Model output discussion - here comes the beast!

[stewfox 4,369]

53 minutes ago, SizzlingHeat said:

The coldest uppers seem to be always post 144. The Easterly seems a lot slacker with more shortwaves causing a less clean flow. Not sure we will be looking at -15 or more uppers any more. Always seems to be delayed by 6 hours then another 6 hours and so on. 

Get the misses to make you a cup of tea and a sandwich ,6 hours will go in no time,,,, it is coming

Only -14c uppers end of February

 

[Jon Snow 80,643]

I've seen enough model output to convince me next week and probably the following week is going to be the most wintry spell since 2010..expect days and days  more magnificent output.. The Siberian Express is on the way!

[Ice Day 7,151]

Short ensembles go cold from 96 hours, with the real cold getting in from around 132.

[Weathizard 4,915]

1 minute ago, Ice Day said:

Short ensembles go cold from 96 hours, with the real cold getting in from around 132.

Proves just how bad the GFS is at picking up precipitation, barely a single spike on any ensemble... no way would London be that dry.

Edited February 20, 2018 by Weathizard

[Captain Jack Sparrow 11]

30 minutes ago, johnholmes said:

Looking, or rather skimming through the last x pages from late afternoon, reiterates why I do not spend too much time in here.

Some of you for goodness sake have a walk outside,  watch the tellie, talk to a real person away from the pc. What you are watching is the weather models trying and slowly but surely, as they always do, come to a concensus about what is happening. Quite why folk worry about T+240 and beyond when most predictions by the models at that range are highly prone to change is beyond me. Deep cold is 85-90% likely to occur, it has never really been sensibly predicted by any of the more serious posters assessing the various outputs to occur before 23-25 February. That was two weeks out. Now within a week of the second date that is being refined to more like 25-26, so what? Get a grip and become realistic, they are models created by humans, are you perfect?

end of jh rant.

here is the latest link to NOAA 500 mb anomaly charts. This level, approximately 18,000 ft is far easier to predict than the surface, these are mean charts, but they are about 70-75% close to what occurs in about 80% of cases. Yes they are wrong at times but not often.

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

To me, using them every day for about 7 years and during the winter for 10 years or so I cannot recall seeing charts showing any more solid northern blocking for the time scale they are showing, this for at least 3-4 days. That includes the deep cold much of the country had in late Novemeber-December 2010.

 

Hi John

You are one of, or maybe the most circumspect poster on here and your anomaly input is highly valued. So don’t get stressed out with what others are posting, or which charts they are viewing and their interpretations of such. You have been telling people for years not to get hung up on individual runs, but this is what many people on here do for fun. Let them have their fun! Each to their own, there is no right way to do this as the weather will remain as unpredictable as ever. That unpredictability  is what engages us all.

[ITSY 1,955]

Note that across the ensembles there are multiple lows or small features running across central southern england (EA, Mids, SE, S) on Tuesday. Multiple small spikes on the charts showing. Just proves - get the cold in, get the wind blowing from the East, and in a flow like this disturbances will start to appear. I’ve done a Murr and my battery is now at a mere 4% so will have to return tomorrow. On that note, night all! 

Edit - see emerging precip for cambridge as an example, hardly a coastal town 

Edited February 20, 2018 by ITSY

[Mucka 16,491]

The Control is truly epic, stays cold throughout and throws in a blizzard for the SE in deep FI (when it would probably already be buried )

Fingers crossed we get something so memorable

[markw2680 2,758]

50 minutes ago, markw2680 said:

Don’t shoot me down as I am a real amateur just an enthusiast but it does seem like the real cold blast is getting delayed every day so not really getting closer as such (the real cold that is) the longer it takes to get here the shorter it will be as the breakdown etc will not get further away so will end up been just a blast. Hope I’m very wrong but it’s a feeling that I have tbh

Well I feel a right plank now I came on here and saw a few posts and pics of delaying cold and all that and then put a comment on without actually having a proper look for myself. Well that will teach me to look in future as well I couldn’t be more wrong. Oh well live and learn I suppose, back to the models and let’s get the cold in.....?

Think I should just go back to the background lol

[kold weather 11,956]

1 minute ago, Weathizard said:

Proves just how bad the GFS is at picking up precipitation, barely a single spike on any ensemble... no way would London be that dry.

Also that shows that the GFS op run was one of the slower runs to push the cold air westwards, plenty are a good 12hrs quicker. Personally I think the 18z timeframe is more realistic and goes along with the ECM which has been almost constant in its arrival overnight of 25th and early 26th.

[Pixel 714]

8 minutes ago, MattStoke said:

Apologies for the off topic post but, this is very interesting from the pros (and exciting for lovers of cold and snow) - https://weathertrending.com/2018/02/20/bitter-quickchat-next-weeks-extreme-cold/

This is a good find ^ thank you Matt

yes.. we are going to get some serious cold... but will there be moisture picked up to fall as snow IMBY? - It looks likely but how any model can forecast that precisely at this range 5-7 days out is anyone's 'guess' and that includes the 'models' as they are bound by their data input based on previous scenarios. The SSW warming, the resultant reverse of weather flow from West to East to East to West is interesting but when one takes into account the extreme amount of cold modelled combined with the amount of relatively warm water it has to pass over before it hits the eastern side of our little island (UK) the outcome is pretty much only predictable t-48 or less. Prob why 'some' are saying it's only going to cold and dry..

Enjoy... esp as any warm fronts try to move in from the south to wrestle with the beast from the east.

Salt for the driveway, good tread on tires and logs for the wood burner bought + camera at the ready.. oh and some mulled wine ingredients too 

Please don't forget to check on elderly or vulnerable neighbours

attached last snow here on 10th Dec 2017 was very pretty:

[inghams85 1,011]

7 minutes ago, kold weather said:

Also that shows that the GFS op run was one of the slower runs to push the cold air westwards, plenty are a good 12hrs quicker. Personally I think the 18z timeframe is more realistic and goes along with the ECM which has been almost constant in its arrival overnight of 25th and early 26th.

There are a surprising amount that bring in deep cold mid Sunday tbh!! I wouldn't rule out quicker incoming cold at all

[inghams85 1,011]

1 minute ago, Pixel said:

This is a good find ^ thank you Matt

yes.. we are going to get some serious cold... but will there be moisture picked up to fall as snow IMBY? - It looks likely but how any model can forecast that precisely at this range 5-7 days out is anyone's 'guess' and that includes the 'models' as they are bound by their data input based on previous scenarios. The SSW warming, the resultant reverse of weather flow from West to East to East to West is interesting but when one takes into account the extreme amount of cold modelled combined with the amount of relatively warm water it has to pass over before it hits the eastern side of our little island (UK) the outcome is pretty much only predictable t-48 or less. Prob why 'some' are saying it's only going to cold and dry..

Enjoy... esp as any warm fronts try to move in from the south to wrestle with the beast from the east.

Salt for the driveway, good tread on tires and logs for the wood burner bought + camera at the ready.. oh and some mulled wine ingredients too 

Please don't forget to check on elderly or vulnerable neighbours

attached last snow here on 10th Dec 2017 was very pretty:

In December 2010 with the Easterly it was around 48-54 hours away before models like the Euro4 picked up a signal for 15-30cm's. Don't even bother I'd say tomorrow evening have Euro4 on refresh to pick anything up from Friday onwards even if it's flurries Friday Saturday for now

[Quicksilver1989 5,890]

Interestingly quite a few ensemble members have a few little low pressure features early next week in the cold flow like the 12z ECM, keep an eye out for them in future runs .

One rogue ensemble member allows the deep cold pool to miss the UK completely.. think that went off on one haha! Some really bitter ensemble members in there though and as a few have mentioned, quite a substantial number have cold making inroads midday Sunday.

Hope it continues tomorrow! Night all 

[Mucka 16,491]

A big picture look at the ensembles today, comparing 00z and 18z for Central England.

 

00z have peak cold mean 850's at perhaps 1c colder than 18z

00z passes the -10 mark at around midday on the 25th, the 18z around mid morning the 26th

00z rises above -10 line First thing March 1st, 18z 2nd of March midday

00z rises above -5 on 4th March, 18z on 6th of March

00z has in sub -5 850's continuously for around 168 hours, 18z for around 228 hours

00z has in sub -10 850's for around 86 hours, 18z for around 98 hours

 

Swings and roundabouts basically but you could say the trend today was to bring the true cold in a little later but sustain it for longer and to delay any breakdown.

ECM not really any hint of warm up until March 5th at earliest and even then it is very dubious and in line with the ensembles attempting to return to climatological norms

Edited February 21, 2018 by Mucka

[inghams85 1,011]

Potentially this could be extremely snowy. Showers. Then lows from the East. Then Showers again and then sliders/North Easterly showers. Easy right?

[The Eagle 1,947]

18z NMM 1km resi to Sunday evening

[SLEETY 5,571]

not long now that this easterly will be coming in to the much more reliable time frame,if it's going to go wrong then it will have to show up in the next series of runs later today,get through that and we are almost there.once it get to 72 hours away, the high res models will be able to pick up the  areas which will first get to see the snow.

though eventually most will have seen falling and lying snow 

 

incredibly exciting times ahead and even historic .let the fun and games begin soon.

Edited February 21, 2018 by SLEETY

[Allseasons-si 24,571]

What a great set of model outputs again today,truely epic across the board and you don't see charts like this every winter so take note

i am going to drift over to the strat thread shortly to post this,the JMA has had to upgrade the chart from -30hpa to -20hpa because of the significant second warming,now that hasn't happened before or i haven't noticed it before but it is truely remarkable

it will be interesting to see the 10hpa in the morning

 

 

[CreweCold 27,610]

The ICON has picked up on that disturbance running E-W...It has it further N than ECM

Just like the ECM, the coldest uppers are ushered in behind this feature...

Some eye watering uppers following on behind it

Edited February 21, 2018 by CreweCold

[Mucka 16,491]

@CreweCold

Embedded troughs definitely look likely which should give some more organised snow/shower bands getting well inland. 

It would certainly make a nice change for NW England to get snow off an Easterly.

Output off to a great start anyway.

GEM has better alignment than its previous run and again withe squiggly lines - I love to get technical,

Edited February 21, 2018 by Mucka

[CreweCold 27,610]

Just now, Mucka said:

@CreweCold

Embedded troughs definitely look likely which should give some more organised snow/shower bands getting well inland. 

It would certainly make a nice change for NW England to get snow off an Easterly.

Output off to a great start anyway.

Indeed...

What I think we're seeing is the initial thrust go mostly through France, but the second wave of cold comes through at a more N'ly latitude. You can see this on the UKMO too. I think that is why people are seeing the output shift back a bit

[CreweCold 27,610]

That patch of -28 uppers Over NW Russia is the cold pool which is thrust towards the UK through Scandi as the HP pivots and ejects the colder uppers and associated instability with it

[Mucka 16,491]

Certainly nothing wrong with UKMO which gets the cold in pretty much on schedule.

If I were being hypercritical I would still want the high a bit further North a la previous GFS runs.

I will just edit in that UKMO is still a dream run in the grand scheme of things, just nitpicking.

UKMO is quicker with the cold than GFS 00z though.

 

GEM is an absolute beauty this morning.

GFS is probably the least impressive chart at 144 this morning though still good in its own right

Edited February 21, 2018 by Mucka

[MattStoke 6,415]

The real cold reaching the UK early Monday on the GFS. So we’re now only 5 days away.

[CreweCold 27,610]

The GFS has the little disturbance ala ICON forming off S tip of Norway at 144