2020 vision: The surf outlook for the next three months

Craig Brokensha
Swellnet Analysis

Key points

  • The next three months are very different compared to this time last year
  • La Niña is developing
  • Increased easterly swell for NSW and QLD, and more cyclones
  • Favourable winds for the points and bays of N NSW and QLD
  • Blocking pattern for Victoria and southern Tasmania
  • Less long-period swell for Western Australia

As a keen weather watcher, a lot has come to pass since this time last year.

Hot off the back of one of the strongest positive Indian Ocean Dipole (IOD) events on record (with large cold water anomalies sitting off Indonesia and warm water piled up towards Africa), last September the global circulation pattern was disrupted to such an extent it reverberated into the upper atmosphere, causing a Sudden Stratospheric Warming (SSW) event over Antarctica.

This SSW - only the second significant event recorded in the Southern Hemisphere - then flowed back down through the lower atmosphere a month or two later. It caused a shift in the weather patterns across Australia and New Zealand through the second half of spring and into summer while also preventing the northern monsoon from properly developing.

A northerly shift in the westerly storm track (when it's usually contracting south towards the South Pole) brought dry westerly winds and record breaking heat, and in turn the worst bushfire season on record.

In terms of surf, the lower than normal pressure south of Tasmania generated fun swells and unseasonally clean conditions for the Victorian Surf Coast under the north-westerly winds, while these ruined what usually is the best time of year on the Mornington Peninsula.

Last October/November/December's Mean Sea Level Pressure Anomaly

At the same time, northerly winds plagued the south-east Queensland and northern NSW regions, while Sydney saw unseasonal westerly winds, clean conditions, and fun pulses of diffracted southerly swell.

Jumping ahead to this spring and we're seeing a developing La Niña starting to reach the thresholds needed for it to be official, and the opposite setup looks to be present for the coming few months.

What we know from La Niña is that the East Coast sees an increase in swell activity from the eastern quadrant, linked to instability in the Coral Sea from the build up of warmer water in the Western Pacific. This also results in more cyclones, but as we've discussed many times in previous articles on Swellnet, cyclones don't always produce the best swells. For that to happen, a cyclone must be cradled by a strong supporting high pressure ridge, which is discussed in more detail here.

The UK Met Office has just released its seasonal forecast for the coming three months (October, November and December) and what it shows that we'll likely see higher than normal pressure sitting just south of the Tasman Sea, extending just west of Tasmania and strongest just south-east of New Zealand.

UK Met Office Mean Sea Level Pressure forecast for October/November/December

Above this in the Coral Sea, lower than normal pressure is expected, linked to the developing La Niña.

There's also a slight indentation (lighter blue) on the forecasts across NSW and south-east Queensland, indicating a wind regime more from the east to south-east across these regions (not northerly), favouring the Gold Coast points and other protected bays.

With the higher than normal pressure extending under Tasmania and into Victoria's swell window, instead of the fun run of swell and westerly winds seen last year, we'll see more of a blocking pattern, hence less swell activity compared to normal and winds out of the eastern quadrant, favouring the Mornington Peninsula and Phillip Island.

If you live on the Apple Isle, focus your attention to the East Coast, with swells more likely from the north-eastern quadrant. The South Arm will be quieter owing to the blocking pattern.

Western Australia is tricky, with a continuation of mid-latitude systems more than likely, combined with a decrease in larger, long-range energy owing to a forecast increase in pressure across the south-western Indian Ocean, the main swell generating region. This will flow on to South Australia with less swell out of the south and more energy from the west.

As always, keep updated with the specifics for each region by subscribing to the thrice-weekly Forecaster Notes.

Comments

geek's picture
geek's picture
geek commented Tuesday, 29 Sep 2020 at 4:03pm

Thanks Craig. About time the MP had a win!

Craig's picture
Craig's picture
Craig commented Tuesday, 29 Sep 2020 at 4:05pm

And, it's official!

mibs-oner's picture
mibs-oner's picture
mibs-oner commented Wednesday, 30 Sep 2020 at 4:46am

Waiting for you to go first

kevin.brown's picture
kevin.brown's picture
kevin.brown commented Wednesday, 30 Sep 2020 at 3:59pm

More great whites up west coast with stopping of leuwin current from abrollis islands and flow of colder water pushing up from southern ocean and pushing bait fish closer to shore bringing bigger fish closer and flowing on to big whites n lots of em

Polly2's picture
Polly2's picture
Polly2 commented Monday, 5 Oct 2020 at 2:58pm

So would this mean possibly a funish summer on the mid with more of a westerly source than south? Or more so on land than in the G.A.Bight ? From memory the last La Niña we had an awesome Christmas boxing day swells and a really good summer of waves. Or was that el Nina ?

Ajp

Solitude's picture
Solitude's picture
Solitude commented Tuesday, 29 Sep 2020 at 4:17pm

Looks like an already cracking year is set to continue. Anything from the east without N winds during spring is a win in my book.

Nick Bone's picture
Nick Bone's picture
Nick Bone commented Tuesday, 29 Sep 2020 at 5:29pm

So favourable winds but probably on the smaller size in swells I take it for East Coast Vic?

I am the bone

Craig's picture
Craig's picture
Craig commented Tuesday, 29 Sep 2020 at 5:46pm

Looks so.

truebluebasher's picture
truebluebasher's picture
truebluebasher commented Tuesday, 29 Sep 2020 at 5:31pm

Yep! Good snoopin' Craig!
My TV just said the same thing...must be true!

velocityjohnno's picture
velocityjohnno's picture
velocityjohnno commented Tuesday, 29 Sep 2020 at 5:59pm

so more ordinariness for the Surf Coast, it's enough to make you break into song:

(Go East) Life is peaceful there
(Go East) In the open air
(Go East) Where the skies are blue
(Go East) This is what we're gonna do

Spuddups's picture
Spuddups's picture
Spuddups commented Wednesday, 30 Sep 2020 at 5:37am

That’s a real foot tapper.

dazzler's picture
dazzler's picture
dazzler commented Tuesday, 29 Sep 2020 at 7:19pm

What do you reckon it will do to wet season / moonson in Indo? Last year the wet was very late & water was in short supply. Asking for a friend...

Craig's picture
Craig's picture
Craig commented Tuesday, 29 Sep 2020 at 7:33pm

Last year was massively delayed and near non-existent due to the strong + IOD event.

This year we've got a weak -IOD event, and this linked with La Niña should see an earlier wet season and likely wetter than normal..

dazzler's picture
dazzler's picture
dazzler commented Tuesday, 29 Sep 2020 at 9:02pm

Last year was the driest my brother has seen in the 10years he has been in Indo.

They get water from the well & it nearly went dry. He will be happy with an early wet.

freeride76's picture
freeride76's picture
freeride76 commented Tuesday, 29 Sep 2020 at 7:41pm

Nice one Craig.

I’m glad you went into the pressure differential between CS and the subtropical high pressure belt.
That’s where the consistency comes from.
The cyclones are just cream on the cake.

cb's picture
cb's picture
cb commented Tuesday, 29 Sep 2020 at 8:15pm

Looks like it’s beginning already. Darwin had its wettest September since 1981 supposedly... also Craig what’s your thoughts on Japan snow season ? ( not that we can get there anyway ) Was in Canada 2010/11 for the snow season ( the last strong La Niña? ) and wow what a season it was !!!

Craig's picture
Craig's picture
Craig commented Wednesday, 30 Sep 2020 at 9:39am

I'm not totally across the effect on Japan, but La Niña usually means cooler weather across the country.

Contrary, the seasonal models for this event are predicting it'll be a touch warmer than normal and about average, if not a touch wetter across the northern half of the country

mick-free's picture
mick-free's picture
mick-free commented Saturday, 3 Oct 2020 at 10:45am

Be a later start to the season. If I got the year right Japan had 1/2m base new years eve 2010 and then it snowed 5m in the next 3 weeks. Be above average snowfall 15m+ in North

Mick Free FIFOFOMO

memlasurf's picture
memlasurf's picture
memlasurf commented Tuesday, 29 Sep 2020 at 10:40pm

What a cracker, MP had a good lock down over winter now spring and summer look good., make up for last summer dud.

FrankSurf's picture
FrankSurf's picture
FrankSurf commented Wednesday, 30 Sep 2020 at 9:21am

a summer when the mid might get waves and some of those january tropical storms coming down thru the continent after a string of scunker summers. bring it on

boykee's picture
boykee's picture
boykee commented Wednesday, 30 Sep 2020 at 9:28am

Would this be applicable for the NE coast of NZ?
Cheers

Craig's picture
Craig's picture
Craig commented Wednesday, 30 Sep 2020 at 9:32am

To a slight degree, most of the activity will be aimed west of NZ and that zone will just be on the edge of the activity. Hopefully it swings favourably your way and swell generating systems don't develop to far west and north.

boykee's picture
boykee's picture
boykee commented Wednesday, 30 Sep 2020 at 9:44am

Thanks for this!

Surfalot67's picture
Surfalot67's picture
Surfalot67 commented Wednesday, 30 Sep 2020 at 10:12am

The good old boys up here say just watch the mango trees lol. Heaps of flowers early (this year) means a bumper cyclone year apparently....

Walk around G's picture
Walk around G's picture
Walk around G commented Wednesday, 30 Sep 2020 at 11:10am

Looks like a summer of driving coming up for me then, I'm actually looking forward to a change of scenery though

freeride76's picture
freeride76's picture
freeride76 commented Wednesday, 30 Sep 2020 at 11:18am

Mango flowering in sub tropics is related to August night time temps , which is higher in El Ninos.

El Niño years have bigger mango crops anywhere south of Tropic of Capricorn.

Surfalot67's picture
Surfalot67's picture
Surfalot67 commented Wednesday, 30 Sep 2020 at 11:20am

Cheers FR - so its true!

donweather's picture
donweather's picture
donweather commented Wednesday, 30 Sep 2020 at 5:15pm

Ummmm except we’re in a La Niña and Steve was alluding to mangos and El Niño.

Craig's picture
Craig's picture
Craig commented Thursday, 1 Oct 2020 at 6:49am

Ha, that's what I also read..

JackStance's picture
JackStance's picture
JackStance commented Wednesday, 30 Sep 2020 at 11:50am

weapon

Breathe. Murdoch's empire will one day fail to control our minds.

shraz's picture
shraz's picture
shraz commented Thursday, 1 Oct 2020 at 10:32am

August is a long way from Summer, I tend to trust the mangoes! Maybe it's not related to the fruit setting on the trees but the extra La Nina rainfall meaning that the ones that can hang on through the cyclones grow bigger, rounder and juicier down the line!

Aardwolf2's picture
Aardwolf2's picture
Aardwolf2 commented Monday, 5 Oct 2020 at 3:30am

.

donweather's picture
donweather's picture
donweather commented Wednesday, 30 Sep 2020 at 5:13pm

Sorry Craig I don’t understand the blue and orange charts above. Can you please explain a little further what these are showing and what the colours represent. Thanks.

Craig's picture
Craig's picture
Craig commented Thursday, 1 Oct 2020 at 6:58am

Yeah for sure. So the charts shows the probability of above median MSLP for the three month period Oct-Dec.

So if it's orange, there's a 80-100% chance of it being higher than normal.

But if it's blue, there's a 0-20% chance of it being higher than normal, and conversely it's a 80-100% of being lower than normal. My labelling may have been a bit confusing.

Just Floating's picture
Just Floating's picture
Just Floating commented Friday, 2 Oct 2020 at 8:30am

Love these Craig. I know you're talking primarily about the effect it'll have on our surf activity, as an aside though what does it mean for weather temps? Hotter - colder, wetter - dryer? Specifically looking at the Cennie Coast of NSW - love summer days, hate hot nights haha.

The green wall's picture
The green wall's picture
The green wall commented Saturday, 3 Oct 2020 at 8:29am

Craig, this covers the next 3 months but will this La Niña effect have a continued impact going into autumn next year and what potential surf conditions we might expect in Victoria? Or are they unrelated?
Cheers.

dangerouskook2000's picture
dangerouskook2000's picture
dangerouskook2000 commented Saturday, 3 Oct 2020 at 2:46pm

Hey Craig, are we gonna drown in flood waters again around the tweed region? If the last La Niña was 2011/12 that's when Murwillumbah went under water and heaps of other spots, Lismore etc. Just wanna know if I need to get my inflatable pool pony ready.

BliinkyBill's picture
BliinkyBill's picture
BliinkyBill commented Sunday, 4 Oct 2020 at 5:33pm

SO weres going to be best for a returning surfer (been ten years) up in queensland GC going to be packed so looking up sunny coast

gekatmargs's picture
gekatmargs's picture
gekatmargs commented Monday, 5 Oct 2020 at 2:57pm

Hey Craig, with a negative IOD is there a likely hood of increased cyclone activity off northern WA this coming summer?

Glenatmargs

velocityjohnno's picture
velocityjohnno's picture
velocityjohnno commented Tuesday, 6 Oct 2020 at 7:38pm

Here comes some moisture:

https://www.theage.com.au/national/victoria/victoria-prepares-for-floods...

A more important data-point: when this cooler weather began on the 2nd, I noticed a slug climbing all the way up to the top of the gutter. I asked "Dude, what are you doing climbing up so high? You are going to dry out up there. Do you know about some heavy rain coming that I don't?" Now we have up to 100mm on the way in an event.

Anyone remember 2009 (I think) La Nina when inland country Vic was flooding heaps?

Craig's picture
Craig's picture
Craig commented Wednesday, 7 Oct 2020 at 8:58am

Yeah, the insects/fauna are usually in tune with these things.

Craig's picture
Craig's picture
Craig commented Wednesday, 7 Oct 2020 at 8:59am

Interesting reading in the BOM's latest tropical note..

"All surveyed international climate models predict La Niña will persist until at least January 2021. Climate models have recently indicated the strength of the current La Niña, based on sea surface temperatures (SST) across the tropical Pacific Ocean, may be relatively strong. For reference, SST across the Pacific Ocean during the 2010-12 La Niña were as cool as 1.5 °C below average during the peak of the event. While there is some model-to-model variation, current guidance suggests SST values may fall to similar levels in December 2020. While La Niña and its associated impacts are unique from event to event, there is normally a relationship between the strength of the event and the severity of the impacts. As such, there is the potential for significant impacts across much of Australia in the coming months if the current La Niña strengthens at the predicted rate."

http://www.bom.gov.au/climate/enso/#tabs=Tropics&tropics=Tropical-note

dangerouskook2000's picture
dangerouskook2000's picture
dangerouskook2000 commented Wednesday, 7 Oct 2020 at 7:59pm

thanks craig

Redmond Clement's picture
Redmond Clement's picture
Redmond Clement commented Wednesday, 7 Oct 2020 at 1:09pm

Negative IOD sounds positive for some juicy tropical developments in the North West. 2010 brings back many fond memories.

thedrip's picture
thedrip's picture
thedrip commented Sunday, 11 Oct 2020 at 10:20am

So for SW WA, smaller low period swells are coming is how I read the last paragraph? Not sure what it meant for the winds though.