 Poster: A snowHead
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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| moffatross wrote: |
The UK Met Office are envisaging a bit of wind and rain carried on the jet stream riding over the European high pressure which builds more strongly by late December, and perhaps sinks again, letting the Atlantic back at the north as we head into NY. Not a hint in their wording of an undercut, or any cold from the east via a Scandi High, or a northerly plunge out of a Greenland High or even a mid-Atlantic toppler.
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UK Outlook for Tuesday 13 Dec 2016 to Thursday 22 Dec 2016:
It'll be dry and bright for most, but patchy overnight frost and fog are likely in the southeast. Through the week periods of wet and windy weather are expected to move across the UK from the west. The most unsettled conditions are likely across the north and west, with drier and brighter weather for southern and eastern areas. It'll be windy at times, with the possibility of gales in the west and northwest, but it will be much less windy further south and east. By mid December there'll probably be some longer, drier spells between the wet weather, perhaps heralding a change to something generally more settled. It'll be fairly mild initially but temperatures are likely to return closer to normal, although passing weather systems may raise them at times.
Updated at: 1140 on Thu 8 Dec 2016
UK Outlook for Friday 23 Dec 2016 to Friday 6 Jan 2017:
Whilst there is a good deal of uncertainty for this period, it is most likely that more settled conditions may dominate associated with high pressure affecting the UK. If the pressure does build, then we can expect drier than average conditions for most areas with lighter winds. Temperatures are also then likely to be below average with an increased risk of frost and fog, especially where skies remain clear overnight. There will probably also be some milder, unsettled interludes though, and as we head into the New Year this may become more of a feature in our weather, with the greatest likelihood of changeable conditions in the northwest, giving rain here at times.
Updated at: 1141 on Thu 8 Dec 2016 |
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Significantly, the UK Met Office's update today suggests that they expect high pressure to sit around central Europe for the foreseeable future.
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Forecast summary
Regional UK 5 days UK 6-30 days
Outlook for the UK over the next 6-30 days
UK Outlook for Wednesday 14 Dec 2016 to Friday 23 Dec 2016:
As we move through next week we are mostly likely to see a north-west to south-east split developing. During this time periods of wet and windy weather are expected to approach the UK from the west, however their eastward progression at this stage is fairly uncertain. In this type of scenario the most unsettled conditions are likely across the north and west, with drier and brighter weather for southern and eastern areas. It'll be windy at times, with the possibility of gales in the west and northwest, but it will be much less windy further south and east. It'll generally be mild with temperatures above average, however, in between weather systems temperatures will return closer to normal.
Updated at: 1222 on Fri 9 Dec 2016
UK Outlook for Saturday 24 Dec 2016 to Saturday 7 Jan 2017:
There is a good deal of uncertainty for this period as the UK remains in a battleground between higher pressure across the near continent and lower pressure in the Atlantic. The exact orientation of these will dictate conditions across the country. Currently western parts are most likely to see outbreaks of rain at times, along with relatively mild conditions, whilst eastern areas will see drier and perhaps colder conditions. There will probably also be some milder, unsettled interludes though, especially into early January, with the greatest likelihood of changeable conditions in the northwest, giving rain here at times.
Updated at: 1223 on Fri 9 Dec 2016 |
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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people can post what they want surely, I quite like the speculation and watching how forecasts change
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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@kitenski, sure, but if it's based on the far end of FI or beyond they can expect stick for it given how unreliable models are well known to be at that range.
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@davidof, Wow, not been down the valley (further than Bourg) for 3 weeks. I knew thy had invoked the reduced speed limits but I hadn't realised how bad it had got. Probably won't help arrivals into Chambéry tomorrow!
As for 50% forecasts, I recall sitting in the Station weather brief at Gibraltar. After the usual stuff for the fliers, the senior British Officer on the Rock, a naval commodore. asked of the met man - will it be an easterly or a westerly? This was purely to determine which beach he intended to sail his dinghy from rather than anything military. The met man pulled a coin out of his pocket, tossed it and pronounced "Easterly Sir". Much giggling from the cheap seats!
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Jellybeans1000 wrote:
I wouldn't say it's completely inaccurate. EC Monthly Control has about a 40% accuracy between 10-20 days.'
I can predict a coin toss with 50% accuracy.
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Sure, but weather isn't a coin toss! While most of us on here pretty much reduce Alpine weather systems to 2 possible outcomes (will it snow or won't it?) there are always many different possibilities.
It's more like predicting the roll of standard 6-sided die (or probably more like a D20 or a 2D6 if you want to get RPG-geeky...). If you could do that with 50% accuracy, you'd be pretty smart (and make a fortune in casinos).
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Was it 2014 when people spent Christmas in bone dry ski resorts only to get trapped by snowmaggedon on the way out. Some people took 36 hours on the drive home. There was then a week of excellent skiing for the NY folk followed by heavy rain at altitude which washed the snow away except in the highest ski areas. Misery.
In the Vercors yesterday, they need to get those canons a bit closer I think.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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@davidof, yes it took me 17 hours to drive in from Lyon , but at least there was snow. Not going this year so not stressing but do feel for all the holiday people.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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Ah, cracks starting to appear and the people divided (optimists vs pessimists...?).
With regards to the discussion about forecast reliability and FI and so on, I largely agree with @Jellybeans1000. I think we all go above and beyond to disclaim any discussion of longer term forecasts, just in case anybody in here doesn't fully understand the unreliability beyond a certain point. Beyond that, this is a discussion of the weather outlook, and it would be crazy for us to stop talking about forecasts for fear that someone took them too seriously and got upset.
The idea of discussing FI in here is that many minds sharing information and reflecting on and criticising each other's observations helps us get closer to the truth. In some cases, the truth might be that there is a genuine trend in the models 12 days out and it narrows the range of possibilities thereafter. In others, it might be that there is no certainty and we haven't a clue.
Alongside that, sometimes it's just fun (for some of us at least) to look at snowy charts / imagine those outcomes / enjoy a moment of hope.
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No sunny perch in Australia, it actually snowed today in the hills today. Taking a look at the fresh EC long term data now.
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Sorry, I just assume that anyone in Australia is on a sunny perch...
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- the far end of GFS is really just a set of possibilities and changes from run to run. You might start to see a pattern forming, you might not, but I would never consider it to be a forecast (in that context downgrades or upgrades in far FI don't really make much sense).
- my view (and that's all it is) is that complex discussion of Rossby waves and MJO is by and large better for weather forums (rather than skiing forums). Though clearly post what you want.
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I don't see the problem with talking of upgrades and downgrades. Some charts offer more in the way of promise, as they offer pathways to positive outcomes despite not being reliable forecasts; when a worse outcome comes along on the next run, offering less hope and a more unappealing path forward, I can't really see the problem with referring to that as a downgrade.
Regarding that other point, don't worry, I'm not about to start a discussion about Rossby waves. Really just mentioned it in passing while trying to make a point.
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I can predict a coin toss with 50% accuracy.
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Don't know if you're being deliberately facetious here, but if not, you may have missed the point. Sure, 40% accuracy is poor (although useful...) if there are only two outcomes, but with the weather there are so many outcomes that 40% accuracy is actually pretty impressive. Of course, usual caveats...
Regarding models, they're not great, but let's not panic just yet. Cold upstream in America is fuelling intensification of the polar vortex and putting more energy into the jet, which may yet help to dislodge the euro high or otherwise get precipitation to the Alps. The high does still appear to be pretty sticky, however, and despite a lobe sliding westwards, this other segment ridging northeast still threatens to keep central Europe dry.
I'd guess the best chances at this point might be either the eastern/northeastern high sinking or flattening and systems coming over the top, or alternatively a system breaking off and splitting the high, as the latest ECM showed. That scenario would at least take care of France and the southern Alps.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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@Dashed, Or it's just the ones that are willing to stick their necks out.
Sorry everybody for my long and now somewhat redundant post. Had internet problems and couldn't post. Didn't check latest responses before eventually posting my own.
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Actually WellingtonBoot, Rossby waves look quite interesting . . . 
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You know it makes sense.
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okay, okay Weather gurus Noza et al,
Greetings from a lovely warm and only slightly precipitous Ireland... most unfortunate in snow respects cos for great snow in ze Alps we need that blocking high to shrink south and those lovely storm fronts to come in over Ireland and Scotland before freezing over the Alps....and yielding their beautiful bounty!!!
On forecasts, i think they are getting better and better each year tbh, with most reputable forecasts giving a reliability indicator (typically expressed as a % indicator) according to the probability of being close to correct. And critically that will do for me.
So to my question: where is there most likely to be good snow from Dec 28th on say???
p.s. this is taking into account current snow on the ground, weather for the next 10 days (blended probability as we move out) and likely mean reversion to some sort of seasonal norms for the period from the 20th on (which usually happens btw).
p.p.s. for me for now, (& I am no guru  ) , the most likely places for good snow that stick out are North America (unfortunately), Japan is too much of a hike , Norway too bloody cold and dark this time of year, but any suggestions on any hidden gems!?!
p,p,p,s let it snow, let it snow, let it snow
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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@horgand, Well that's certainly one way of getting your point across forcefully...
Others might have more to say on this than I do, being on the ground and having seen conditions up close, but I would guess you're best off heading somewhere that already has good conditions. It sounds like high resorts along a portion of the French-Italian border are a good bet, Val d'Isere seems to be skiing well over much of the mountain, and beyond that it is difficult to say. Austria has good snowmaking in many places and Ischgl seems to have a lot open, but without new snow, which is far from guaranteed right now, anywhere relying exclusively on snowmaking might be struggling by the 28th.
@Jonpim, Oh I know. But I'm not sure that discussion is welcome on here...
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Poster: A snowHead
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| horgand wrote: |
So to my question: where is there most likely to be good snow from Dec 28th on say???
p.s. this is taking into account current snow on the ground, weather for the next 10 days (blended probability as we move out) and likely mean reversion to some sort of seasonal norms for the period from the 20th on (which usually happens btw).
p.p.s. for me for now, (& I am no guru ) , the most likely places for good snow that stick out are North America (unfortunately), Japan is too much of a hike , Norway too bloody cold and dark this time of year, but any suggestions on any hidden gems!?! |
Georgia
https://www.facebook.com/gudauri.georgia.186/posts/105861013239146
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Incidentally, the EC monthly model is pretty nice, as it shows the Atlantic blasting in several times starting from the 18th and carrying on over the Christmas period.
I can potentially still see some systems getting through with more energy in the jet, but as well as the ordinary amount of caution (and low angular momentum tempering the strength of the jet), my experience is that these blocks are resilient, often more so than is forecast initially.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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They're going to taunt us, these models. Suddenly the GFS 12z has a significant little system coming through at only t120. No good for France or Switzerland but could bring 5-10cms to Austria.
I remember it was there 4 or 5 days ago, and then disappeared (of shifted East a few hundred miles), before making its return now.
As likely as not it will miss again next run, but certainly one to watch.
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You need to Login to know who's really who.
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UKMO looking up on the 15th?
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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The trend's your friend. That's worth looking for. Random shots from single runs at +384 or beyond is really only going to show you that the operational run fluctuates a lot at that range. I have seen little to suggest long term forecasts (15 plus days) can do much more than give you a very general outlook and that with a relatively low level of skill. It's fun, but don't take it seriously.
12z GFS op and control both now going very cold in the Alps 18/19 December, but overall it remains a very dry outlook for the majority of the Alps.
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| WellingtonBoot wrote: |
| Quote: |
I can predict a coin toss with 50% accuracy.
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Don't know if you're being deliberately facetious here, but if not, you may have missed the point. Sure, 40% accuracy is poor (although useful...) if there are only two outcomes, but with the weather there are so many outcomes that 40% accuracy is actually pretty impressive. Of course, usual caveats... |
Well as weather in analogue and chaotic, there are infinite outcomes, so to be truly accurate - to predict exact temperature, wind direction, humidity, snowfall inches etc across even an isolated area is impossible. Obviously the forecasters give a range of outcomes within which the forecast is determined to be either accurate or inaccurate, but without knowing that range that 40% figure is meaningless. For example, for statistical purposes, the Met say a forecast is accurate if actual temperature it is within 2 degrees of predicted, but I expect for long term forecasts forecasters use a totally different metric and scale, so that 40% figure may either be impressive or barely better than guessing.
Last edited by You'll need to Register first of course. on Fri 9-12-16 20:18; edited 1 time in total
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@Evan Roberts, same thought occurred to me.
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Any sign of any snow in the Dolomites next week?
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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My understanding (which might well be erroneous) is that for rainfall forecasts, for example, the proof of the accuracy of these forecasts is empirical. If there is a series of forecasts which give a 40% chance of it raining on a series of occasions, and if, after the event, it has indeed rained on 40% of those occasions, then the forecast was 100% accurate. If it rains on 10% or 90% of those occasions, it was a pretty duff forecast.
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Atlantic / European jetstream is still in a funny place and stuck there.
Little fresh snow until January.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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@Whitegold, quite possibly. Then again could come sooner.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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| pam w wrote: |
| My understanding (which might well be erroneous) is that for rainfall forecasts, for example, the proof of the accuracy of these forecasts is empirical. If there is a series of forecasts which give a 40% chance of it raining on a series of occasions, and if, after the event, it has indeed rained on 40% of those occasions, then the forecast was 100% accurate. If it rains on 10% or 90% of those occasions, it was a pretty duff forecast. |
But there is a big difference between showery light rain in the early morning and a torrential downpour that lasts all day. More importantly for us snowheads, is the precipitation going to fall as snow or rain? And if it falls as snow at the top of the mountain and rain in the village, is the forecast correct or not? So any useful metric needs to tell us, within a range, the amount of precipitation and the freezing level, and needs to differentiate one ski resort to another down the road, where the weather may be very different, not just the result for a whole region.
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The weather outlook from my window is snow - which is annoying since I keep having to go out and scrape it off my drive.
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You know it makes sense.
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But there is a big difference between showery light rain in the early morning and a torrential downpour that lasts all day.
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yes indeed, but if you look at the met office forecasts they will be sectioned during the day and distinguish between light, medium and heavy rain. With percentages.
No general forecast is going to differentiate between one side of a mountain and the other. I live at 1550m one side of a little (1900m) mountain and the main village is on the other, 100 metres higher. Very different weather sometimes, particularly visibility, because the clouds move up and down the valleys in different ways. You kind of get to know, but it's unreasonable to expect a forecast to tell you that, surely?
Forecasts aren't bad at freezing levels but even then, as temperature doesn't drop with altitude in a consistent way (depends on humidity, let alone inversions which can mean snow at 1200m and rain at 1800). And the pluie/neige limit varies too.
It's all too confusing - best just to look out the window.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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@Evan Roberts, the range of that 40% figure is for exact correctness. And for Long term forecasts beyond 12 days, 40% accuracy is very good. EC dominate all short term, long term and seasonal prediction forecasting. GFS needs to lift its game.
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Poster: A snowHead
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@Jellybeans1000, what on earth does "exact correctness" mean? If you are saying at 20 days it can exactly predict temperature, precipitation and wind then I don't believe you. So what does it mean?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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is this a weather e fight?
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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You need to Login to know who's really who.
You need to Login to know who's really who.
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@scotspikey, no it's just a push back against irritating mumbo jumbo b*llshit. There's nothing wrong with loving speculation and charts, but specious claims for the ability to make long term weather forecasts, backed up by voodoo statistics do more harm than good.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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| langball wrote: |
UKMO looking up on the 15th?
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French TV have just spotted that with a significant weather system tracking across the alpes on the 16th (Friday) according to their forecast. I assumed it was just to encourage some Christmas bookings which have been described as "catastrophic" for some ski areas - although probably catastrophically good for others that actually have snow like Tignes.
Last edited by Anyway, snowHeads is much more fun if you do. on Fri 9-12-16 23:15; edited 1 time in total
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I'm in your corner nozawaonsen. Now make it snow you *$£%
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@davidof, ha remembering well how the good burghers of Obertauern tend to rub their hands in glee in poor snow years in Austria...
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| nozawaonsen wrote: |
| @Jellybeans1000, what on earth does "exact correctness" mean? If you are saying at 20 days it can exactly predict temperature, precipitation and wind then I don't believe you. So what does it mean? |
Not at all. I am talking about the how the accuracy is measured, not the accuracy itself.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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| nozawaonsen wrote: |
| @scotspikey, no it's just a push back against irritating mumbo jumbo b*llshit. There's nothing wrong with loving speculation and charts, but specious claims for the ability to make long term weather forecasts, backed up by voodoo statistics do more harm than good. |
Just relax, will you please. I have stated that the best long term forecast has 40% accuracy based on exact observations. I'm not making any 'specious claims for the ability to make long term weather forecasts'. People have the right to see data like this and it does good because it gives people perspective.
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| pam w wrote: |
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But there is a big difference between showery light rain in the early morning and a torrential downpour that lasts all day.
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yes indeed, but if you look at the met office forecasts they will be sectioned during the day and distinguish between light, medium and heavy rain. With percentages.
No general forecast is going to differentiate between one side of a mountain and the other. I live at 1550m one side of a little (1900m) mountain and the main village is on the other, 100 metres higher. Very different weather sometimes, particularly visibility, because the clouds move up and down the valleys in different ways. You kind of get to know, but it's unreasonable to expect a forecast to tell you that, surely?
Forecasts aren't bad at freezing levels but even then, as temperature doesn't drop with altitude in a consistent way (depends on humidity, let alone inversions which can mean snow at 1200m and rain at 1800). And the pluie/neige limit varies too.
It's all too confusing - best just to look out the window. |
Tis all Balderdash, exactly just look out the window.
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FAQ
