The graph that is displayed shows precipitation and the 850mb temperature forecast including the current GFS forecast runs (each run is the same forecast but with tweaked input data) and an average of all those runs. The average historical data (from 1971-2000) is shown by the red line, the current forecast by the green line, and the average of the last dozen runs by the grey line. The thick blue line is the current forecast, but run on older 'lower resolution' software.Each other line is the same forecast with the tweaked data.
FI is unreliable long range, one could argue that anything outside 24-48 hours is unreliable, but then you can look at the agreement in the models, if all the lines are in agreement that gives you a high confidence in the forecast, you can see the further out you look the more apart the various lines are.
IMHO of course!!
Greg
Last edited by Well, the person's real but it's just a made up name, see? on Wed 24-11-10 11:39; edited 1 time in total
The GFS ensembles switched colours a little while back. Green is the operational run, ie the dominant forecast in high resolution, blue is the control run, which is run at a slightly lower resolution, when they both agree it is worth noting it. The mean is grey, the red is the 30 year average. +168 is in FI. Have fun.
see that mass of cloud coming off the south east corner of iceland... is that bringing our next dump of snow?
snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
shoogly, yes, ECM has the low pressure between Iceland and Scandanavia ploughing down through Scotland and going on to deal out snow to much of the UK by Monday... High parts of Scotland should certainly pick up quite a bit of snow, the rest of the UK is quite battlefield with each run and each model switching snow options back and forth, sometimes heavy snow, sometimes sleet, sometimes rain...
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.
looks like very warm weather in french alps by end of month, freezing level back above 3000m?
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
The 12z GFS ensembles maintain the same pattern for the Alps out till about 03 December. Deep cold for the next few days and some fresh snow, potentially quite a bit in the west and to the south on Friday. From Sunday it starts to warm up peaking around Wednesday, there looks to be quite a lot of snow around, though depending when it falls it will be rain to about 2000m.
However, the warm temperatures don't last long and by Thursday temperatures are dropping again, it looks possible that the precipitation in Austria may coincide with this and so though it will be less heavy will be snowier to a lower level.
At the 03 December the spread goes wide. The operational would go right back into deep cold. The control over the top of seasonal averages...
Interestingly though the mean keeps a gradual rise towards seasonal... at the end of the run... And still ends up around -5C at 1500m.
Here are some ensembles.
Obertauern
(Which chucks in a cheeky extra bout of snow on Sunday).
Wengen (?) [edit: thanks Brian! This is actually further south and closer to Saas Fee - and being further south is picking up more snow on this run]
Here comes 18z...
Last edited by So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much on Wed 24-11-10 22:48; edited 3 times in total
brian
brian Guest
nozawaonsen wrote:
Wengen (?)
Saas Fee.
Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
Arno, I'd go Geneva if I were you....we're off to Zurich and don't want any competition
Seriously, we're booked to Zurich and currently thinking about where to go from there (Engelberg, Andermatt...possibly Klosters). Let us know if you end up going for Zurich - would be good to do a couple of laps together (I suspect we wouldn't be able to keep up with you for long )
Poster: A snowHead
Poster: A snowHead
ChrisWo, currently trying to find an open hotel in andermatt...
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
Hmmm
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?
nozawaonsen, Hmmmm???? Is this a good HMMMM or bad?
Shimmy Alcott, yes - but that one doesn't show them on a map
Then you can post your own questions or snow reports...
Then you can post your own questions or snow reports...
MoodyFFS, ah
After all it is free
After all it is free
Quote:
Is this a good HMMMM or bad?
To be honest it is hmmmm!!!
If it was cold enough and this came through it would blanket the country in brutal blizzards.
If was just the wrong side of cold it would blanket much of the country (the south) in heavy winds and rain.
The arrival of a deep low (not necessarily quite as deep as in this run) at the end of the month has been recurring for a while now... the question is what the temperature would it be when it hits... A similar question for the Alps too...
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You'll get to see more forums and be part of the best ski club on the net.
nozawaonsen, well your more in the know than me lol!!! They are saying that this cold spell will stay with us for possibly 2 weeks , so at least the mountains should benefit from this, maybe not low levels but the mountains would be a compromise!!!
Ski the Net with snowHeads
Ski the Net with snowHeads
Ricklovesthepowder, I'm sure snow will fall to low levels in lots of places in the UK over the next fortnight and quite possibly quite large amounts. Where, when, how much at any given time and how long it will last is very tricky to tell. It is looking like a pretty good start to the season for Scotland (and in Europe for the Alps). What that means for the rest of the season... well not much really. A number of the LRFs were pushing a cold start to the season with things warming up later in winter. Then again...
snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
Even though i dont understand the maps graphs and what ever else you throw at us, if its blue then i smile After everyone of your posts i always have a grin on my face, keep it up lol!!!
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.
Ah sorry, I hadn't seen your one - I had the other one in my favourites . Nice one - except you've got to know where your resort or area is to get the wigglies! Which I don't always know Can you do a list along the side like the other wigglies map so I could just look for, say, Courchevel?
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
Bit of a shuffle this morning.
The end of November low pressure that was crashing through the channel on last night's models has been downgraded substantially and pushed south. This removes the chances of some of the more extreme options (for blizzards and or heavy rain) in the south of the UK for next Monday, Tuesday and Wednesday, but keeps things colder - arguably a much better outcome... Keep an eye on this though as it wouldn't surprise me if the deep low pressure option makes a come back... Further north, Scotland is lining up for more snow...
Back in the Alps... the likely snowfall for tomorrow seems to have been upgraded pretty much everywhere and a second band is now looking likely on Sunday. And that low pressure does still have an impact as it arrives in the Alps on 30 November/01 December, temperatures looking to rise slightly less high on Tuesday and some of the more extreme snow options looking less likely, but quite a bit of snow west and south. All in all though at this point it is looking like a fairly snowy week over the Alps for the next seven days...
Off in FI it is looking like a more pronounced cool down next Thursday into Friday and after that there is still a massive spread, only the 00z has the operational running high and the control running deep, whereas yesterday's 12z had it the other way around with the operational deep and the control high. The mean keeps it just below seasonal average... to the end of the run...
Keep an eye on this though as it wouldn't surprise me if the deep low pressure option makes a come back...
... Well that did not take long.
It's back and bad to the bone in 06z...
Will it, won't it. Chances are this would be snow and then heavy rain for a lot of the south of the UK... Not really ideal to be honest... It wouldn't need much to shift it into a full on blizzard, then again as this morning's earlier run showed it wouldn't take much to shift it south and downgrade it either...
Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
Yet another newbie weather question: a few days back the suggestion seemed to be that around the start of December temperatures could rise in the alpes, with the potential for rain. Does this morning's run suggest that the warmer temperatures are less likely to occur, or are more likely to arrive a few days later instead? I'm reading this thread anxiously as I want to book an Xmas trip to the southern alps and don't want to book it, only to find that all the snow at resort level gets washed away next week.
Poster: A snowHead
Poster: A snowHead
nozawaonsen, perhaps you can help me. I'm getting a little confused by the relationship between the GFS and the chart above. Presumably the chart above represents the so called "green line" forecast, but I note the former is at 500 hPa whilst the latter is at 850 hPA. I'd assumed that the 500/850 were metres above sea level and so 850 might give a better representation of resort forecasts (for resorts at 850m and above!). I've noted also that there is often quite a difference between the 500 hPa and 850 hPA charts: http://www.wetterzentrale.de/pics/Rtavn1442.html
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
Colin Bell, As I understand it the 850 hPa chart shows the contour of the 850 hPa pressure level which is nominally at 1500 m.
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?
milzibkit, I wouldn't worry too much what the immediate impact of some weather next week would be on a trip for Christmas.
The likelihood remains that the temperatures will rise a bit next Tuesday/Wednesday as the low comes through. Quite what the low looks like, where freezing level will be and what path it will take will become clearer over the next few days, but even if it brings rain to lower slopes it will bring snow up high. Overall I think that is a good thing! Moreover as it comes through the Alps it is more likely that if it did start with rain it would turn to snow on this run.
And between now and Christmas there are hopefully going to be plenty of chances for further snow at all altitudes.
Colin Bell, like cad99uk says 500hpa and 850hpa relate to pressure. 850hpa is roughly the pressure at 1500m, 500 hpa roughly the pressure at 5500m above sea level, so much higher which explains why there can be differences. The chart above is as you spotted based on the GFS operational run. Some of the other charts are based on the ECM model. Hope that helps!
PS. Keep in mind that the GFS charts update a couple of hours ahead of the ensembles.
Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
There's no missing that same brutal low pressure in the channel in GFS 12z...
And a snowy week in the Alps looking to be on the cards... The pattern remains tbe same so the snowfall will major in the south and west, but the snow should hit most places Friday, Sunday and Tuesday as that low piles into the Alps... A brief rise in temperature with the arrival of the snow on Tuesday means it may initially be rain at lower levels, but it looks like a fair amount of snow...
FI? Is looking pretty cold from 03 December to the end of the run...
Local yorkshire weather man Paul Hudson talking about a possible decent snow event early next week as moisture from the south pushes up into Yorkshire and hits the cold air.....
brian
brian Guest
Charts are amazing. Good for the alps, unbelievable for NE Scotland in November.
After all it is free
After all it is free
This is such an awesome thread!
brian
brian Guest
btw, it's worth noting that the 850hPa height moves quite a lot depending on atmospheric conditions. In the middle of a deep low it could be less than 1000m, on top of a high, above 1600m.
Ski the Net with snowHeads
Ski the Net with snowHeads
rob@rar wrote:
This is such an awesome thread!
Is it not?! Largely incomprehensible (to me) mind, but still awesome.
FAQ
Poster: A snowHead
and by Thursday temperatures are dropping again, it looks possible that the precipitation in Austria may coincide with this and so though it will be less heavy will be snowier to a lower level.
. Nice one - except you've got to know where your resort or area is to get the wigglies! Which I don't always know 
Can you do a list along the side like the other wigglies map so I could just look for, say, Courchevel?
Good for the alps, unbelievable for NE Scotland in November. 
