Resource Snow prediction accuracy thread

Discussion in 'Alpine & Southern' started by Jellybeans, Aug 4, 2017.

  1. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    So this kinda explains it.
    An analysis of snow predictions from models, commercial forecasters and the government agencies. Just snow depths compared to each other. The brainchild of @The Plowking.

    This is the snow forecast according to the respective forecasters and models, for the 11-12 August period.
    [​IMG]
    Will fill in other parts of the table as we go...

    Please no snow predictions in this thread, keep them to the respective thread or BBQ.
    All chit chat and other talk to BBQ.
    Treat this as a recordbook to look at how the different forecasters perform.
    Over time, you could analyse the data and pick better forecasters for different types of events, etc.
    But this isn't a snow prediction thread, just a snow depth forecast analysis thread.

    Lets see how this goes...
     
  2. POW_hungry

    POW_hungry Part of the Furniture Moderator Ski Pass: Gold

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    What locale are you basing model data on? Major resort averages?
     
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  3. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    Was wondering when somebody was going to ask...
    Jane: Her call
    Grasshopper: His call
    Frog: His call
    BOM: Based on Perisher
    Yr.no: Based on Perisher
    Model output: Based on NSW Main Range/Perisher/Thredbo area.

    P.S. If anyone should be added, just say.
     
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  4. Rat trap bindings

    Rat trap bindings One of Us

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    Great thread idea!
    I'd like to throw into the ring snow-forecast.com as it is a worldwide prediction service with lots of info so for the period at Perisher they are saying 3cm. What effect though will the 80k wind prediction have I wonder?
     
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  5. Kelpieboy

    Kelpieboy One of Us

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    I think CC will be disappointed he hasn't been included ;)
     
  6. POW_hungry

    POW_hungry Part of the Furniture Moderator Ski Pass: Gold

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    It's GFS, so no need to complicate the anaylsis IMO...
     
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  7. nfip

    nfip Part of the Furniture Ski Pass: Gold

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    Great thread.
    Worth that we add AXR to the table pls. ?
    Or is it same as BOM you have included.
    It seems to have been on the money , at least in the 3 day window I accept , where others have been not so.
    Yes it is one of my go to
     
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  8. Belly

    Belly A Local Ski Pass: Gold

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    Great idea. But a few surfers have posted here, and I can't help but think of the wave size scale debate threads on surf forums.

    Key considerations for mine are; where will the measurements be taken (location altitude aspect etc), and when measuring over multiple days will the total 24hour reported numbers be added (best indicator of unsettled IMO) or will it be the net base change from the start date to the finish date?
     
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  9. Rat trap bindings

    Rat trap bindings One of Us

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    If it's GFS then why the prediction of 3cm that is more in line with Jane and The Frog..? Big difference between the raw GFS at 5 to 10cm. Surely the interest will be in the punter with out the skills of deep analysis like me that would like to see what the easy understood report accuracy is?
     
  10. POW_hungry

    POW_hungry Part of the Furniture Moderator Ski Pass: Gold

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    It is GFS as published on their site:
    http://www.snow-forecast.com/pages/faq#model

    In answer to your question, I don't know the locale/model run you have highlighted in that screenshot... GFS updates 4 times a day.

    This is another reason why Snow-Forecast shouldn't be included, it's NOT a reliable resource IMO - they don't publish the run timestamp (only their 'publish date') so God only knows when the data is from. Could be out of date for all we know.
     
  11. The Plowking

    The Plowking Part of the Furniture Ski Pass: Gold

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    Think 7 Days is easier

    11th August
    At 7 days
    GFS
    At 4 days

    11th August
    At 7 days
    AXSG
    At 4 days


    EC someone else, I dont subscribe to weatherzone and think it best we keep the same...pretty pictures...

    Will edit dates as per the op.
     

    Attached Files:

    #11 The Plowking, Aug 5, 2017
    Last edited: Aug 7, 2017
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  12. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    EC...
     
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  13. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    7 days will probably be easier as it aligns with AXS...

    AXS R and G are similar, will include them as one.
    BOM category details their Perisher (human) forecast.

    As I am using Perisher forecasts, I will use Perisher's 24 hour snow depths and stack them together within the particular event. I know Perisher's snow reporting isn't great, but it's the easiest option for me.

    As for snow-forecast.com, It is GFS with topography dressage.
    This. @Rat trap bindings No one is trying to be rude. I will think about adding snow-forecast.com, but I probably won't.

    And can we please stop the chit chat now. Just the snow predictions table and the model images from that particular day. Any additions or questions? Please send them via PM or take it to BBQ. All other chit chat to BBQ. Thanks all.
     
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  14. The Plowking

    The Plowking Part of the Furniture Ski Pass: Gold

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    @Claude Cat
    Thread clean please!

    Relevant posts are
    #1
    #12
    #13

    @Jellybeans1000
    Perhaps edit first post explanation?
    And we're at 4 days...
     
    #14 The Plowking, Aug 7, 2017
    Last edited: Aug 7, 2017
  15. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    [​IMG]
    3 day forecast...

    Model overview:



     
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  16. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    Next system, Tuesday to Friday next week. Leaving Saturday and beyond for the fairies...



    Most of the snow is forecast to fall on the Thursday and Friday...
     
    #16 Jellybeans, Aug 9, 2017
    Last edited: Jul 14, 2018
  17. Claude Cat

    Claude Cat On my bike Moderator Ski Pass: Platinum

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    IMO one tendency I've noticed is that systems tend to slip in dates. Eg the system ends up delivering a day later than when it first appears say at 196 (or more) hours.
     
  18. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    Hence why I am doing it. To see what happens to a system and get it recorded in a easy to read format. It does get tricky when it does slip. That's why I have given it such a wide range. If it merges with the next weekend system, I will merge the two records :)
     
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  19. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    So our first results are in.
    [​IMG]
    In summary, the models and the Frog got it right.
    The other 'people' forecasters got a little bit over.
    Synoptic of system below...
     
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  20. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    And for the coming system...

    Predictive synoptics:


    Edit: I added in Saturday, because it was part of the system.
     
    #20 Jellybeans, Aug 13, 2017
    Last edited: Jul 14, 2018
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  21. Rush

    Rush Pool Room

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    Best thread ever.
     
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  22. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    [​IMG]
    I did this Tuesday night, just forgot to hit the upload button....

    You might notice some changes, EC and yr.no have been merged, thanks to a revelation of mine.
    And I have added in WZ snow forecasts.

    Next update: Tomorrow Night
     
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  23. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    [​IMG]
    The results from last week's system.

     
    #23 Jellybeans, Aug 21, 2017
    Last edited by a moderator: Jul 9, 2018
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  24. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    [​IMG]

    Incoming two systems(Monday and Wednesday). I did this on Saturday, yet again I forgot to press post.
     
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  25. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    ####
     

    Attached Files:

    #25 Jellybeans, Aug 21, 2017
    Last edited: Aug 31, 2017
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  26. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    [​IMG]


    Latest system coming up....
     
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  27. Nidecker

    Nidecker One of Us Ski Pass: Gold

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    this thread could be really good :) But its missing something, I can't quite put my finger on it
     
  28. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    What would that be? Always up for improvements:)
     
  29. Wardy

    Wardy One of Us

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    It's tops. What were the results for the last two August systems...?
     
  30. Majikthise

    Majikthise Sage Moderator Ski Pass: Gold

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    Needs some points system to build a league table... ;)
     
  31. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    [​IMG]
    Results for the earlier system.
    I didn't keep going with the other one, because I was too busy skiing.
     
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  32. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    Will do, when it finishes for the season.
     
  33. Nidecker

    Nidecker One of Us Ski Pass: Gold

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    Thats the improvement I was looking for. :) I was being a little tongue in cheek, we all appreciate the time and effort many of you guys put into the weather thread .....
     
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  34. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    That's fine. I just didn't press the post button on that one.
     
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  35. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    [​IMG]
    This would be the current system....
    Taken Monday night, Saturday night and This morning. My timing be very off, but changing systems do that.
     
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  36. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    [​IMG]
    Current system.
    Previous system (BOO3) results out tomorrow
     
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  37. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    BOO3 results.
    [​IMG]
    So I added up all the reported snowfall totals at Perisher and Thredbo, and Falls for balance.
    It was really big at Perisher as you may know.
     
    #37 Jellybeans, Sep 14, 2017
    Last edited: Sep 15, 2017
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  38. The Plowking

    The Plowking Part of the Furniture Ski Pass: Gold

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    Absolutely unconvinced re perisher numbers.
     
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  39. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    Well that's the only data I got. Spencer's Creek unfortunately doesn't come in nice daily increments.
     
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  40. Undies

    Undies Pizza! Ski Pass: Gold

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    Image no load. :(
     
  41. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    Fixed :thumbs:
     
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  42. Undies

    Undies Pizza! Ski Pass: Gold

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    166cm?!?!??!? Wowsers.
     
  43. Alfred14

    Alfred14 Addicted Ski Pass: Silver

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    Very surprising to see such a massive difference between Perisher and Falls, first it was 5cm increments now its measure the deepest wind drift in the resort.
     
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  44. The Plowking

    The Plowking Part of the Furniture Ski Pass: Gold

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    Just put an * after perisher.
    Maybe thredbo is a better option?
     
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  45. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    Maybe. Thredbo has 133cm for their upper slopes for the period.
    I have asked the Perisher folk for some help.
     
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  46. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    @The Plowking got info from the Perisher forums, that Perisher snow reporting has been pretty good this year. Strong winds would have blown a lot of snow from the ranges onto leeward aspects (much of Perisher). So 166cm probably didn't fall down as snow at that particular spot over that week, but there was 166cm there because of windloading plus proper snowfall. And I thought Buller's westerly wind situation was confusing....

    So I just put Thredbo's obs in to kind of gauge how much snow fell across the area a little better. And I will probably just use Perisher's numbers for the big tally at the end of the season.
     
  47. The Plowking

    The Plowking Part of the Furniture Ski Pass: Gold

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    If every big resort recorded snowfall as a leeward measurement they all would have got a similar amount.
    Spencers creek real data makes a mockery of Perishers measurements.
     
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  48. The Plowking

    The Plowking Part of the Furniture Ski Pass: Gold

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    Didnt happen.
     
  49. Jellybeans

    Jellybeans Walking on a cloud Ski Pass: Gold

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    I was told that 147cm was the real number, and that sounds a little more realistic.
     
  50. The Plowking

    The Plowking Part of the Furniture Ski Pass: Gold

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    *leeward ;)
     
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