[Met Office and BBC Weekly/Monthly Outlooks]

1 hour ago, Updated_Weather said:

I’m talking about the cold weather alert warning as it’s been extended & they said stated this event which could affect London and the S/E has a 30% chance at this stage. As if it did occur could cause disruption.

Ok I’m talking about the weather warning which was issued about 4 hours later

[Met Office and BBC Weekly/Monthly Outlooks]

2 minutes ago, Met4Cast said:

I wouldn't say it's "high". It's a low likelihood weather warning as per the matrix

But yes, certainly high enough to warrant an early warning which is surprising given broader model differences.

Certainly the case as every single automated app (* I refuse to look at BBC Weather but MetO, Accu, WeatherPro, Weather Channel and Apple/Dark Sky) has picked up on it in the last few hours and is showing snow for my location on Sunday for several hours (and into Monday) so clearly sufficient model consensus to warrant the warning.

[Met Office and BBC Weekly/Monthly Outlooks]

26 minutes ago, Updated_Weather said:

They’ve currently placed a 30% of this happening 

Not sure if it's 30% (the text states confidence is very low) but considering the struggle of the models at the moment, I wouldn't expect anything else.

[Met Office and BBC Weekly/Monthly Outlooks]

MetO warning for Sunday's SE feature just out. 2-5cm widely, 10cm in places.

[Model Output Discussion. 3/12/2022. How cold will it get?]

This is what my model blend is producing 

[Model Output Discussion. 3/12/2022. How cold will it get?]

Just now, throwoff said:

The GFS has over the past few years been completely wrong multiple times in winter. It’s a bit like a dog with a bone, once it’s got hold of it sometimes it refuses to let go.

In fact not just winter. We don't have to go back further than summer which the GFS constantly wanted to kill off with fronts sweeping in from the Atlantic, just to then fall in line inside the 3-5 day range. If the GFS would have been right every time it brought the Atlantic in over the last year then most of the country wouldn't have been in a drought!

[Model Output Discussion. 3/12/2022. How cold will it get?]

Great charts this morning. ECM and GFS almost swapped places with the GFS now on its own, but overall more cross-model agreement to keep us cold. Still, nothing is nailed on so best to stick to not taking anything post Sunday for granted.

[Model Output Discussion. 3/12/2022. How cold will it get?]

2 minutes ago, MATTWOLVES said:

Folks we are in a very similar situation here to that of 2018..yes the uppers were colder then but that deep low just like Emma wrecked havoc with the models..there was large uncertainty regarding how far North or if it did indeed even make it through the UK! What actually happened was the storm tracked NW and brought massive snowfalls,especially towards the SW of Ireland. This system also killed the cold snap dead in its tracks. 

So what we could be looking at here is either a huge snowfall for some lucky buggers followed by a quick warm up,or the low misses completely and we stay cold! Or and a big or is that it grinds to a halt and gets pushed back. The ensembles ate now struggling with these scenarios.

So it's a case of huge snowfall and possibly milder or no snow and a staying of the cold!

Do you feel lucky punks....do you wanna take the risk! Deal or no deal? Go for broke and get rich,or end up with nothing!

The choice is yours.....tick tock tick tock 

Folks we are in a very similar situation here to that of 2018..yes the uppers were colder then but that deep low just like Emma wrecked havoc with the models..there was large uncertainty regarding how far North or if it did indeed even make it through the UK! What actually happened was the storm tracked NW and brought massive snowfalls,especially towards the SW of Ireland. This system also killed the cold snap dead in its tracks. 

So what we could be looking at here is either a huge snowfall for some lucky buggers followed by a quick warm up,or the low misses completely and we stay cold! Or and a big or is that it grinds to a halt and gets pushed back. The ensembles ate now struggling with these scenarios.

So it's a case of huge snowfall and possibly milder or no snow and a staying of the cold!

Do you feel lucky punks....do you wanna take the risk! Deal or no deal? Go for broke and get rich,or end up with nothing!

The choice is yours.....tick tock tick tock 

Such an insightful post I had to say it twice

There is of course also the possibility of lots of snow with only a minor incursion of milder air (short change to sleet/rain) and straight back to cold and snow before clearing. Much more rare in the UK than many other places but not unheard of

[Model Output Discussion. 3/12/2022. How cold will it get?]

Wow those are some amazing charts this morning. Yes, as always a lot of caveats if peeking into FI (still sticking with my 4-5 days for now) but it has been a long time since no matter what solution is being churned out by different models and different model runs that all of them end up in a variation of cold/very cold for the foreseeable future. Lots of exciting options re snow, lots of potential for re-load after re-load and cold, cold and more cold.

[Model Output Discussion. 3/12/2022. How cold will it get?]

Beautiful and indeed interesting charts across all runs tonight. Plenty of plausible cold and potentially very snowy options ahead once the cold is properly established.

Further afield the deep lows being churned out are also of interest as very unusual. And yes, let’s keep them far away and then slide

 

[Model Output Discussion. 3/12/2022. How cold will it get?]

3 minutes ago, Nick F said:

Does look very dry away from coasts on the 00z EC out to day 10.

EC and the UKV don't bring any ppn for most from the cold front that drops south on Thursday too. Though GFS does.

But with clear skies likely for many most nights, a widespread hard frost likely. Going to keep the Dec rolling average temp decently below I suspect.

Agreed. However, we all know that once the cold is properly established in the UK surprise snow features pop up at short notice. One of the few occasions where our geographical location is an advantage.

[Model Output Discussion. 3/12/2022. How cold will it get?]

Much more sensible runs across the board this morning, stepping away from things that are just not plausible or possible. Still some uncertainty but if you’re after cold and potentially snowy surprises you couldn’t ask for more!

[Model Output Discussion. 3/12/2022. How cold will it get?]

4 minutes ago, IanT said:

It is always fascinating to see posters queueing up to say that the “…models are struggling…”. I assume this comment is based on the lack of consistency in model output. Whilst there will be only one resolution, at this point multiple evolutions are possible - as reflected by model output..!

Don’t be too quick to conclude that models are struggling because their output is inconsistent. It may be better to recognise that there is still significant uncertainty given the set of starting conditions.

I think that is the point people are trying to make

Struggling = not being able to provide any kind of agreement even at 5/6 days whereas during more common setups we can usually rely on a good few days beyond that.

The models are doing what they’re meant to do, it’s just that the output isn’t helpful to make much of a forecast. That’s not withstanding random hurricane-like low pressure systems being modelled lol.

[Model Output Discussion. 3/12/2022. How cold will it get?]

1 minute ago, damianslaw said:

I'll say it again stick to 96-120hrs tops, and expect swings from the models at timeframes beyond from run to run.  In the reliable becoming cold for all, very cold in the north, with high snow risk from Wednesday onwards becoming widespread and further south in time.

 

Snap

[Model Output Discussion. 3/12/2022. How cold will it get?]

Time to stick to 96-120 hours for now, regardless of model. It’s clear that none of them agree and each one of them throws out different solutions with each run. Tbh it’s no different to what happened in 2010. I went back through some blog posts etc. from back then earlier.

[Model Output Discussion. 3/12/2022. How cold will it get?]

GFS

[Model Output Discussion. 3/12/2022. How cold will it get?]

Just now, Met4Cast said:

The GFS det bombs that low by 20mb in just 4 hours, that would break the world record. Even the strongest tropical cyclones haven't reached that level of bombing. So.. given the GFS det appears to be pushing the boundaries of the laws of physics there I am certain we can bin that idea as not  remotely realistic. 

Funny to see, but no.

The perfect-perfect storm lol. You’re right though… it’s borderline impossible.

[Model Output Discussion. 3/12/2022. How cold will it get?]

1 minute ago, Kentspur said:

Which model is this run by?  

Mainly GFS.

[Model Output Discussion. 3/12/2022. How cold will it get?]

I go out for a few hours and come back to the most bizarre runs I’ve ever seen. Very, very interesting times ahead.

[Model Output Discussion - moving into Winter]

Fully aware of the risk that I may sound like that lady who was in charge about 5 prime ministers ago, I’m just going to say “Nothing has changed” and copy and paste what I said earlier. Substitute GFS for ECM and so on

 

Arguably last night’s ECM wobble in the run up to what looks more and more likely to be a decent and long-ish period of cold weather was one of the most extreme I have ever seen.

But, it underlines further just how much models struggle when having to deal with something out of the ordinary. It happens every time and I don’t think it’s the last wobble we’ve seen over the next few days (or weeks depending on how long the pattern remains). I hope it was a good learning experience for those who aren’t used to it (not through their own fault but simply because these setups/events don’t occur too often). The number one rule is not to take individual model runs as gospel, especially if they make no sense and with cold weather in particular to stop at day 5, sometimes even day 4. For what happens after that period, apply common sense and logic.

[Model Output Discussion - moving into Winter]

Arguably last night’s ECM wobble in the run up to what looks more and more likely to be a decent and long-ish period of cold weather was one of the most extreme I have ever seen.

But, it underlines further just how much models struggle when having to deal with something out of the ordinary. It happens every time and I don’t think it’s the last wobble we’ve seen over the next few days (or weeks depending on how long the pattern remains). I hope it was a good learning experience for those who aren’t used to it (not through their own fault but simply because these setups/events don’t occur too often). The number one rule is not to take individual model runs as gospel, especially if they make no sense and with cold weather in particular to stop at day 5, sometimes even day 4. For what happens after that period, apply common sense and logic.

[Model Output Discussion - moving into Winter]

58 minutes ago, johnny1972 said:

The issue isn't just one run it's also been shown by the GFS but members didn't want to recognise the Gfs as it didn't show what they wanted 

It really isn’t showing on the GFS. 

[Model Output Discussion - moving into Winter]

5 minutes ago, Mark Parsons said:

A small area of low pressure running north to South down the western side or the Eastern side of the UK 

Which, unless I’ve gone blind, isn’t shown anywhere! Instead GFS now randomly produces a deep-ish channel low out of nowhere.

[Model Output Discussion - moving into Winter]

4 minutes ago, Snowman. said:

Unfortunately the GFS archives dont work on meteo that far out. But there was hype but the wheels fell of quickly and further out.

Last Dec was a similar case. Very dramatic and down to the wire, all we can do is wait and see but the trend is not our friend right now. 

 

There certainly was hype but at no point were we anywhere close to the current setup. There was also model agreement across the board around 5 days before that it would most likely be disappointing. Very different to models jumping about and wobbling a bit. They always, always do this with such a huge amount of cold air and high pressure sitting there. In fact 2010 had individual runs up to 3 days before showing all sorts of mad things that would have caused cold rain instead of a foot of snow and -12 temps. Likewise, the “reload” a few weeks later was not shown at all up to 7 days before it happened.

I only ever come here when exciting stuff may be happening but I’ve been doing this for a long time and unless the next few runs stick to what the ECM showed this morning and what the GFS has produced an hour ago, there simply is no trend. Just as there was no trend yesterday - just look back at the doom and gloom after the ECM run and then the hype after the GFS run. 

[Model Output Discussion - moving into Winter]

Just now, Snowman. said:

A greenland doesnt = cold and snow.

Just because the Macro pattern is extremely positive. The UK is a very small target in terms of getting a direct hit cold. And due to the warmer warms and being earlier in the season we often need a perfect Micro pattern to nail UK cold and snow.

A trough being the wrong angle or being a 250 miles too far North/South etc can make a large difference.

I want to highlight this with a chart from Feb 2013.

Incredible convective Easterly just out of reach for much of us in the UK, what could have been a great cold spell but lost to 300 miles SE. It was still cold, but nothing crazy. Comparisons to 2010 and such just heighten expectations which leads to great disappointment. I want cold and snow, but I can only discuss what I see in front of me.

That is all correct but not at the time frame some people are concentrating on. I remember Feb 2013 very well and I think it could be a good idea if you also look at the charts leading up to the non-event.