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Discussion in 'Alpine & Southern' started by POW_hungry, May 31, 2017.
Other than 1.5m at end of sept.
Water fall like effect freezing cold air (brown) subsidence filters down into troposphere.
EC has backed off the strat impact a bit today but GFS ensembles goes hard.
Still looking significant
Why doesn’t it show on this graph
It dropped below 1.5m in the week commencing 19 September.
Heading south from Nowra about 11am.
Well that's a happy looking face
Looks a little more deranged than happy I'd say... (Flip the image)
EC ERA Interim showing a bit of interest in Sept 11 on todays run.
Just arrived in Perth. Pouring rain like Perth only does and actually quite cold. Wishing I had a 3rd layer.
Wont snow then
I'm at Falls
Thought this was pretty cool:
Image is from 2015 - not current conditions, but worth a look. Selwyn in the north hanging on...just.
...and link to higher quality / file size versions
I see a little top-up on the 25th-27th:
looking well into + thinks ens too kick off september. Hello spring right there.
Jeezus those -AAO anomalies in the upper stratosphere are deep as.
Now we just need it to propagate down to the troposphere.
EC ensembles throwing up a good sized anom, first few days of September.
Could be a September to Remember if that happens... And perhaps sustained by another plunge in the AAO?
But the LWT for that period has weakened beyond recognition in the latest GFS model prog. Not saying it can’t happen, but if it does it probably will be more like the 25-26th system IMO.
I’m thinking a few days later.
Yeah the AAO should plunge in the first 5-10 days of September. So I’d expect the best period to be 8-14th of September, noting LWT alignment.
EC LWT has other ideas.
Yeah fair enough, there is some support on EPS for something around 2nd-4th. Still not sure about it's degree of strength.
-AAO support would probably back something around the 9th to 14th.
Dynamic models v climatology models, dynamic for me.
Noise smoothed out looks blocking.
What does 500hPa heights look like?
Well I've got no idea how it plays out but will be hoping for top ups to maintain the cover near peak levels till this possibly -AAO and LWT alignment in second week of September.
So often the problem at this time of year is the thaw kicks in and mid September dumps do little to stop it. September dumps are more about freshies for those lucky enough to have the chance to ski it. Can't complain though if this week is the peak, its turned into a much better season than I expected!
Weddel Sea gradual seasonal departure from Anomolies on ERA 5. Cant get Gif to download but its evident. Spring is on its way.
Still as seen many times a rogue cold system can pop up until december.
For anyone interested - I put into a spreadsheet all recorded peak snow depths at each snowy hydro site since records began and threw in a trend line for good measure.
Why? Someone argued with me that snowfalls have been increasing year on year for the last decade and I didn't think that was correct. Anyways the data is there for all to see, I just took the time to throw it together. Will update for 2019 and keep this going yearly.
I think you've put in the wrong Three Mile Dam plot.
I'd suggest ten years is not a very long time span to be identifying trends over - short term climate fluctuations would be enough to hopelessly bias the result.
As an example if you did the same things for the 90s you'd get a mighty fast decline in snowpack that would not be a very good representation of the reality since and that could lead to one reading all kinds of rapidly approaching catastrophic global warming scenarios into the equation. The reality would be that Pinatubo probably in combination with one or two other factors like a strong la nina in 1990 (from memory) was the actual cause of the trend by providing a very large positive anomaly in the first three years of data.
It's data all taken from the snowy hydro website, you can check it for yourself if you don't trust or believe what I have posted. edit: the data for 3 mile dam somehow overlapped with Deep Creek... will update
The general point to this data is simple: the trend is down. I'm not here to argue the why or how, simply showing the data. People can do with it what they please...
Interesting. Could be a variance in heights due to mean wind direction. Would be interesting to see a bias correction methodology applied.
Yes there could be any number of factors impacting the data, if I had the knowhow and time I'd add more analysis to it. But sadly I do not, perhaps someone else can pick up where I left off
3 things struck me when looking at all of the data:
Major dumps of snow took some years from terrible to great;
The seasons appear to be delayed further and further into August and September with a steep falloff
The lower altitude 3 Mile Dam trend line is significantly steeper than higher elevations. Indicating a retreating snowline.
All in all it was an interesting exercise
Great work Stu.
Just seeking clarification re the Three Mile Dam trend being steeper. Is the cm/yr number bigger, or are you saying this on the basis of the visual slope on the graphs? Latter not such a good approach due to different vertical scales on the three graphs.
means @ 1
The low peak CM anomalies - much greater in the last 2 decades than those proceeding it
Eh? No comprende. Are you saying the negative residuals from the trend are bigger in magnitude closer to the present? Maybe. But still seeking clarification about the linear trend slopes.
Indian Ocean Dipole is now very positive, as predicted by forecast models:
Sadly, I think the tap will be turned off for a while...
The wattles are out, the sky is blue and the wind is from the west - typical August scene down the coast when the snow is on!
The trend line for Three Mile Dam has gone from about 63cm to 35cm - a 45% decrease over 63 years. Compared to Deep Creek (125cm to 95cm - 24% decrease over 61 years) and Spencers Creek (220cm to 175cm - 21% decrease over 64 years). That is a pretty substantial difference.
GFS the only model that goes against its own ens mean runs.
Thats a corker.
The cmc thinks there is a good cold snow system passing the alps @29, then ridge builds in with mild dry days too follow.Too the west behind the ridge is warm tropical moisture thinks cmc. (LR)