Model Output Discussion - Colder but how cold and for how long?

[TEITS]

1 hour ago, TillyS said:

This is very true.

It’s the synoptic trend which concerns me more at the moment.

There’s no escaping the fact that the past 48 hours the models, all of the big three anyway, have been backing away somewhat from 1. deeply intense potent northerly and 2. powerful under-cut low across southern Britain.

It may all pep up again but I’m not liking this trend. It usually only means one thing.

If you don't mind me saying your post is inaccurate.

Firstly a potent N,ly has never been really suggested with the average of around -8C upper temps for my location. What has changed these past 72hrs is the ensembles fully agree with how far S the initial N,ly will be. If you recall for my location there was still some scatter as to how far S the N,ly will be on 15th/16th Jan.

I also highlighted how the scatter increased somewhat for the S coast of England. As you can see far less scatter now for E Sussex.

As for the low pressure across S of the UK for next week. This still continues to bring a risk of significant snow but unsurprisingly it appears this may trend further S into France. I however cannot be bothered to focus much on precipitation at the moment as I know its a waste of time and effort. I wish I had a pound for every time "it looks dry" has been posted on this forum over the years!

The reality is a cold spell in the UK often means a drier spell of weather and more settled. Unsettled and still very cold is not something you can expect for our climate. You would be better off living in Tromso (Norway) for such a weather pattern. During the 1963 winter I believe there were many prolonged dry spells inbetween the snowfalls.

Edited January 11 by TEITS
Should of taken more notice of my english teacher

[winterof79]

Just now, frosty ground said:

The PS is my point.

you called 20cm of snow from a setup where the raw data didn’t show 20cm of snow.

today your calling dry from the raw data when we all know that features can and will pop up. Even thou snow is shown of the raw output across the models.

 

Isn't weather just great.

[Man With Beard]

8 minutes ago, Battleground Snow said:

I wish this and that TWO graph wernt available, as they can be confusing for newer members.

They don't show all the members. They show % spreads 

Use the wetter charts or ecmwf own website to see all the members.

You can see it's not an outlier.

To be clear an outlier is a member that totally diverges from all of the other members at that particular point in time.

Eg, the turquoise member 6 on the 23rd of January on this chart

This chart also shows reasonably tight clustering at -4C uppers or below until next Saturday? (This is London so colder further north)

[Mcconnor8]

3 minutes ago, feb1991blizzard said:

Icon an improvement on 6z - powerhouse Northerly.

 

Block does look weaker though so Atlantic may come in sooner on this if it ran on further

[Sweatyman]

2 hours ago, That ECM said:

I guess you are not believing in this?

 This has snow in Scotland and Northern Ireland basically everywhere. South of the m4 basically everywhere and down the north west.

plus the Troughs streamers and showers it wouldn't pick up!! 

[Battleground Snow]

8 minutes ago, IDO said:

Technically, an outlier is when a run is greater or less than three times the standard deviation of the mean.  I assume these are what Meteociel show. 

I believe those charts put the top and bottom 10% of runs outside of the shaded area, but not sure if the exact % number.

If it was 3 times the deviation of the mean wouldn't the op need to show -15 to be an outlier under that definition?

Edited January 11 by Battleground Snow

[Ali1977]

great start from the icon, a much cleaner northerly flow 

[Mike Poole]

13 minutes ago, bluearmy said:

that bloody shortwave next week - @Mike Poole, do you remember me saying we can ignore that when ec popped it up on a day 9 or 10 run cos it won’t verify like that.  And it now looks like it will! 

I’m struggling to remember, Nick, sorry, there are so many posters discussing so many shortwaves at various times and places, it’s a struggle to keep up with which is which!

[Ali1977]

Cold air arrives by Sunday lunchtime on the ICON too

[sheikhy]

Icon at 114 hours is an absolute belter!!colder air aligned more favourably and look at the increase in heights over the pole!!!brilliant!! @feb1991blizzard

[booferking]

2 minutes ago, Mcconnor8 said:

Block does look weaker though so Atlantic may come in sooner on this if it ran on further

Much better run clean northerly and that bluge is gone and low esb sliding better.

[Kasim Awan]

13 minutes ago, frosty ground said:

The PS is my point.

you called 20cm of snow from a setup where the raw data didn’t show 20cm of snow.

today your calling dry from the raw data when we all know that features can and will pop up. Even thou snow is shown of the raw output across the models.

 

You are spinning my objective analysis of output into a forecast. And you have just contradicted yourself saying I should have used raw data then in the next paragraph say raw output can't be trusted. The 20cm was objective analysis of one model run and was roughly 4x the base instability values than this Monday which gave 5cm max.

I am not an amateur. I said 2-7cm in Kent Monday when most models had 1cm max. Thanks, Kasim.

Edited January 11 by Kasim Awan

[Lukesluckybunch]

2 minutes ago, sheikhy said:

Icon at 114 hours is an absolute belter!!colder air aligned more favourably and look at the increase in heights over the pole!!!brilliant!! @feb1991blizzard

We seem to have lost that big bulge..hopefully models wil make less of that shortwave going forward!

[Northern Lurker]

2 minutes ago, TEITS said:

You would be better placed living in Tromso (Norway) for such a weather pattern.

Indeed, preferably with no access to the internet! Having watched the current pattern evolve since late December it's remarkable how well the models have counted down to 15th January. It's anyone's guess how long it lasts or how much snow there will be, but you can't have snow without the cold uppers... You can bet your bottom dollar that if there was a lot of precipitation shown but uppers were marginal the same individuals would be saying that there was no hope etc. 

[Liam J]

Confused at people saying the block over Greenland doesn’t look strong…. This looks good to me with a clean northerly! Better than the 0z run imo with heights punching well into the polar regions. 

[TSNWK]

1 minute ago, sheikhy said:

Icon at 114 hours is an absolute belter!!colder air aligned more favourably and look at the increase in heights over the pole!!!brilliant!! @feb1991blizzard

I'm so confused as scroll through on phone is icon upgrade or downgrade? 

[bradymk]

8 minutes ago, Mcconnor8 said:

Block does look weaker though so Atlantic may come in sooner on this if it ran on further

It does but I think it’s a better run (up to what we can see anyway). It is slightly weaker and further west / north west, but we have less influence from the surface high, a better flow at +120 and a ridge pushing north up through the NE US coast which could be important down the line.

Edited January 11 by bradymk

[seabreeze86]

The APERGE still rock solid in bringing a much cleaner northerly been consistent for a while now 

[Ali1977]

Just now, TSNWK said:

I'm so confused as scroll through on phone is icon upgrade or downgrade? 

Upgrade

[Paul33]

1 hour ago, Nick123 said:

People are just sayin' what the models are saying problem is folk don't like it lol

......or "People are just sayin' how they are interpreting the models - problem is folk don't like it lol" ?

[AltonMatthew]

Just now, Paul said:

How joyous it must be for people to turn up here in the morning, hoping to read up on the model output to find a(nother) circular argument doing the rounds again. Can we move on now, please.

[Lukesluckybunch]

3 minutes ago, Liam J said:

Confused at people saying the block over Greenland doesn’t look strong…. This looks good to me with a clean northerly! Better than the 0z run imo with heights punching well into the polar regions. 

Mild sector getting squeezed out on the 6z

[Man With Beard]

Here's a Meteociel look at how the ECM mean has done for the famed 15th January, comparing the mean at D10 with this morning's op, which is now D4:

 

That's absolutely brilliant.

[bluearmy]

7 minutes ago, Mike Poole said:

I’m struggling to remember, Nick, sorry, there are so many posters discussing so many shortwaves at various times and places, it’s a struggle to keep up with which is which!

True  enough !

Just making the point I guess that whatever the worst feature that’s likely to reduce the cold for us seems to verify (or it just seems that way)

We know that shortwaves pop up as the modelling gets within days 8/9

this one could just as easily have ridden the trough and come up the channel as we’ve sometimes seen in the past. Coupled with the detached ridge dropping se (suspect there is a connection),we manage to cut off the cold before its entrenched enough to guarantee snowfall from the Atlantic incursions 

hey ho 

still plenty to be watching 

[kate1]

34 minutes ago, Kasim Awan said:

No mate, I was saying what the operations were showing which not a prediction of what is going to happen. It's too early to make any prediction so my posts are just speculation / objective analysis of conditions not definitive forecast anyone with any inkling in meteorology would know that. So was the 20cm based on one ecm run was not any sort of prediction.

I predicted 2-7cm for West Kent during the event just gone.

To be fair at my location in West Kent we would have had that had it settled - snowfall was quite intense for a while. Presumably that was because the ground was so sodden from previous rainfalls but that won’t be a problem next week.