A Most Unusual Summer
A Most Unusual Summer
It’s been an unusual summer for surf across the country.
While the heat is there, East Coast readers are more than aware of the extended run of poor surf while those in the southern states are counting their blessings as the Southern Ocean continues to fire.
This isn’t the norm.
South-east wind slop and the sound of cricket on the radio is what most Victorian’s and South Australian’s associate with summer, while prolonged flat spells and heat waves dominate the west.
South Australia making good this summer (Chris Lovell)
On the East Coast, Queensland and northern New South Wales can generally rely on prolonged easterly trade-swell events that provide weeks of persistent swell energy, with southern NSW also benefiting albeit with a little less size and consistency.
Alas it’s all been flipped on its head.
The typical surface pressure pattern seen through summer is one where high pressure dominates the mid-latitudes with a semi-permanent high setting up across the Indian Ocean and Great Australian Bight with another setting up in the vicinity of New Zealand’s North Island - see the chart below left.
This setup is thanks to the subtropical high pressure belt shifting south in response to increased tropical heating and lower pressure across our northern regions.
Under such a setup the Southern Ocean becomes more subdued as cold fronts and lows are effectively steered away and blocked from pushing close to the Australian mainland, while the ‘flat-topped-high’ setup across New Zealand produces persistent easterly trade-swell energy, ebbing and flowing with the deepening and weakening of embedded tropical depressions.
Instead, what we’ve seen this summer is the complete opposite, and while the reason is not yet known the Mean Sea Level Pressure anomaly analysis from the start of December up until now paints a clear picture of how unusual it is.
Rather than high pressure sitting where it should be, we’ve had lower pressure than normal across the Southern Ocean and directly east of New Zealand - see chart below right.
What our summer usually looks like (left) and the Mean Sea Level Pressure anomaly for December and early January (right) (NOAA)
This has created multiple days of large, pumping surf across Western Australia and great waves across South Australia with even the sheltered Mid Coast offering waves for weeks on end.
Victoria has been a little more hit and miss, yet the've had more than enough quality surf days owing to the lack of strong south-east winds.
Western Australia's deep water reefs roared to life multiple times through December (Swellnet surfcam screenshot)
This pattern left the East Coast in the doldrums with only two notable swells through December. Meanwhile, the New Year has got off to one of the worst starts in recent memory.
The cause, as touched on earlier, is so far unknown, but combine this with the very late cool signal across the equatorial Pacific and overall warmer than normal sea surface temperatures, and it appears that this summer will end up being an outlier.
Looking ahead and the Southern Ocean is again firing up with the Western Australian coast expected to see further large pulses of swell for the coming fortnight, while the Tasman Sea will also likely see an out of season low forming later next week.
While not the typical summer swell producer, it will be much welcomed across New South Wales, while Queensland will likely have to wait until February before the first proper trade-swell of the season arrives.
Weird times indeed.
Comments
Had a decent trip back to SA over the break. Better than normal and got good to very good waves down south, at Yorkes and on the mid.
Thanks for the update, I have been wondering what has been happening. I'm looking at the charts recognizing all the patterns but obviously I don't know the cause of why this is happening haha.
FWIW Craig and the forecast crew have donned their sleuth hats and are trying to solve the mystery.
Make shipping dirty again.
"A study led by Pacific Northwest National Laboratory has found that 'dirty' ship emissions – usually releasing sulphur aerosols into the Earth's atmosphere – actually help to produce a cooling effect on the planet, mitigating some of the global warming from greenhouse gases."
Thanks Craig...
Hope it is an outlier and Huey makes up for it come February!!
Look at that southerly wind anomaly over NZ North Island. SST here was 22C on 26/11, and 17-18C when we got back on Tuesday. Yikes!
And the anomaly is in no hurry to shift.
See the low that develops east of NZ tomorrow and lasts for the better part of a week.
MSLP forecast for Saturday:
Yep and on one day last week it got down to just over 16 degrees IB while you were away. Relentlessly windy too and combined with cold water i've been regularly getting cold in steamer. Coldest summer I can remember West coast NZ
Thanks Craig, love this content!
Would this explain warmer than normal water temps here in SA (mid and south coast)? My son's watch (not that I believe it) recorded water temp of 25c on the mid recently. This maybe an inflated number but it is the warmest I can recall here....not sure if anyone else agrees?
25 seems a bit too warm but it definitely was comfortable in boardies and a top most days down south etc (other than first thing in the morning). I reckon low 20s. Maybe a touch warmer on the mid.
According to an aquatics instructor at port noarlunga in mid december it was measured at 22c and only seems to have warmed a little since then. I also think this past winter was warmer than usual on the mid and putting it down to lack of rainfall?
Yeah latest observations inside the gulf along the coast are about normal. 21-22°C or so but could be warmer right close to shore. And it's also warmer up the gulf and inside Spencer Gulf.
The Victor region and further offshore, especially the Bonney Coast etc are all a bit warmer than normal thanks to the lack of upwelling south-easterlies.
Here's the observations temperatures, and then anomaly below it..
Cheers Craig....yeah the less than normal SE flow would explain a lot. Be interesting to see how late summer into Autumn progresses. Thanks
Long time reader 1st time commenter, love these articles & can’t wait for the analysis / theories.
For WA, definitely more summer waves than I can remember, seems like less west coast troughs this year which would feed the High in the Bight. Low pressure forming off NW coast then tracking West not East, what is the Indian Ocean Dipole doing?
7 day Indian Ocean model looks like mid-winter with multiple big L-pressure systems, storm track is further south but plenty of waves for Indo / WA / SA ahead.
That onion off the E coast of NZ has been a common theme these past few months. A blocking low where a blocking high usually exists. Have the SST's been higher there than usual?
There is a significant warmer than normal pool sitting just east of them which could be aiding things, but it's only really got that warm since about Christmas..
Anomalously warm water in the Tasman/NZ corridor where high pressure should be sitting has been my working hypothesis.
There's just not enough significant temperate gradient between the West Pac warm pool and Tasman/NZ corridor for air masses to form significant pressure gradients.
It’s it just me or does NZ seem the major beneficiary of all or any atmospheric synoptics, systems or patterns? Seems like they have had the run of runs over the last few years.. strongly considering moving to the land of the long white cloud (and swell lines)
Probably been geographically long over wide helps too?
What ya think?
Yeah, being a long island and the ability to easily jump coasts is favourable. But still, it can be quite a drive between quality spots from the west coast to east coast. Paging IB.
At your service!
Yes, mostly endless Southern Ocean swell for the west coast, but fickle in the east. Also, only a few sheltered spots in the west (including where I am).
NZ is definitely the land of the long windy drive; no coastal highways like Aus where you can just check spot after spot.
Condition update: underwhelming swell, 4-5C cold anomaly water, holiday crowds. I had much better waves in N NSW. But things usually revert to good-pumping
Can concur IB. Colder water than ever whole west coast and some very sloppy windswept conditions lately. I've done some hours though post Christmas with the crowds. I've just come over east this week looking for the mythical long range predicted north swell but it's still a myth. North swells on the east coast of NZ that are from Northern hemi storms may show up on modelling but are usually a hoax. East Coast water is also only 18 or 19 usually way over 20 by now. Lots of bronzy sharks around too in the bay of plenty. I better come back west tomorrow
Can see the anomalies here..
As can Tassie be.
It's been alright as a summer here in Vic. Warm, humid and muggy. Reasonably consistent cycles of fronts going over, muggyness turns to northerlies with clean surf of good size, then gets cooler. Enough offshore days, but still quite a few SE days. I'd expect the Mornington side has been even better.
I thought you were at the mornington side vj ?
Don't tell me you are stuck down there in juc
? Say it ain't so .
Bird rock looking fun ?
Here in SA for summer I normally forget about the boards and concentrate on the mountain biking but this summer has been exceptional with good waves down south and reasonable peelers on the mid for the frothers.
Even Day Street got some solid 4ft face waves with a magical bank that popped up delivering consistent righthanders a week or so ago.
Yorks would have been going off a few times too but didn't have the chance to get over there.
Enjoy it while its there south aussies - maybe we get a good winter as well or is that too much to wish for ??
Ahhh the good old Daystreet right. My bread and butter for many years growing up across the road from it. Good memories. Enjoy!
Gotten pretty small the last week here however weather wise, it's the best summer for weather on the Sth Coast in over 4 years. The last 4 years have been brutal howling ESE winds, but this summer is much more pleasant and like a proper summer, alot more light winds and warm water. Can handle the ocean going quiet for a bit in exchange for a bit of good summer weather.
Won't b long til she fires up again no doubt.
Wondering if all the anomalies occuring off the East coast are part of a bigger picture that includes all the massive swells in the North Pacific this year. As noted in the Kip Caddy interview. Thoughts?
Don't think so,
I'm no forecaster, northern pacific run of swell has come with the usual weather looks like a blocking high has set up over the PNW
With the jet setting up running north to south
Creating sant Ana winds
Causing all sorts of havoc on the west coast.
Been offshore and big every day this week.
Trend looks to continue as the trades set for Friday sat sun .
Blocking high usually sets up every Jan
Freezes all the mountains to iceblocks
Messes with the snow packs .
Our memories are short term though
As it was stormy and flat through 2 weeks in December.
I've observed it but have no explanations SR- maybe Craig has something to add.
It feels more El Nino this summer on the Surf Coast rather than the La Nina which has been predicted. Quite dry generally, and it seems like more hot days than last summer. Some decent swell and a few offshore days as well. Probably more S and SW than SE which we cop a lot of in La Nina I thought. I am sure the Easterlies will come. The whole weather unpredictability thing seems to be getting scarier. How's those fires in California in winter.
Think it's actually a nuetral year, yes winds wreaking havoc on LA to SD
Weatherman did put out alerts before hand
Pretty standard weather further north
Let's talk about the jet stream though
Word for the day wind shear.
Looks like the jet push down hard on the basin.
Bloody great chat cheers all :)
Those wild fires on the west coast are ridic crazy. Wowzers ;(
Hard to see those images coming through. Drove the west coast over 3 weeks a few years back - while there was an outbreak around Big Sur (contained) this is just hard to fathom and take in
would be lost for words to experience it as I am sure many are :(
Safety paramount