Resource Snow prediction accuracy thread

snowgum

A Local
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May 4, 1999
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Being self interested - at what point (hrs) out does a 'hope' / potential activity become a thing?
...Is it 72 - 96 hrs a rough estimate? (Hoping schl hols' trip benefits!)

Or only when the various models settle? So each system suite different?

...oh be great to know as to by how many degrees of latitude we missed the last few systems (ie. In terms of the northerly maximum of the 850mb freeze or 5400m point)? Feels like they've been south of Tassie (43-44+ deg)?
 

Jellybeans

Part of the Furniture
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Aug 24, 2015
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Being self interested - at what point (hrs) out does a 'hope' / potential activity become a thing?
...Is it 72 - 96 hrs a rough estimate? (Hoping schl hols' trip benefits!)

Or only when the various models settle? So each system suite different?

...oh be great to know as to by how many degrees of latitude we missed the last few systems (ie. In terms of the northerly maximum of the 850mb freeze or 5400m point)? Feels like they've been south of Tassie (43-44+ deg)?
For general information for systems, when the models settle together or about 4-7 days

The more precise details probably 24-72 hours
 
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Jellybeans

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New season, more predictions tables.
1BC3C8EA-ED54-4FC9-95C8-FA2C7A3ED597.jpeg
 
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Jellybeans

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Okay here we go, the end of season data dump is about to be incoming....

Firstly we start with a prediction table that I didn’t actually make at the time. I basically put together all of these stats together this afternoon.
06F57E6A-2B9E-4203-9F36-019866FCA854.jpeg

That’s just so we can actually document the May system we had this year.

Here is some model scans.

Of the 27th of May, first node:
C56297E8-92EB-4C62-A623-2454AD5B47EF.png


And of the 29th of May, second node:
1235FE44-237E-4633-81EE-D96C44918D22.png


Remember that the table stats are based on Perisher.
 

Jellybeans

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Another year, another comparative predictions table..... 2019 edition.

Firstly the disclaimer from two years ago.
Before I start this, I should mention the data errors.
For starters, some of my estimations may be incorrect. I also haven't got the predictions from the exact same time for each system, due to the fluidness of weather forecasts.
Errors on part of the forecasters featured include 'worded predictions', which I have had to estimate or not include. Grasshopper what the hell does 'the snow keeps coming down' mean??????

This year I examined 4 systems this year to add to the now reasonable wide catalogue of predictions accrued over the last three years. We now have:
  • 15 systems in the 4 day predictions table catalogue.
  • 18 systems in the 7 day predictions table catalogue.

They are roughly based around a 3-4 day and 6-7 day range. These are all based upon how far away the various predictions are from the storm total measured at Perisher. The median figure was used for ranges of figures. Points are based upon the bracketed numbers, with totals on the right. Here they are....

07715E5C-FCC6-46D9-8942-5EDA5E647F11.jpeg


This season we see a clean sweep from EC, followed by GFS and Weatherzone in the 7 day prediction category. 4 day category sees GFS take the title and EC just behind it.

Now we add this season’s data from the data of last year and the year before. Gaps in data from previous seasons are not noted.
3C2014E3-FF9E-48CB-9574-220D186BAFDB.jpeg
1D418EF7-C74F-41D9-BE21-4C09663CF554.jpeg


7 day category featured EC continuing it's reign at the top. GFS comes to the party this year at second, and ACCESS and Jane tied for third. 4 day category was again taken out by EC, followed by a tie of GFS and ACCESS, and Jane in third.

And there you have it, another solid season wrapping up. Thanks again to all :thumbs:
 
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Jellybeans

Part of the Furniture
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Okay, finally got around to doing last year’s totals. A few notes:
  1. Same old disclaimer around data collection, particularly around the snow forecasters who sometimes don’t give a number prediction or use ambiguous language (Grasshopper on MW is the big culprit, so much so I couldn’t do an accurate tally for them in the 7 day length category).
  2. First year I added in the Canadian/CMC/GEM model, so it has a column in last year’s totals, but not the running tally.
  3. I assessed 5 systems in the 7 day category and 4 systems in the 3-4 day category last year, bringing us to a total catalogue from the past 4 years of 19 systems in the 3-4 day category and 23 systems in the 7 day category.
They are roughly based around a 3-4 day and 6-7 day range from the snowfall system. These are all based upon how far away the various predictions are from the storm total measured at Perisher. The median figure was used for ranges of figures. Points are based upon the bracketed numbers, with totals on the right. Here they are....


BD9CECE7-4F63-4CBF-BDD4-040C3FCF914B.jpeg

2020’s big winner for the 4 day category was Weatherzone, wooden spoon went to ACCESS (Australian) model. Overall, EC is still the top followed by the other models and WZ, Jane, Frog, the Bureau and in last place the Grasshopper (and yes the bottom chart should say 2017-20!)

30ADE65A-218D-4A2B-A993-5DC2883C9754.jpeg

Interestingly ACCESS won this 7 day category, and was the biggest loser in the 4 day category for 2020. The weakest last year was the Frog. Overall, EC is still long and afar the leader, followed by the other two major models, WZ and Jane.
 

Lady Penelope

One of some lot ...
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Okay, finally got around to doing last year’s totals. A few notes:
  1. Same old disclaimer around data collection, particularly around the snow forecasters who sometimes don’t give a number prediction or use ambiguous language (Grasshopper on MW is the big culprit, so much so I couldn’t do an accurate tally for them in the 7 day length category).
  2. First year I added in the Canadian/CMC/GEM model, so it has a column in last year’s totals, but not the running tally.
  3. I assessed 5 systems in the 7 day category and 4 systems in the 3-4 day category last year, bringing us to a total catalogue from the past 4 years of 19 systems in the 3-4 day category and 23 systems in the 7 day category.
They are roughly based around a 3-4 day and 6-7 day range from the snowfall system. These are all based upon how far away the various predictions are from the storm total measured at Perisher. The median figure was used for ranges of figures. Points are based upon the bracketed numbers, with totals on the right. Here they are....


BD9CECE7-4F63-4CBF-BDD4-040C3FCF914B.jpeg

2020’s big winner for the 4 day category was Weatherzone, wooden spoon went to ACCESS (Australian) model. Overall, EC is still the top followed by the other models and WZ, Jane, Frog, the Bureau and in last place the Grasshopper (and yes the bottom chart should say 2017-20!)

30ADE65A-218D-4A2B-A993-5DC2883C9754.jpeg

Interestingly ACCESS won this 7 day category, and was the biggest loser in the 4 day category for 2020. The weakest last year was the Frog. Overall, EC is still long and afar the leader, followed by the other two major models, WZ and Jane.
Great analysis, @Jellybeans . Thank you :)
 

Jellybeans

Part of the Furniture
Ski Pass
Aug 24, 2015
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That's a pretty cool table. What counts as 4 days away? 4 days until first snow fall of the system? First significant fall of the system?
4 days before the system that I have reviewed.
Hey JB,

Can you cut this by month? Some modelling/guessing works better than others at different times of the year.
I’ll see what I can do.
 
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