Sudden Stratospheric Warming and a summer of swell?

Craig Brokensha
Swellnet Analysis

Last month I began making regular posts in the Swellnet forums about changes in the weather occurring in the atmosphere above the South Pole. The chain of events appears to be leading towards what's called a Sudden Stratospheric Warming, though it hasn't quite reached that classification just yet.

The mainstream press has also caught onto the unfolding story so you may have read about Sudden Stratospheric Warming there.

Irrespective of whether it offically becomes a Sudden Stratospheric Warming, the event will have an impact on Australia's weather this coming spring and summer.

The current event originated in the lower atmosphere (known as the troposphere) from a phenomena known as mountain torque. In simple terms, mountain torque is a change in wind flow caused by mountain ranges. In this instance, it's caused by the Andes Mountains of South America interfering with the southern polar vortex. The polar vortex is a stationary low pressure system positioned at each pole, circled by strong westerly winds.

The Andes, which rise 6-7km above sea level, sometimes disrupt the westerly winds, setting off mixed waves through the lower atmosphere (troposphere) which can propagate to the upper atmosphere (stratosphere).

Think of a steady flow of water hitting a barrier and then becoming turbulent downstream.

Regular disturbances aren't powerful enough to break through to the stratosphere, but on rare occasions it can happen with the turbulence altering the layers of the atmosphere: cold air will sink through the stratosphere, with the reponse to this being warm air lifted towards space. This is a 'warming' event. 

If the warming event is strong enough it can break down the polar vortex and even reverse the flow of the westerlies. This would be a Sudden Stratospheric Warming event (SSW), though they're extremely rare in the Southern Hemisphere with only one of them being identified since records began back in 1979. That lone example was in September 2002.

SSWs are more frequent in the Northern Hemisphere owing to the presence of large land masses and mountain systems that disturb the polar vortex flow. Except for the Andes, Antarctica is surrounded by mostly ocean and the flow is more stable.

When the sudden warming event occurred last month, temperatures in the upper stratosphere jumped from -80 to -5 degrees - a warming of 75 degrees (see graph below)

This is the earliest warming event measured across the Southern Hemisphere, with the 2002 event occurring on September 24th and 25th. However, it's just falling short of thresholds to be classified as a SSW event at the moment. There's been a wind reversal at 2hPa and this is forecast to occur at 5hPa in the coming days, but it has to occur at 10hPa to be classified as a true SSW event.

Even so, in the last 39 years there have only been six reversals of the westerlies at 2hPa and three times at 5hPa indicating that it's still quite a significant event.

Over the past fortnight there's been numerous deep low pressure systems tracking the Southern Ocean below Australia, however these are only an indirect influence of the warm stratosphere.

The warming event is linked to the Southern Annular Mode (SAM) which describes the changing latitude of the westerly wind belt - positive SAM means the westerlies are more polar, negative SAM and they track closer to Australia.

At present there's a strong positive SAM which has not only moved the westerlies towards the poles, but also strengthened them, resulting in the strong storm activity under the country.

It's believed the warming event - sudden stratospheric or not - will filter down to the troposphere around the start of October. We won't see any significant impact on surface patterns until then.

We spoke to Professor Ian Goodwin and he's expecting a similar spring and summer to that of 2002/2003 - the occasion of the last Sudden Stratospheric Warming - where continuous southerly swell events were guided up the Tasman Sea. The swells encouraged northwards longshore drift, flooding all the East Coast pointbreaks with sand. Goodwin called it "one of the more peculiar summers" he's experienced. Peculiar in the good sense. Surprising.

The drivers for this particular warming event have occurred above the Indian Ocean with the downstream regions - i.e Australia, New Zealand, and the islands of the western Pacific - feeling the most profound effects. In regards to the latter, the incredible seasons that Fiji, Samoa, and Tahiti have experienced are set to continue, while New Zealand may be cooler owing to a persistent south-west flow.

Lastly, it should be noted that this isn't linked to climate change per se and is a naturally occuring phenomena.

We'll continue to provide updates on this event over the coming weeks and months.

Comments

savanova's picture
savanova's picture
savanova commented Tuesday, 17 Sep 2019 at 6:14pm

Will the weather changes bring rain?

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 5:56am

I'm no expert on this, but the BOM are going with a no. The major influence will be a positive Indian Ocean Dipole (IOD), with less moisture available from the Indian Ocean, meaning less rain for most of the country and warmer weather.

Also negative SAM events are forecast by the BOM shifting the westerlies further north and bringing drier weather to the interior instead of the infeed of moist easterlies.

If there are these cut-off lows then we may see localised heavy rain events, IMO, but that's just my opinion.

//Amended to change "negative IOD" to "positive IOD"

fitzroy-21's picture
fitzroy-21's picture
fitzroy-21 commented Wednesday, 18 Sep 2019 at 8:38am

Historical data would agree with that for 2002.
http://www.bom.gov.au/climate/history/rainfall/

Westofthelake's picture
Westofthelake's picture
Westofthelake commented Wednesday, 18 Sep 2019 at 11:08am

Good one fitzy, well and truly dry as a bone in 2002.

velocityjohnno's picture
velocityjohnno's picture
velocityjohnno commented Wednesday, 18 Sep 2019 at 5:25pm

It's dry, Macca.

memlasurf's picture
memlasurf's picture
memlasurf commented Tuesday, 17 Sep 2019 at 6:50pm

How will it effect Victoria? Does it pass below then do a left turn and head up the east coast?

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 5:57am

If we get more negative SAM events as forecast by the BOM then there'll be more westerly influence in the winds and also swells with more west in them.

Nick Bone's picture
Nick Bone's picture
Nick Bone commented Wednesday, 18 Sep 2019 at 6:42am

Double shit. Why not.

I am the bone

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 6:47am

Ha.

Lanky Dean's picture
Lanky Dean's picture
Lanky Dean commented Thursday, 19 Sep 2019 at 11:07am

From memory, re Vic
Lots of offshore days with super strong winds for Mornington P I
Surfed joahana a bunch that year.
Great banks from memory.

memlasurf's picture
memlasurf's picture
memlasurf commented Thursday, 19 Sep 2019 at 11:14am

There is hope yet as Johanna faces the same way as the MP. Great banks but does your memory recall the rips? I think Johanna can rival Rippamatta on its day.

adsi's picture
adsi's picture
adsi commented Thursday, 19 Sep 2019 at 12:14pm

Rips at Johanna can often be much worse than gunnamatta

memlasurf's picture
memlasurf's picture
memlasurf commented Thursday, 19 Sep 2019 at 12:19pm

Definitely agree even at 2 foot.

Lanky Dean's picture
Lanky Dean's picture
Lanky Dean commented Thursday, 19 Sep 2019 at 3:41pm

Yes. I had some good boards with a nice amount of thickness. The rips didn't phase me as much as some.
Twas a great time.
The car ran on lpg 19 to 21 cents a litre back then.
Good to go !

crg's picture
crg's picture
crg commented Tuesday, 17 Sep 2019 at 7:47pm

Loving these articles Craig...interesting stuff! Hope that sand comes!

I'm not cheap,
But I'm free.

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 5:57am

Thanks crg, love trying to explain these tricky phenomena.

lives in hope's picture
lives in hope's picture
lives in hope commented Friday, 20 Sep 2019 at 5:55pm

post ya thumbnail image crg! Solid looking, cloudy?

crg's picture
crg's picture
crg commented Friday, 20 Sep 2019 at 6:44pm

Nah not Cloudy and not me. It's actually one of my favourite surf shots of all time of Jackie Dunn trimming in at second reef Pipe. I had it as a poster on my bedroom wall as a grom and every pixel of the image is embedded in my mind from staring at it every night.

I'm not cheap,
But I'm free.

lives in hope's picture
lives in hope's picture
lives in hope commented Friday, 20 Sep 2019 at 7:52pm

Yep actually remember the convo now you mention it. Classic shot. I dont feel like I see pipe shot that way much anymore. Its more about the money shot in the barrel. I like to see the set up, same as in vids I like to see the paddle and take off of a wave as well as the manouvres

Bnkref's picture
Bnkref's picture
Bnkref commented Wednesday, 18 Sep 2019 at 6:12am

75 degree temperature change is solid!

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 6:14am

And since reaching 0, the freezing mark at 8hPa..

 

Lanky Dean's picture
Lanky Dean's picture
Lanky Dean commented Thursday, 19 Sep 2019 at 1:50pm

Hot air rises.

garyg1412's picture
garyg1412's picture
garyg1412 commented Wednesday, 18 Sep 2019 at 7:49am

So Craig if a positive SAM pushes the westerlies towards the south pole is there a chance we will get more stable high pressure events in southern Australia meaning less wind but with longer period W/SW swells from the stronger storm activity way further south.

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 7:51am

Ah, so right now we've got a + SAM, hence the polar activity, but forecasts for when the warming filters down into the lower atmosphere have more - SAM events, so westerlies moved up towards Australia.

bigwagon's picture
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bigwagon commented Wednesday, 18 Sep 2019 at 8:02am

Any guesses as to what effect this may have on the summer trade wind belt?

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 8:09am

The flow on effect with more - SAMs would be it moving further north than normal.

bigwagon's picture
bigwagon's picture
bigwagon commented Wednesday, 18 Sep 2019 at 4:13pm

Thanks Craig, so drier conditions than normal could be expected for SE QLD.

freeride76's picture
freeride76's picture
freeride76 commented Wednesday, 18 Sep 2019 at 9:02am

I think you got the IOD arse about Craig.

It's a positive IOD which restricts moisture infeeds into Aus, not a negative IOD.

Also, that negative SAM displacing the tradewind belt further north is terrible news for east surfers from Seal Rocks north.

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 9:05am

Ah yes you're right, all this +/- SAM and +/-IOD I got a little mixed up, but the premise of the comment stands.

The current IOD which is positive will lead to drier weather across Aus. Will correct comment above.

freeride76's picture
freeride76's picture
freeride76 commented Wednesday, 18 Sep 2019 at 9:09am

copy that, I thought that was what you meant.

Duesouth's picture
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Duesouth commented Wednesday, 18 Sep 2019 at 9:36am

Fascinating article Craig, thanks. Any idea why this winter the scenario set up? The Andes are always the speed bump for the westerlies, have you seen anything unusual in the position of the jet or some other climatic/weather event in relation to the Andes that has caused the knock on effect?

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 10:04am

Yeah not totally sure. Ian was indicating that the positive IOD event might be a factor, but major storms or distrubances (more so than normal) moving across the Andes looks the main cause identified by others.

atticus's picture
atticus's picture
atticus commented Wednesday, 18 Sep 2019 at 10:21am

Excellent article, Craig. I understand little about the weather beyond what immediately effects me, however yourself and Ben have a knack for showing the relevance of broad-scale patterns. I've turned more than a few heads mentioning the Long Wave Trough at barbecues and this summer I'll have another conversation starter!

truebluebasher's picture
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truebluebasher commented Wednesday, 18 Sep 2019 at 10:30am

Great read Craig...firstly tbb has to ask if this is your (Bongo van) photo...if so, hurrah!
https://hellomanly.com.au/

BOM has a great simple interactive OZ model = [Summer + Polar] vs [Winter - OZ]
http://www.bom.gov.au/climate/sam/

Science reckons crash test dummy SAM drives the epic westerly wind dust storms

Winter/Spring -Sam stirs up the Cocky's Red Wave that choc tops the NZ Alps
https://watchers.news/data/thumbs/798_296/2013/01/dust-storm-australia.jpg

Sept 2009 Sydney Red Wave Surfers
https://secure.i.telegraph.co.uk/multimedia/archive/01487/sydney-2_14871...

https://lh3.googleusercontent.com/-x9w6_yXs73otEQ6FQK6masekSP1sWwyQU7qrw...

https://img-s-msn-com.akamaized.net/tenant/amp/entityid/BBPXXtA.img?h=39...

https://www.abc.net.au/news/image/1439270-3x2-340x227.jpg

https://nnimgt-a.akamaihd.net/transform/v1/crop/frm/pLj4pq4ybq6tTvnKybAX...

https://en.wikipedia.org/wiki/2009_Australian_dust_storm

Aug 2019 Qldurr for Ekka Westerlies-'Slammin' Sam' unleashed a pretty Pink Wave.
tbb surfed same girly Pink Wave to Pacific horizon line & back (0-10kms visibility)
"Do we blame arsonist SAM for fuelling & fanning recent spate of SEQ bush fires?"
https://higginsstormchasing.com/tag/sam/

Again, great article Craig...shows how greater Oz is toyed by offshore weather events.

Kellya's picture
Kellya's picture
Kellya commented Wednesday, 18 Sep 2019 at 10:47am

I agree, absolutely love this stuff. So interesting just scratching the surface of what is such such a complex field of study.
If this event leads to a strong - SAM pushing the westerlies further north, wouldn't that mean wetter conditions for us over in the West? Or is that only the case during - SAM events during winter?

Kellya's picture
Kellya's picture
Kellya commented Wednesday, 18 Sep 2019 at 10:54am

The BOM link provided by TBB above answered my question! As I thought the westerlies not pushed anywhere near high enough during summer to see any increased rain in the West. Cheers

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 11:10am

Yeah thanks crew, really interesting stuff and can't wait to see what pans out!

jimbrown's picture
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jimbrown commented Wednesday, 18 Sep 2019 at 11:11am

Hey Craig, can you clear something up for me. You state that the drivers for this particular warming event have occurred above the Indian Ocean. Are you referencing Ian's suspicion that the IOD has played a role?

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 11:18am

Yes but also it looks like mountain torque played a part, as you can see in this diagram, the green line (bottom diagram) is an increase in mountain torque from South America through August. The warming event did look to start south of the Indian Ocean it appears. So that probably doesn't clear up your question any more sorry. Looks like both played factors?

ojackojacko's picture
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ojackojacko commented Wednesday, 18 Sep 2019 at 11:16am

Hi Craig.

>>The drivers for this particular warming event have occurred above the Indian Ocean with the downstream regions - i.e Australia, New Zealand, and the islands of the western Pacific - feeling the most profound effects

Any thoughts on what it might mean for swells going up through the Indian Ocean (i.e. Indo)?

Thanks

Craig's picture
Craig's picture
Craig commented Wednesday, 18 Sep 2019 at 11:19am

Unfortunately can't answer that one for you.

ojackojacko's picture
ojackojacko's picture
ojackojacko commented Wednesday, 18 Sep 2019 at 11:24am

no worries - thanks :)

hang on - unless that's because you're planning a strike mission yourself ...
:)

t-diddy's picture
t-diddy's picture
t-diddy commented Monday, 23 Sep 2019 at 7:46pm

You probably can't answer this either but..
What effect will this have on swell-genesis in WA?

Craig's picture
Craig's picture
Craig commented Monday, 23 Sep 2019 at 8:36pm

Yeah, closely linked, I wish I could sorry.

OHV500's picture
OHV500's picture
OHV500 commented Wednesday, 18 Sep 2019 at 12:15pm

Just back from 2 weeks in the Banyaks - were we had S/SE and some SW all day, every day. (lucky we had some breaks that could handle the swell and the wind.) We were discussing the IOD regarding this.
Craig - Would the SSW increase the IOD or Vice versa. Or am I totally confused ?

thermalben's picture
thermalben's picture
thermalben commented Wednesday, 18 Sep 2019 at 12:28pm

Craig did an article in 2015 that touches on this.
​​​​​​​https://www.swellnet.com/news/swellnet-analysis/2015/10/14/why-winds-wer...

truebluebasher's picture
truebluebasher's picture
truebluebasher commented Wednesday, 18 Sep 2019 at 12:32pm

W.A. (SAM version plugs into IOD) + ENSO variable...[ tbb recommends WA Govt link ]
https://www.agric.wa.gov.au/climate-weather/climate-drivers-south-west-l...

Island Bay's picture
Island Bay's picture
Island Bay commented Wednesday, 18 Sep 2019 at 3:11pm

We love "cooler with more SW winds" over here. Great Wellington weather and swell.

It pumped again today.

Duesouth's picture
Duesouth's picture
Duesouth commented Wednesday, 18 Sep 2019 at 3:32pm

Amen to that IB...2 weeks upcoming in early October down the bottom end, look foreword to confirming the flow on effects of the SSW!

rob tas's picture
rob tas's picture
rob tas commented Wednesday, 18 Sep 2019 at 3:37pm

I read that the fires in Nth NSW and QLD are a direct result of this SAM effect - driving of hot westerlies (unusually) across the continent (exacerbated of course by nutters putting a match to something)

Randymcbrown's picture
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Randymcbrown commented Wednesday, 18 Sep 2019 at 4:42pm

Thanks fellas for all the weather info. Do you feel these events will benefit S.A.'s Mid coast and Yorkes next month or so with the more intense westerly storms below.? (Like the nice burst of swell we just experienced).

dez's picture
dez's picture
dez commented Wednesday, 18 Sep 2019 at 5:04pm

Love these kind of articles folks. Thanks.

velocityjohnno's picture
velocityjohnno's picture
velocityjohnno commented Wednesday, 18 Sep 2019 at 5:33pm

OK speculating:

Stratospheric warming comes down, negative SAM pushes westerlies further up, it's summer so Tasman is warmer - does this mean more chances of ECLs once any fronts go past Gabo Island into the Tasman?

davetherave's picture
davetherave's picture
davetherave commented Wednesday, 18 Sep 2019 at 9:33pm

have to wouldn't it? when two air masses collide and over a warmer ocean? nows the time to bring the kp index in as well vj. correlation, correlation, correlation.
i for one will be interested to see this interconnection play out.

davetherave

greg-n.williams's picture
greg-n.williams's picture
greg-n.williams commented Thursday, 19 Sep 2019 at 10:22am

Interesting! I remember that 2002 summer very well! Have to be an improvement on what we experienced last summer on the Mid Nth Coast with constant Nor/Easters & the resulting small short period wind-swell for day after day for 2months @ least! Bring it on.

Paddy O'Brien's picture
Paddy O'Brien's picture
Paddy O'Brien commented Thursday, 19 Sep 2019 at 12:02pm

Great article Craig! It's super interesting the way you break it down to make it more understandable. Any idea what effect this may have on swell directions? In the article you mention that in 2002 "continuous southerly swell events were guided up the Tasman Sea" and then in the comments say "there'll be more westerly influence in the winds and also swells with more west in them." Does this suggest prominent westerly west swells for the Victoria coasts? Or swells that track in a more southerly direction towards the Victorian coasts and then up through the Tasman? I know it's very complex but just wondering what you think will play out over summer (particularly for south west vic)
Cheers

Straighthander's picture
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Straighthander commented Thursday, 19 Sep 2019 at 2:04pm

In your article you state “At present there's a strong positive SAM which has not only moved the westerlies towards the poles, but also strengthened them, resulting in the strong storm activity under the country.” this not what is said in the last paragraph of this article https://www.abc.net.au/news/2019-09-06/rare-weather-event-over-antarctic...
Or this climate report http://www.bom.gov.au/climate/outlooks/#/overview/video
Both state negative Sam in the coming months and westerlies moving north, with hot dry conditions. Are you just talking in the present. Cheers

Craig's picture
Craig's picture
Craig commented Thursday, 19 Sep 2019 at 5:43pm

Yeah that’s present. Hasn’t filtered down into the troposphere yet. 

pcrisp's picture
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pcrisp commented Thursday, 19 Sep 2019 at 5:47pm

aliens doing some engine testing down there?

truebluebasher's picture
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truebluebasher commented Sunday, 22 Sep 2019 at 9:15pm

Thanx for the Warning Craig + new swellnet alien sensor is working a treat!

(Here comes SAM...ready or not) W > # < E winds collided, flattening the Nullarbor
Be sure to check out each of these vidz...WOW! Some ominous signs ahead crew...

Thursday 19th-21st Sept..SA /NSW ...Vic ? Dust Storm 100km/hr Temp (30* > 16*)
7 Double Play >> [Check Rad Wind Chart] + Railway vid same page. OK!
[ WARNING PIGS MAY FLY ]
https://7news.com.au/news/traffic/dust-storm-sweeps-across-central-nsw-f...

9 vid starts the same but travels toward the coast for shoreline shots!
https://www.9news.com.au/videos/dangerous-dust-storms-in-south-australia...

Video Date -Sat 21st 2019 (am) NSW Highlands footage (Winds 139 kms/hr)
https://abcnews.go.com/International/video/dust-storm-creates-orange-haz...

Sat 21st Sept 2019 (pm) NSW coastline 'Grey Wave' (Thunderduststorm)
Gotta love the beachgoerz...Nah! That's not a storm! WTF
https://cdn.newsapi.com.au/image/v1/aac69f00eeaa4a582ab12ae790d10410

tbb is unsure if this was one huge system or two hard strong sweeps like Qld.
Seems that if they come as one we get the Red Wave..
Qld got Pink Wave & NSW got Dark Grey Wave (tbb thinks that's a good thing?)

(Note tbb recorded SEQ Pink wave prior to Qldurr Fires + Thunderduststorm mid fires)
Qldurr firies reckon the Smoke fuelled the Anvil shape Thunder Clouds.(Native style!)

Southerners best be on the alert for Bush Fires on the back of these devil winds!

21st September 2019 What in the hell are you freaks whipping up down there.
Dutto is headed your way chasing them green aliens, better check under yer beds!

https://www.bbc.com/news/av/world-australia-49783230/meteor-lights-up-pa...

http://space.trendolizer.com/2019/09/moment-fireball-meteor-lights-up-ni...

Craig's picture
Craig's picture
Craig commented Monday, 23 Sep 2019 at 10:29am

Quoted from Ski.com.au below.. This is the SAM through the atmosphere, surface at the bottom, stratosphere up the top and the dotted line out current date (forecast to the right)..

"Finally we are going to start to see the SSW anoms drop towards the troposphere.

A little -AAO just before the turn of the month.
But the focus is on October and November now."

velocityjohnno's picture
velocityjohnno's picture
velocityjohnno commented Monday, 23 Sep 2019 at 8:13pm

So that big blue blob will move down as we go right?

Currently it's red (23rd of Sep)... that may change at sea level?

Come on blue blob

Craig's picture
Craig's picture
Craig commented Monday, 23 Sep 2019 at 8:37pm

Yep, hopefully!

Craig's picture
Craig's picture
Craig commented Wednesday, 25 Sep 2019 at 1:16pm

We could finally be something happening around the 10th of Oct, looks like the SSW is filtering down into the lower atmosphere.. Here's the forecast chart for the SAM

savanova's picture
savanova's picture
savanova commented Friday, 27 Sep 2019 at 10:52am

Ill be in fiji then will i need to pack a rhino chaser?

velocityjohnno's picture
velocityjohnno's picture
velocityjohnno commented Sunday, 29 Sep 2019 at 10:46pm

6th October, do we see 1st ECL forming off passing front and NSW low combining in the Tasman? Oct 10th, even bigger low on NSW south coast?

Craig's picture
Craig's picture
Craig commented Monday, 30 Sep 2019 at 5:35pm

It's still taking it's while to filter down.. SAM forecasts are toying with a strong negative event, but we still wait and see..

Craig's picture
Craig's picture
Craig commented Tuesday, 1 Oct 2019 at 7:11am

Forecast is looking more promising for it filtering down...

Mcface's picture
Mcface's picture
Mcface commented Tuesday, 1 Oct 2019 at 1:29pm

Just needs to hold off a couple more weeks for my return. I expect that my SN subscription covers postponing the weather to a more convenient time?

Tim Bonython's picture
Tim Bonython's picture
Tim Bonython commented Wednesday, 2 Oct 2019 at 6:42am

Hold the phone! Somethings emerging.

Distracted's picture
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Distracted commented Thursday, 10 Oct 2019 at 11:05am

Craig, do you reckon this cold burst of air up the east coast could be related to the stratospheric warming?

Craig's picture
Craig's picture
Craig commented Thursday, 10 Oct 2019 at 11:16am

I personally feel these cut-off systems and good run of SE swell for the East Coast is somewhat related. We're about to head into a weak negative SAM and move in the westerlies northward, and we may see this continue into the end of the month.

Looking here it hasn't totally filtered through to the troposphere but it looks like there are some weak effects..

velocityjohnno's picture
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velocityjohnno commented Tuesday, 22 Oct 2019 at 6:07pm

So 22 October now and that was quite a nice swell event Vic just had. Grey skies and westerlies, 6ft or so of swell peaking over a 3 day period. Not bad. Saturday morning was 6 degree low iirc, so a wintery feel.

There was the horror week of SE winds beforehand, but overall the grade is going back up to B-.

A normal Spring intense low system Craig, or did the SSW jig something that helped it?