the country though we can see the interaction of a low in the Southern Ocean and high across the Indian Ocean bringing onshore winds to WA's South West while generating westerly swells for South Australia and Victoria.

Into June, the high pressure anomaly east of New Zealand persisted and while it appears weaker than May, that's just the shift in colour scale and we saw an even stronger positive anomaly. The difference was a significant 13hPa above the long-term average (clearly visible on the higher-resolution Bureau of Meteorology charts), while what's interesting to point out is the low just west of New Zealand's North Island.

This setup allowed for more distant easterly trade-swell to filter in through most of June, while also generating swells from the east to south-east, originating from the eastern Tasman Sea, directly off New Zealand's western coasts.

Mean Sea Level Pressure (charts 1 & 2) and Wind anomaly (chart 3) for June

A slight low pressure anomaly is observed south-west of Western Australia but there's no major trend in the wind anomalies as this is the time when we see weather and wind patterns shift more onshore.

The coming month looks to remain active for the East Coast with a week and a half of southerly swell possibly followed by easterly energy. While over in WA there'll be less consistent days of larger, onshore surf.

In between there's nothing too significant shaping up for the southern states (away from a possible sizey west swell in South Australia mid-month), though conditions will remain favourable. These finer details will be discussed in the Forecaster Notes over the coming weeks.

Comments

freeride76's picture
freeride76's picture
freeride76 commented Thursday, 2 Jul 2020 at 1:36pm

Nice wrap Craig.

Trade swells on steroids I called it.

donweather's picture
donweather's picture
donweather commented Thursday, 2 Jul 2020 at 3:27pm

I called it summer in winter!!!

geek's picture
geek's picture
geek commented Thursday, 2 Jul 2020 at 4:41pm

Ignoring the temps it’s summer in winter in Vicco too, been unreal (except for those on the surf coast!)

tango's picture
tango's picture
tango commented Thursday, 2 Jul 2020 at 10:16pm

Yep, been shithouse here for weeks with no sign of improvement. No point coming down this side, much better on the peninsula.

Blowin's picture
Blowin's picture
Blowin commented Thursday, 2 Jul 2020 at 2:05pm

Those East swells are unreal.

Eugene Green's picture
Eugene Green's picture
Eugene Green commented Thursday, 2 Jul 2020 at 2:28pm

Sorry, are you saying WA will see less onshore days or more onshore days with less consistant swell?

Craig's picture
Craig's picture
Craig commented Thursday, 2 Jul 2020 at 2:31pm

Less onshore days. Ie not as many large, onshore days as you've seen.

Lottolonglong's picture
Lottolonglong's picture
Lottolonglong commented Thursday, 2 Jul 2020 at 3:37pm

This article really rubs salt in the wound after breaking two bones in my arm in April

Pngy's picture
Pngy's picture
Pngy commented Friday, 3 Jul 2020 at 4:33pm

Awesome wrap Craig - love seeing macro analysis like this.

Is there any truth to the notion of "dry winters" produce better surf for southern regions like Vic, SA and Margies? And if so, what are the metrics to track that indicate whether it's dry or not?

I imagine it's much more nuanced than this, but am wondering if there's any truth to the saying

sc1southern's picture
sc1southern's picture
sc1southern commented Saturday, 4 Jul 2020 at 8:35am

Far from being a dry winter here in metro SA. Been consistently wet and fairly certain our average rainfall is way up there. Swells have been ridiculously consistent and strong.

Logical's picture
Logical's picture
Logical commented Saturday, 4 Jul 2020 at 12:52pm

This winter and last summer have been in my opinion the worse in 40 years, of my surfing, on the east coast of Sydney at least.

All we get since perfection of 2010 to 2012, then the drought hit. 95% of swell is straight line south swell that refracts into long close out lines,

freeride76's picture
freeride76's picture
freeride76 commented Saturday, 4 Jul 2020 at 2:26pm

what happened to all the E through SE swells Logical?

Ray Shirlaw's picture
Ray Shirlaw's picture
Ray Shirlaw commented Saturday, 4 Jul 2020 at 10:36pm

Not nuanced at all Png, big cold fronts= lots of rain&totally shit SW winds