Poster: A snowHead
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I love the climatological discussion chaps, I really do. I always look for the punch line first though!
I raise my £5 to £10 each way
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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P.s. is climatological a word seems right.
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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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@twoodwar, meteorological?
To be fair, I have no idea!!
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00z GFS would bring in an intensely stormy cycle from 26 February for about a week. Temperatures would be on the cool side with heavy snowfall for the northern Alps. The western end would see the heaviest snowfall, but with the stormy weather temperatures would also be up and down a bit.
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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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High degree of uncertainties in the forecast for the Alps in the upcoming week. It all seems to be dependent on what the high pressure will do. Will it move east and establish itself over the Azores or will it be more to the east over Iberia and influencing more the Alp region? The first would give quite a lot of precipitation , the latter less. Finally at least, a little shake up ....
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Crazy weather heading to 3Vs on 29th Feb and the following week I guaranteed as I arrive. This year I had crazy hot temperatures at 3300m in Chile and then in the space of about 3 days in Furano Japan had -28C and +8C
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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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Anyone recommend a site for good detailed, local Austrian weather conditions (particularly Sazburgerland). Snow-forecast.com has it raining ("skier's revenge") on Sunday/Monday which is a change from previous sunny and warm ("skier can cope with") conditions.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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altaski8 wrote: |
I agree @nozawaonsen,
Regarding the control run - I don't think it's very significant that the control is similar to the operational. In my experience, it almost always is. I only find it useful for comparing the operational run to individual ensemble runs since - I believe - they are run at the same resolution. But for that level of detail to be worthwhile, I generally only make the comparison within 120 hours.
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In my experience I find the control run is often quite different to the op run from 6/7 days onwards and more especially after 10 days (which I usually ignore anyway as its so far out). But this is usually dependant on the upcoming weather situation. During long periods of high pressure, both op and control will likely be very similar. Its when you have a mobile pattern with low and high pressure moving about continually, that I find the OP and control start to differ especially 6/7 days onwards.
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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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@Weathercam, 25th.
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In my experience, if the operational deviate a lot from the ensambles (mean), a control run that follows the operational forecast (outliner) give more weight that it is not an outliner. The control run has the same base as the operational, but all the ensambles have minor deviations from the starting base.
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You know it makes sense.
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jimmybog wrote: |
altaski8 wrote: |
I agree @nozawaonsen,
Regarding the control run - I don't think it's very significant that the control is similar to the operational. In my experience, it almost always is. I only find it useful for comparing the operational run to individual ensemble runs since - I believe - they are run at the same resolution. But for that level of detail to be worthwhile, I generally only make the comparison within 120 hours.
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In my experience I find the control run is often quite different to the op run from 6/7 days onwards and more especially after 10 days (which I usually ignore anyway as its so far out). But this is usually dependant on the upcoming weather situation. During long periods of high pressure, both op and control will likely be very similar. Its when you have a mobile pattern with low and high pressure moving about continually, that I find the OP and control start to differ especially 6/7 days onwards. |
Yeah I agree that differences widen the further out in time you go. That's true for all inter- and intra-model comparisons too. I just don't think it tells you much in the case of comparing the OP to the CONTROL. If the CONTROL and OP closely match in the long-range, but the ensemble spread is wide (or the run-to-run continuity or inter-model agreement is low), then the match is probably a coincidence.
In other words, I consider the CONTROL a check of the ensembles, not a validation of the OP. Its agreement with the OP is generally high (since they only differ in resolution) but also not very predictive of the validity of the OP solution.
In terms of forecast time frames, beyond 7 days I barely glance at the OP solution. But the ensemble mean has some predictive correlation. Beyond 10 days is nearly worthless IMO.
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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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@riman8, Bergfex.at
Unfortunately it is forecast to snow on Friday, then higher temperatures mean rain on Sunday/Monday, then a return to snow later next week.
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Poster: A snowHead
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Woosh wrote: |
In my experience, if the operational deviate a lot from the ensambles (mean), a control run that follows the operational forecast (outliner) give more weight that it is not an outliner. The control run has the same base as the operational, but all the ensambles have minor deviations from the starting base. |
I don't quite agree with this logic. The operational run in your example is an outlier by definition. If the control run supports the OP, that suggests that the deviation from the ensembles is not caused by the difference in resolution between control and OP. But it does not otherwise support the validity of the OP solution. In your example I would hedge my forecast towards the ensemble mean, because it might be picking up on something that the OP is missing. If on the other hand the control run was closer to the ensemble mean, I might discount the ensembles somewhat and assume the lower resolution was adversely affecting the solution.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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I believe the control is run at the same (lower) resolution as the ensembles. So it is a "check" for the ensembles. It provides verification that resolution isn't messing with the ensemble results.
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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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@riman8, you can look at ZAMG (Austrian national weather service) https://www.zamg.ac.at/cms/en/weather/weather-forecast/salzburg/heute_vormittag . Not really sure they are any better than any other source of weather forecasts. All of them are based on the couple of models which are discussed here. The forecasts do change (often a number of times a day), they dont really offer any more than general guidance especially a number of days ahead. For what its worth the two main models are currently suggesting slightly different weather outcomes on Monday for the easterly Tirol / Salzburgerland one mild with some precipitation (I guess either rain or snow depending on location) the other light precipitation first thing, starting cooler but becoming milder during the day.
Other forecast places with a focus on snow are https://wepowder.com/en and https://www.bergfex.com/oesterreich/wetter/prognose/.
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The 06z GFS not surprisingly caved to the ECM for Sun. night into Monday. Any snow is now confined to the highest elevations of eastern Austria. The shortwave is modeled weaker, with less cold air advection in its wake, and a much weaker cold push. A non threat on this run. Just a little light rain near and east of Salzburg.
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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 op and control are run with the same starting conditions. The op is run at high resolution. Each of the other ensembles has a small change to the initial conditions and is run at normal resolution. Thus if the op and control are different (and they are sometimes) then the issue is something to do with resolution not starting conditions. The mean gives you a flavour of the ensembles as a whole, but equally in blending out outliers (which a mean must do) it can give the impression that all outliers ate wrong which is far from always the case. @Polo and I have had many a ding dong about this and some place more emphasis on it than others. Fair enough. Anyway individual runs are inherently a lot less useful than building up the overall pattern over a number of runs and indeed eventually cross model consistency.
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@nozawaonsen, have you a synoptic chart to hand for the 29th as I bet that's there's a stonking low over Genoa or thereabouts.
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Yeah come on Noza. Give us some good news for the extreme south (Isola).
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On the GFS charts (06z) it looks like the best chance for precipitation south of the main alpine ridge comes wed/thur (26th/27th) next week. That's when the deepest trough swings through. Thereafter the parade of threats mostly seem to come from the NW again. I don't want to preempt anyone else's maps or opinions though.
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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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Weathercam wrote: |
@nozawaonsen, have you a synoptic chart to hand for the 29th as I bet that's there's a stonking low over Genoa or thereabouts. |
No stonking low over/near Genoa on the 6z GFS operational run. But there is a low centred over Northern Italy on the 26th, though its not a deep low and has very limited effect on precipitation anywhere in Northern Italy. In fact the entire operational run has very little precipitation south of the Alpine ridge. Ensembles may tell a different story when they are released, but I think its looking like February is going to end up mainly dry South of the ridge (same as its been the past two and a half months).
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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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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@Weathercam, your snowforecast image shows the snow being brought in on W/NW winds so unlikley to be a Retour D'est?
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There is a little action for the southern (and even southwestern) Alps on the GFS ensembles for the 26/27th. But precipitation amounts are relatively light and clustered around the OP. Ensemble uncertainty increases significantly thereafter with a wide spread and lots of activity.
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You know it makes sense.
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The geography of the Alps creates a natural tendency for low pressure near Genoa. But to actually get significant precipitation into the mountains from the south it helps to have a southerly component to the mid-level flow. And for that you want a high amplitude trof that passes over or west of the mountains.
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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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@leggyblonde, does look like that, but sometimes other low spirals off and develops - anyway looked at a few other resorts in the region Abries / Ristolas, Isola and Piemonte where you might expect to see similar precipitation and all looks a little fragile and probably just a blip.
Think I might be getting excited over nothing maybe as too far off ?
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Poster: A snowHead
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Quote: |
excited over nothing maybe as too far off ?
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Maybe but hopefully not!
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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@Weathercam, the 26th looks more like small amounts for the Dolomites etc not much around more westerly parts of Italy and the 29th does not look like a retour d'est to me, but I am hardly an expert. However both models are suggesting decent amounts of snow around the 29th for southern French alps but from the north west not south east, might be Briancon etc are the wrong side of the higher mountains.
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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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@munich_irish, the best situation is when the weather comes from the South and or frontal activity in the region.
It can also be extremely localised, and you'd expect to see varying amounts of precipitation across resorts in the area.
What's weird about this is the predictions for us in Serre Che yet surrounding Southern resorts do not fair as well.
Normally the Lautaret will block most of the accumulations (check La Grave forecast out) when the weather is from the N/NW.
As I said, could be an anomaly.
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You need to Login to know who's really who.
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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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@Weathercam, I think most of your screenshots are derived from the GFS Op run, which is a bit of an outlier. Much more likely to be fronts coming from the northwest. Recently these have been too weak to get far enough south / east to deliver any snow to Serre Chevalier / Lombardy / Dolomites etc., but next week's fronts have the potential to be a bit stronger - so some snow will get further south and east.
So my bet would be on some fresh snow for most of the Alps, but with the hotspots further north and west. You will probably get more than the Dolomites though!
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psyxologos wrote: |
luigi wrote: |
Skied from La Thuile over to La Rosiere today. At midday, the sun came out and it was showing 11C at 1900m on a chairlift thermometer. The soft corn snow was enjoyable, but it did feel a bit too springlike. Don't tell Whitegold that global boiling is back on!! |
I am travelling to La Thuile on Sunday. I really hope the temperatures will be nowhere as high as you say they were yesterday. Hopefully a snowfall this week, perhaps? Here is to hoping. |
There was report of 15cm there this week. Also, probably the best snow conditions I encountered over the 5 days I was in Aosta Valley were at La Thuile, the combination of catching enough out of the westerlies as they funnel through the Little St Bernard Pass and the NE aspect of many of the runs conserves it well.
La Rosiere gets a lot of sun from its southerly aspect, I expect it will be suffering from Spring conditions this weekend, but catch it as it softens and before it gets too sticky and it's nice. Looks hopeful for some colder weather and snow by middle of next week maybe??
Last edited by You'll need to Register first of course. on Fri 21-02-20 2:41; edited 1 time in total
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You’re looking in the wrong place. All the snow is falling in the north west of the Uk at the moment. It just won’t stop
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This is starting to look quite tasty for cold and snowy next weekend in western CH/PdS/Cham
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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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The last few GFS runs look crazy. Like a child has gone wild with an Etch a Sketch for the FI ensembles
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leggyblonde wrote: |
The last few GFS runs look crazy. Like a child has gone wild with an Etch a Sketch for the FI ensembles |
Not for the Dolomites. Looks like another 7 days of mostly dry weather. One half decent snowfall in 3 entire months. Absolutely unbelievable, even for a usually dry area like the Dolomites.
Looking good North of the Alpine ridge though. Lots of precipitation forecast with temperatures falling from Tuesday onwards.
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