General Model Output Discussion

[derrylynne]

The fax charts are stunning for snow lovers with trofs forming in an unstable flow. I would expect snow in most parts the country over the coming few days - although of course amounts are impossible to predict in this kind of situation. Certainly looks like this is going to be a winter that anyone younger than 30 years will not remember. The thing to remember too is that with the deep cold pool setting up in Europe this will be very hard to shift and could remain there for quite some time before it breaks down.

I would say welcome to a 'proper' winter guys:-)

Edited January 1, 2010 by derrylynne

[phantom]

Sod the slack flow, give me a gale force E,ly. :lol:

Very important Met O 6-15 day forecast coming up today. The reason I say this is we shall find out how many of those ensemble members opt for the HP over the UK bringing very cold surface temps or further N bringing a snowy E,ly. Lets hope its the latter and the forecast mentions heavy snow showers especially in E districts.

Hey Dave you best go check the warning Meto have just issued for Peterborough on Tuesday

[kold weather]

Gosh the runs this morning are quite frankly amazing, its almost like a re-run of Jan 63 jeez!

Anyway the 0z ECM is as expected a rather mammoth upgrade, with a very nice flow indeed and utterly bitter temps as well...the 06z is also quite frankly insane how good it is though I'm not actually all that happy with how it gets us there, lets just say it looks very flabby indeed between 144-168hrs but the broad set-up looks solid enough...

I think I'm going to enjoy looking at the ensembles somehow!

[derrylynne]

Gosh the runs this morning are quite frankly amazing, its almost like a re-run of Jan 63 jeez!

Anyway the 0z ECM is as expected a rather mammoth upgrade, with a very nice flow indeed and utterly bitter temps as well...the 06z is also quite frankly insane how good it is though I'm not actually all that happy with how it gets us there, lets just say it looks very flabby indeed between 144-168hrs but the broad set-up looks solid enough...

I think I'm going to enjoy looking at the ensembles somehow!

I was saying to my wife this morning when looking at the fax charts the last time I saw anything like this was the charts for 1963. Amazing...Given that we have been led to believe that a winter like this is now impossible....

[TEITS]

Hey Dave you best go check the warning Meto have just issued for Peterborough on Tuesday

Those Met O boys are such rampers. :lol:

Encouraging though because its unusual to have an advanced warning this early which suggests high confidence. Looking at the warning areas and this suggests a NNE,ly/NE,ly and based on the models I have seen so far this sounds about right.

Im still going to remain cautious because I really want to see the NE/E,ly at +72. Im always nervous of E,lys in the +120/+144 range.

[Duane S.]

Happy new year to everyone!

After an hour plus of viewing the models/ensembles etc please allow me a little ramp. OMG! :o :o :o

Right, now I've got that out of my system I would just like to say that I was quite surprised to see the ECM quite as good as it was. Not that I believed the 12z but I was concerned it was onto something. I suspect an invigorated northern arm with the PV taking up residence over Greenland may well be how it all ends. BUT that isn't going to happen any time soon and the ECM has now returned a much more realistic (and good looking) chart this morning. We have now all but locked in a cold to very cold period for the next 10-14 days. Quite incredible.

Run of the day for me though has to be the METO 00z. WOW.

[kold weather]

I still wouldn't get too excited about the big easterly idea just yet, would only take a very small change for the main thrust to head southwards, the great thing though is the way the uppers evolve we would still very likely see very cold temps over the UK even if the high ends up being over the UK rather then to our north...

I just can't see any quick way out of this given the large scale evolution, even if it downgrades alot we'd still be in a cold set-up synoptically!

[weather eater]

Another good run from the 06z, with the usual uncertainty beyond the 120 - 144hr mark. Signs of a Scandi high forming on several recent runs, certainly the 06z toys with this idea. While things may look dryish for this side of the country, precipitation is often hard to call, as today testifies, its snowing here now, and while not heavy the frozen surfaces are very conducive to the snow sticking.

[paul tall]

Let us bear in mind, that these charts are on the back of a spell that has already been 16 days and counting for many. I think people need to savour the here now and the near future, this is a once in 20/30 years type of scenario if it plays out. Who'd have thunk it in the climate change days?

[TEITS]

I see 3 options based on the model output.

1. HP settles over the UK resulting in very cold, dry conditions.

2. HP to the N bringing a classic 4-5 days of bitter E,lys with heavy snowfall.

3. HP to the N at first bringing 48/72 hrs of bitter E,lys with heavy snow showers and then HP settling over the UK bringing very cold, dry conditions. Locations such as Kent would experience the heaviest snowfall due to experiencing the bitter E,lys for longer than say NE England.

Based on what I have seen from the models option 3 is currently most likely. When the Met O forecast updates I expect it to say heavy snow showers at first followed by dry and very cold weather.

[tinybill]

I see 3 options based on the model output.

1. HP settles over the UK resulting in very cold, dry conditions.

2. HP to the N bringing a classic 4-5 days of bitter E,lys with heavy snowfall.

3. HP to the N at first bringing 48/72 hrs of bitter E,lys with heavy snow showers and then HP settling over the UK bringing very cold, dry conditions. Locations such as Kent would experience the heaviest snowfall due to experiencing the bitter E,lys for longer than say NE England.

Based on what I have seen from the models option 3 is currently most likely. When the Met O forecast updates I expect it to say heavy snow showers at first followed by dry and very cold weather.

http://www.meteociel.com/modeles/gfs/precipitations/6h.htm

i go along with on option 3 looking at that there could a lot of the white stuff heading our way it could be a 1976 again i was only about 16 then!!!

Edited January 1, 2010 by tinybill

[swfc]

Just a quick point regarding some comments being made regarding 47-63-78 ete.People comparing the current outlook to these specific years should really take a deep breath and relax.T he current outlook is for cold weather showers towards the coast ete,which is now the case.Looking out of the window now its a dry cold winters day ,nothing unusuall really.Models out 2 144 hours may change this but to me nothing spectacular.

[swilliam]

An improvement in the long term from the GEFS ensembles. Looking at the T240 charts many are now showing the Scandi/NUK high with an easterly in the South where as yesterday on the T264 more were not.

This is demonstrated by the mean which, even at this long range, shows the high between Scotland and Norway. The mean T850 has <-10 air over the SE - quite unusual for T240 chart.

So I think we can say that even at this range it is more likley than not the cold will be sustained by building of the High to our North with a v.cold easterly possible in the South.

It seems to me that there are two key features needed for this to happen;

1 the v.cold air needs to reach the Western Med which then causes the European low to deepen significantly and support the high

2 WAA to the West of the UK promoting the growth of the High somewhat west and North and so avoiding the Northern arm of the jet going over the top.

Both these effects can be seen on the ECM and the 06GFS

As a final note I do not know if this has come up before but I see the Meto have changed their long term winter forecast and now give chances of a colder winter to 45% and milder is now only 25%. Seems like nowcasting to me.

Just a quick point regarding some comments being made regarding 47-63-78 ete.People comparing the current outlook to these specific years should really take a deep breath and relax.T he current outlook is for cold weather showers towards the coast ete,which is now the case.Looking out of the window now its a dry cold winters day ,nothing unusuall really.Models out 2 144 hours may change this but to me nothing spectacular.

63 was very dry as well as cold - I think we would say that was quite spectacular.

[Methuselah]

Just a quick point regarding some comments being made regarding 47-63-78 ete.People comparing the current outlook to these specific years should really take a deep breath and relax.T he current outlook is for cold weather showers towards the coast ete,which is now the case.Looking out of the window now its a dry cold winters day ,nothing unusuall really.Models out 2 144 hours may change this but to me nothing spectacular.

Well, this is my 21st winter here in Sneckie; and, this is the first time I've seen thirteen (let alone the expected 20+, unless all the models perform an enormous U-turn!) successive days of almost 100% snowcover at Sea Level???

And, 1963 was a very dry and sunny winter; it was the persistent cold that allowed the snow to lie for so long, and not a succession of blizzards. I think that comparisons to 1981-82 (at least!) are quite fair, TBH... :o

[J10]

I see 3 options based on the model output.

1. HP settles over the UK resulting in very cold, dry conditions.

2. HP to the N bringing a classic 4-5 days of bitter E,lys with heavy snowfall.

3. HP to the N at first bringing 48/72 hrs of bitter E,lys with heavy snow showers and then HP settling over the UK bringing very cold, dry conditions. Locations such as Kent would experience the heaviest snowfall due to experiencing the bitter E,lys for longer than say NE England.

Based on what I have seen from the models option 3 is currently most likely. When the Met O forecast updates I expect it to say heavy snow showers at first followed by dry and very cold weather.

It does seem 3 is the most likely, I just hope we are able to get some snow over the next week or So (some snow showers possible tonight), as it does seem likely to stick around for a while. this snap does seem to remind of 1987, very cold and largely dry for here, but epic further east.

I have done my usual weekly Skiing Forecast Blog

http://forum.netweather.tv/topic/59492-alps-forecast-9/

And these charts show the forecast synoptic patterns for the next 4 days, I think most people would gladly bank the patterns around T+72 to T+96.

[SMU]

Afternoon All-

Well we must be getting good at this- Go back a few years & we would have been very downbeat about yesterdays 12Z ECM, however I think whats been demonstrated is that the plethera of data as well as a wealth of historic model experience can make an eductated guess that a model is not looking correct-

& for all the varification stats we see, the ECM looks to have made a mess of it last night....

Anyway moving on today Im pleased to see that both the ECM 00z & the continued GFS 06z bring the prospect of WIDESPREAD heavy snow, lets be honest the current set up with a gentle NE flow or even a Northerly flow emphasises the sharp cut off zones where ' the rich get richer ' & the snowless areas miss out-

Looking at the radar from last night im sure there are some places sitting with a top up of 20cm of snow-

Even in the 'imby' areas of the SE you can see that a swathe of kent had snow, but move 5 miles inland & its a green backgarden-

Ive seen some comparisons of 1987 being thrown around this morning--- & actually we arent 'that' far away from replicating those synoptic maps & weather perfection-

I think the only ingredient that will be missing is the upper air in terms of depth of cold- remember 1987 had uppers of -17 & thickness around 492 DAM ( at their lowest point in the SE)

looking at the ECM for this chart-

Ive seen that on the other page the upper air is around -14c, calculating the thicknesses ( looking close to the south east with lower heights ) you have around 528 DAM along the 1030 mb contour which using the 0.87 Equation gives approx 504 DAM

Whatever people say or think at this stage in terms of reference to years gone past- 505 DAM into the heart of the UK has happened probably 3 or 4 times in 100 years -

Feb 54, feb 79, Jan 87 & (possibly somewhere each in 63 + 47 > these were snowy winters not perishingly cold winters)

I cant help get just a little more excited as we see the prospect of more widespread snow, thats of course not taking anything away from thos that have snow down -

I note reports of nearly 50cm in quite a few areas already-

all weather fans will be gearing up for the 12z hoping for that epic profile of charts to continue....

Expected return on CET for 1-7 is looking towards -1.5c ......

Steve

Edited January 1, 2010 by Steve Murr

[Frosty.]

The current model output is nothing short of sensational, we have an absolutely bitterly cold week ahead of us, even though it's already cold everywhere with snow around, once the Northerly kicks in at the start of next week it will introduce even colder air which will blast south during monday with frequent and sometimes heavy, prolonged snow showers with drifting, especially in northern and eastern britain. The 6z gfs is a superb run keeping the uk cold or very cold for the entire run with a chance of either an E'ly or another N'ly reload! We really need to enjoy this highly unusual british winter weather while it lasts.

Great post Steve

Edited January 1, 2010 by Frosty039

[Duane S.]

Afternoon All-

Well we must be getting good at this- Go back a few years & we would have been very downbeat about yesterdays 12Z ECM, however I think whats been demonstrated is that the plethera of data as well as a wealth of historic model experience can make an eductated guess that a model is not looking correct-

& for all the varification stats we see, the ECM looks to have made a mess of it last night....

Anyway moving on today Im pleased to see that both the ECM 00z & the continued GFS 06z bring the prospect of WIDESPREAD heavy snow, lets be honest the current set up with a gentle NE flow or even a Northerly flow emphasises the sharp cut off zones where ' the rich get richer ' & the snowless areas miss out-

Looking at the radar from last night im sure there are some places sitting with a top up of 20cm of snow-

Even in the 'imby' areas of the SE you can see that a swathe of kent had snow, but move 5 miles inland & its a green backgarden-

Ive seen some comparisons of 1987 being thrown around this morning--- & actually we arent 'that' far away from replicating those synoptic maps & weather perfection-

I think the only ingredient that will be missing is the upper air in terms of depth of cold- remember 1987 had uppers of -17 & thickness around 492 DAM ( at their lowest point in the SE)

looking at the ECM for this chart-

Ive seen that on the other page the upper air is around -14c, calculating the thicknesses ( looking close to the south east with lower heights ) you have around 528 DAM along the 1030 mb contour which using the 0.87 Equation gives approx 504 DAM

Whatever people say or think at this stage in terms of reference to years gone past- 505 DAM into the heart of the UK has happened probably 3 or 4 times in 100 years -

Feb 54, feb 79, Jan 87 & (possibly somewhere each in 63 + 47 > these were snowy winters not perishingly cold winters)

I cant help get just a little more excited as we see the prospect of more widespread snow, thats of course not taking anything away from thos that have snow down -

I note reports of nearly 50cm in quite a few areas already-

all weather fans will be gearing up for the 12z hoping for that epic profile of charts to continue....

Expected return on CET for 1-7 is looking towards -1.5c ......

Steve

Hi Steve, a great post as per usual. This really does smack to me of a sudden and brutal attack from the NE, aka Jan 1987, occuring sometime in the near future. We are being spoilt at the moment that's for sure and that comes from someone who hasn't had a single snowflake land in his back yard!

[phil nw.]

The current model output is nothing short of sensational, we have an absolutely bitterly cold week ahead of us, even though it's already cold everywhere with snow around, once the Northerly kicks in at the start of next week it will introduce even colder air which will blast south during monday with frequent and sometimes heavy, prolonged snow showers with drifting, especially in northern and eastern britain. The 6z gfs is a superb run keeping the uk cold or very cold for the entire run with a chance of either an E'ly or another N'ly reload! We really need to enjoy this highly unusual british winter weather while it lasts.

Great post Steve

Hi Frosty and A Happy New Year to you and everyone,

Yes agood summary of the output there,mate and by Steve M.

I was relieved to see ECM drop the idea of sinking the block completely on 12z yesterday.

As Steve M was suggesting most areas should have a chance of snowfall in the coming days if the sypnotics develop as seen.

http://www.wetterzentrale.de/pics/Rtavn961.png

Troughs where snow showers cluster together can easily move well inland with the increased instability.

[Frosty.]

Hi Steve, a great post as per usual. This really does smack to me of a sudden and brutal attack from the NE, aka Jan 1987, occuring sometime in the near future. We are being spoilt at the moment that's for sure and that comes from someone who hasn't had a single snowflake land in his back yard!

I thought Jan 1987 was more of an Easterly attack, it was intense cold with maxima of -4 or -5c and lasted almost a week but the rest of the winter was relatively poor, let's hope we don't suffer the same outlook once the current cold spell ends!

[Tom D]

I'm not sure if this is of importance, but the ensembles for Reykjavic air pressure have huge variations after 7 days, with some outputs progging 1040mb and some falling as low as sub-970mb.

http://charts.netweather.tv/ensimages/ens.20100101/06/prmslReyjavic.png

I assume it means the GFS can't decide the location of the high which will affect the scale of this cold spell, ie bringing in easterly winds or sitting right on us with dry, cold and clear conditions.

http://charts.netweather.tv/ensimages/ens.20100101/06/prmslLondon.png

http://charts.netweather.tv/ensimages/ens.20100101/06/prmslAberdeenshire.png

The UK ensembles all seem to trend towards high pressure... interesting to see how this develops over the coming days.

[Frosty.]

Hi Frosty and A Happy New Year to you and everyone,

Yes agood summary of the output there,mate and by Steve M.

I was relieved to see ECM drop the idea of sinking the block completely on 12z yesterday.

As Steve M was suggesting most areas should have a chance of snowfall in the coming days if the sypnotics develop as seen.

http://www.wetterzentrale.de/pics/Rtavn961.png

Troughs where snow showers cluster together can easily move well inland with the increased instability.

Happy New Year phil,

Yes the synoptics are amazing, the 6z gfs is stunning for next week, as is most of the other model output, the GEM 00z looks a bit messy late next week but apart from that it's awesome, and the meto update for next week is superb, even week 2 looks cold and wintry.

Edited January 1, 2010 by Frosty039

[SMU]

Hi Steve, a great post as per usual. This really does smack to me of a sudden and brutal attack from the NE, aka Jan 1987, occuring sometime in the near future. We are being spoilt at the moment that's for sure and that comes from someone who hasn't had a single snowflake land in his back yard!

Thanks for that, in terms of comparisons of actual observed weather I doubt there would be minimal difference- baring a couple of degrees Celcius warmer-

It will put the UK infrastructure under strain if this develops,I think most densely populated areas can get along with on or 2 days of snowcover, however when are talking 5+ with subzero maxima things get a little shakey-

Anyway slighty off topic-

So all eyes towards the radar as well as 15:30 Pm-

Steve

Edited January 1, 2010 by Steve Murr

[nick sussex]

Thanks for that, in terms of comparisons of actual observed weather I doubt there would be minimal difference- baring a couple of degrees Celcius warmer-

It will put the UK infrastructure under strain if this develops,I think most densely populated areas can get along with on or 2 days of snowcover, however when are talking 5+ with subzero maxima things get a little shakey-

Anyway slighty off topic-

So all eyes towards the radar as well as 15:30 Pm-

Steve

Hi Steve

Regarding next week two questions, if for example the gfs 06hrs run verified in terms of night time lows possible under that slack flow am i ramping when i suggest -15 easily achievable in a prone location in England/ Wales with -20 for some parts of the Scottish Glens.

Also in terms of the sinking trough from Scandi is this preferable for it to sink not too far west? have been looking at the interaction between it and the low heading across Iberia.

[doublebarrel]

Hi all happy new year !!

I know its the wrong thread but i dont know if it is of any value to you model watchers, positioning etc ( please forgive my terminology ) but here in Derby i`ve got flakes of snow falling, only odd ones and that many it has now stopped ! dont know if its a help or hinderance !!