Model output discussion - proper cold spell inbound?

[winterof79]

It is pay back time for Canada,now we have our own PV and a bit of reverse thrust.This is for the never ending pile of muck you've sent us for what seems like an eternity.

Have it my San....

Edited February 13, 2018 by winterof79

[Banbury]

2 minutes ago, ptow said:

Yes, its a long way off but to clarify, and in the interest of balance, for anyone that is confused at present based on the evidence we are more likely to be looking toward a standard cold spell rather than anything any of us would call spectacular.

I disagree the 0z ( GFS ) was stunning and far from standard.................unless you have a different level of expectation as to what is spectacular , make no bones about it the  0z was stunning.

Unless you have different data ?

[Gustywind]

3 minutes ago, ptow said:

Yes, its a long way off but to clarify, and in the interest of balance, for anyone that is confused at present based on the evidence we are more likely to be looking toward a standard cold spell rather than anything any of us would call spectacular.

In terms of temperatures the Feb 05 spell which took place in the last week of Feb is the closest comparison I can think of. 

If temps are same as back then, some will be disappointed. Here in Birmingham we averaged temps of 4-5c in sunshine on the coldest days (when 850s were circa -10), climbing to 6c when 850s rose back up to -6 or so towards the end of the week.

Those temps were in full sunshine I should add. It was quite a snowy week but snow struggled to settle in daytime hours due to the high temps and sunshine, so accumulations only took place at night. 

That was a milder winter than this one though and Europe had been very mild in the run up.

[frosty ground]

4 minutes ago, Gustywind said:

In terms of temperatures the Feb 05 spell which took place in the last week of Feb is the closest comparison I can think of. 

If temps are same as back then, some will be disappointed. Here in Birmingham we averaged temps of 4-5c in sunshine on the coldest days (when 850s were circa -10), climbing to 6c when 850s rose back up to -6 or so towards the end of the week.

Those temps were in full sunshine I should add. It was quite a snowy week but snow struggled to settle in daytime hours due to the high temps and sunshine, so accumulations only took place at night. 

That was a milder winter than this one though and Europe had been very mild in the run up.

Fed 05 gave me over a foot of snow, but yes the temps where a little higher than one would expect, this was in part due to some warm air getting mixed in the flow from the south east.



The issue was the surface flow rather than the uppers.

 

Edited February 13, 2018 by frosty ground

[ptow]

3 minutes ago, Banbury said:

I disagree the 0z ( GFS ) was stunning and far from standard.................unless you have a different level of expectation as to what is spectacular , make no bones about it the  0z was stunning.

Unless you have different data ?

No, I was purely going by the 0-3 day maxes. Not sure if that was from the 0z or the 6z tbh. Stunning for me would be something yielding sub zero maxes and I am talking lower than -1.

I haven't seen any data to suggest deep cold being likely

 

 

[ptow]

4 minutes ago, Gustywind said:

In terms of temperatures the Feb 05 spell which took place in the last week of Feb is the closest comparison I can think of. 

If temps are same as back then, some will be disappointed. Here in Birmingham we averaged temps of 4-5c in sunshine on the coldest days (when 850s were circa -10), climbing to 6c when 850s rose back up to -6 or so towards the end of the week.

Those temps were in full sunshine I should add. It was quite a snowy week but snow struggled to settle in daytime hours due to the high temps and sunshine, so accumulations only took place at night. 

That was a milder winter than this one though and Europe had been very mild in the run up.

Yes, I remember it well, I was in Brum myself at the time. There were plenty of snow showers but didn't really settle and as you say pleasant in the sun

[Gustywind]

1 minute ago, frosty ground said:

Fed 05 gave me over a foot of snow, but yes the temps where a little higher than one would expect, this was in part due to some warm air getting mixed in the flow from the south east.

Yes it was better up north, think the North York moors got a fair bit also. Think the SE corner had a snow event at the end of the spell also when some very cold uppers got into the mix.

I do remember though a lot of moaning from southerners, particularly in the East about showers falling as rain or sleet that week! 

[karlos1983]

Control run could be a jaw dropper, plenty of waa heading up to the pole to aid Blocking!

Edited February 13, 2018 by karlos1983

[Catacol]

19 minutes ago, Timmytour said:

Last week the GFS has the far reaches of FI showing snow for most of us next tuesday.  Something it seemed to drop dropp in the 200-264.range

Won't have been the first time it has proved more accurate from further out than from the medium range. IF it modeeling it accurately now of course!

It’s an interesting one this - maybe @SnowBallz could add some flesh? True to say that GFS was solid for at least 5 runs in a row (I stopped counting at 5) when next week was at 320h plus range. High pressure to the north with low pressure to the south. It then dropped the idea in the mid range, as did ECM for a time, before picking it back up again as the ssw occurred.

Not the first time that extended modelling has picked up something, dropped, and then come back with it. Maybe it feels more common than is actually the case.... don’t know cos I don’t keep records about this... but it feels as though it is not that uncommon.

Is there something in the model algorithms that puts greater emphasis on different factors when looking at extended range than when the clock moves into medium range? Do they function in exactly the same way at all time scales? We know resolution improves at 72h (at least that usd to be the high resolution point - is it further out now?) but is there anything we can learn about medium v extended?

We are approaching crunch time now - the general pattern looked great a good few days ago now... but now we need a bit of luck to kick in. From around tomorrow we may be able to see whether we are set for dry and cold, or snowy and cold - this relationship likely to wax and wane throughout the cold spell according to orientation and block movement... but I think we will be unlucky if at least once in the spell we don’t get alignment of the block and frontal system development to bring a snow event of substance. Having said that - scars from March 2013 are still raw as nothing arrived here from that setup... so there is no guarantee of anything when it comes to weather watching.

 

 

[frosty ground]

Had that been the Operation run 

[The Beast From The East]

1 hour ago, Steve Murr said:

Morning All

Today is a record breaker ( I can hear Roy Castle !!! )

 

The longwave patter is beginning to become a little clearer now with what we observed from day 1 - the migrating Canadian High migrating east before launching itself NE towards Scandi-

There appears to be an interim period of stability whilst located over scandi ( Days 8-11/12 ) before retrograding against the flow to Greenland-

With that in mind from Day 8 its going to be cold- With the level of cold decided by how much lattitude we get & also how much energy we can see returning under the high - 

Worst case scenario appears to be a light continental flow with below ave temps, best case scenario - scenes like 1991/1987 ---

So with that in mind we now need to track the evolution in the 168-192 window -

The ECM gets to the maximum really

Notice the core of the High is centred North of Scandi - Thats where were aiming for..

So its a case of round 1 ( hopefully ) followed by round 2 with a whopping GH --

S

 

This link is for the classic weekly 1991 February forcast by Ian M on the BBC.

Now my question to anyone. This was for the week from the 6th Feb. We had daytime temps of can you believe -5 or lower and that wasn't windchill either. 

Could we still ever get these type of temps if we get the perfect set up or similar to the above set up come the last week of Feb into early part of March going by what the models are hinting at? 

Many Thanks.. .. ?

[Ice Day]

Control at 240, just WOW (I've said that a lot in the last couple of days!) 

 

[Weathizard]

Archive this, probably the best day 10 mean you can ever wish to see

[frosty ground]

Looked at the first 10 GEFS and at least 3 of them draw up a south easterly flow from Greece...... Feb 2005 ish

 

[Ice Day]

Out to 264 and it's absolutely stunning   -12' across the eastern half of the UK

 

 

[Banbury]

Stunning control

[frosty ground]

An epic Snow storm (marginal near the core) But wow what a run that is. (okay no more individual perbs from me)

[Ice Day]

And at 276 the -12's are across to Ireland, this is really incredible output at the moment and everyone is getting in on the act on this run.

 

[BLAST FROM THE PAST]

6 minutes ago, TheBeastFromTheEAST said:

This link is for the classic weekly 1991 February forcast by Ian M on the BBC.

Now my question to anyone. This was for the week from the 6th Feb. We had daytime temps of can you believe -5 or lower and that wasn't windchill either. 

Could we still ever get these type of temps if we get the perfect set up or similar to the above set up come the last week of Feb into early part of March going by what the models are hinting at? 

Many Thanks.. .. ?

Well seeing as Feb 91 was exceptional....possibly not.  But if todays runs are correct it’s going to give it a darn good go.  

 

BFTP

[karlos1983]

Control run brings what would be a snow event to remember for the south, what I wouldn't give for that to verify 

 

[jvenge]

Placement of that HP around the UK is so messy on the GEFS 6z. Even at T144 it can go in so many different directions.

[shaky]

1 minute ago, jvenge said:

Placement of that HP around the UK is so messy on the GEFS 6z. Even at T144 it can go in so many different directions.

Good stuff i suppose could bring in cold later but could also bring in cold earlier!lets see where 12z goes!!

[karlos1983]

Well well well, many purbs want an arrival of cold in a weeks time! things appear to be gathering a pace!

and then there is the ECM ens, also trending colder 

EDIT: in fact that's the best set we've seen yet! hardly any mild runs! Compare it to yesterday’s 12z, it's night and day

Edited February 13, 2018 by karlos1983

[SMU]

13 minutes ago, Weathizard said:

Archive this, probably the best day 10 mean you can ever wish to see

but not spectacular lol....

Its about as good as Mean as you could ever get once you filter out the odd rogue run...

Edited February 13, 2018 by Steve Murr

[Ice Day]

The 6z mean at 228, 252 and 276....jawdropping