Model Output Discussion - Staying cold into the new year

[Alexis]

The High lasts about 4 days, so tropical or not, it's gone soon anyway!

[phil nw.]

37 minutes ago, frosty ground said:

Now my memory is not what it used to be but I do not remember any forecast showing ice days for London’s with maybe the exception of one or maybe two Operational Runs.

the only watering down i have seen are peoples OTT expectations and this only feeds the usual “I’m sorry to say but” gang that constantly wants to police what people expect 

Yes the London combined temperature ensembles for one have been pretty consistent.Compare the graph from the 22/12 so it's been pretty much what we have seen up to now.Today's projections along side.

Running steady between 2-4c max' since Christmas,actually today looks the coldest so far in this spell which is now a week long already.

Note the uncertainty towards the end where we have a few mild runs skewing the trend up a little.GFS 0z operational a mild outlier right at the end.

Edited December 31, 2020 by phil nw.

[northwestsnow]

Bloody Greeks and Turks 

Still managing to chicken up our cold spells lol!!

Banter aside, I'm hoping UKMO has this.

Eyes down for the 12zs

[Jason M]

8 minutes ago, Daniel* said:

Don’t you realise the air travels 1,200 miles? Theres plenty of distance for that air to cool It has no semblance to origins, and at present I think models aren’t capturing that. You’d think some people think it’s going to be a tropical easterly.

There was also evidently modification in early Feb 2009 very wintry for most of country the Siberian link was severed very quickly. 

The airmass will become modified and whilst it’s true to say a tropical origin airmass won’t feel tropical in the part of the atmosphere where we live it can and will often retain some of its characteristics higher up. Thereby you can get rain with temps that should support snow because of a warmer layer higher up. Freezing rain is a good example of this. The models will be factoring these things in but at this point whether they are right or not is unknown. I suspect it will be mostly wet but I’d not be surprised to see some snow mixed in at times and maybe even some proper bursts of wet snow. Maybe higher ground to the NW of London might get a wet covering but for most it’s just wet and miserable in all likelihood unless things change.

[Cloud 10]

A few posts about model verification on the last few pages,and it seems not much has changed over the last few years with the ECM still top followed by UKMO and the GEM (CMC) and then GFS.

 

NCEP EMC Global Model Verification

WWW.EMC.NCEP.NOAA.GOV

 

[Frosty.]

Ach well, the ECM 0z ensemble mean is trending colder, indeed it’s colder longer term than I’ve seen it so far !!!..so that’s another tick in the box then init!!!!! ! 

Quote

I’m a happy bunny...love these charts! ️ 

 

Happy New Year  

Edited December 31, 2020 by Jon Snow

[sheikhy]

9 minutes ago, northwestsnow said:

Bloody Greeks and Turks 

Still managing to chicken up our cold spells lol!!

Banter aside, I'm hoping UKMO has this.

Eyes down for the 12zs

We will know by this evening whether ukmo is correct or not!!differences are quite early at 72 to 96 hours!!!the ukmo might be colder but high is further south slightly so not sure how much precipitation there would be!!!gfs will probably give us a clue!!

[chris55]

Day five UKMO vs ECM

subtle differences,

UKMO with a more north east flow (avoiding the main pick up of that less cold air).

ECM flatter from the east allowing the southerly push of air into the easterly mix.

 

Will be interesting to see how the 12z Euros handle this period. 
 

More like UKMO and snow is possible I would think (though can’t see dew points etc) 

More like ECM, rain more likely for most. 
 

UKMO

ECM

 

Edited December 31, 2020 by chris55

[bluearmy]

37 minutes ago, Daniel* said:

Don’t you realise the air travels 1,200 miles? Theres plenty of distance for that air to cool It has no semblance to origins, and at present I think models aren’t capturing that. You’d think some people think it’s going to be a tropical easterly.

There was also evidently modification in early Feb 2009 very wintry for most of country the Siberian link was severed very quickly. 

Also the thicknesses in 2009 were below 520 dam. Next week they are 525/530 .....

[winterof79]

Crikey you'd think it was warming up for days reading this lot. 

Have the Beeb mentioned how long for, if they get it correct. 

Blink and you will miss it. 

[Updated_Weather]

1 minute ago, winterof79 said:

Crikey you'd think it was warming up for days reading this lot. 

Have the Beeb mentioned how long for, if they get it correct. 

Blink and you will miss it. 

BBC suggest a STONKING high of 4c for me in Essex all the way through til 13th

 

let’s see what 12z say coming up soon!

[bluearmy]

Methinks some of you are missing the point .......’get the cold in and the snow will follow’

so we’ve got the cold in 

the forecast temps quoted above show that 

but the vast majority of the precip over the next  week (ignoring the disturbances before the weekend and the odd surprise before the higher Dp’s arrive which away from the high ground and Scots amount to little) is going to be rain.  it’s just frustration from many posters that the great looking charts are going to deliver very little and they now have to go through some v cold rain before they can have another ticket to the raffle. 
 

of course some have had a decent snowfall this week and should be grateful for it but as was trailed as the week began, the majority will not. 

Edited December 31, 2020 by Paul

[winterof79]

5 minutes ago, bluearmy said:

Methinks some of you are missing the point .......’get the cold in and the snow will follow’

so we’ve got the cold in 

the forecast temps quoted above show that 

but the vast majority of the precip over the next  week (ignoring the disturbances before the weekend and the odd surprise before the higher Dp’s arrive which away from the high ground and Scots amount to little) is going to be rain.  it’s just frustration from many posters that the great looking charts are going to deliver very little and they now have to go through some v cold rain before they can have another ticket to the raffle. 
 

of course some have had a decent snowfall this week and should be grateful for it but as was trailed as the week began, the majority will not. 
 

all the above ignores the Scots who, as they keep telling us, live in a different country! 

My question is how long are the higher DPs forecast? 

Doesn't look longer than 24 hrs before a  colder airmass mixes from the NW. 

[Northernsnow]

So from what I’m seeing it looks like a very slight relaxation of the cold. But definitely nothing mild showing on the models whatsoever. Let’s hope the ukmo run from this morning is on the money. But even the gfs & ecm aren’t particularly that bad. So from my very little knowledge I have compared to many on here it a slight relaxation of cold next week before we then head back into the freezer with snow opportunity’s for many of us what’s not to like definitely a far cry from the last few winters. 

[bluearmy]

4 minutes ago, winterof79 said:

My question is how long are the higher DPs forecast? 

Doesn't look longer than 24 hrs before a  colder airmass mixes from the NW. 

I posted the Luton Dp’s a while back - I think it’s around three days 

[winterof79]

20 minutes ago, Northernsnow said:

So from what I’m seeing it looks like a very slight relaxation of the cold. But definitely nothing mild showing on the models whatsoever. Let’s hope the ukmo run from this morning is on the money. But even the gfs & ecm aren’t particularly that bad. So from my very little knowledge I have compared to many on here it a slight relaxation of cold next week before we then head back into the freezer with snow opportunity’s for many of us what’s not to like definitely a far cry from the last few winters

Good Post NS. 

Edited December 31, 2020 by winterof79

[Scandinavian High.]

Could it be case that we see overnight showers tuning more wintery next week and as day goes on turn more rain sleet.

[edo]

I think sometimes it's just hard that this model thread covers such a wide area and it's only natural that people view the charts from their own perspective. I have long since learned to use the ignore button and to look at people's locations to ensure I understand the perspective they are coming from. There are some brilliant posts in here and it would be nice if everyone could just be a bit more tolerant of others views. Nick Sussex and John Holmes, Scott Ingham a great new addition, S Murr has a brilliant way of teaching with his posts and I find Crewecold very informative when he's not offering up testicles. In the Scottish thread we are blessed with several brilliant contributors. I have also enjoyed learning about the differences in sea temps and the impact of modification and thanks to Blue army for putting more meat on the bones to his views...

I think it is so important that it looks like rain or its boom is backed up with some explanation. 

 

My own very novice view is that we remain on the cusp of a great spell but next week will prove similar to this with maybe a bit more punch particularly for Scotland as we see uppers potentially 2c lower than this spell just experienced and also indications we get that slightly more N/E flow and the air does appear to have a bit of bite from that direction if not the full bite we would normally expect to see. 

I 

Edited December 31, 2020 by edo

[Cold Winter Night]

1 hour ago, Daniel* said:

Don’t you realise the air travels 1,200 miles? Theres plenty of distance for that air to cool It has no semblance to origins, and at present I think models aren’t capturing that. You’d think some people think it’s going to be a tropical easterly.

There was also evidently modification in early Feb 2009 very wintry for most of country the Siberian link was severed very quickly. 

8 minutes ago, bluearmy said:

I posted the Luton Dp’s a while back - I think it’s around three days 

To all who are interested in the source of the air that is forecasted to be over our heads, following the isobars is one method, but that's very rough, since the directions change continually, and also the altitude of 'packets of air'.

A very useful tool is NOAA's HYSPLIT model. It computes the trajectories of air at different heights, so you can see where your local air will come from, based on the latest model runs. Only for the US models, like GFS and NAM though. Lots of variables to fiddle with.

https://www.ready.noaa.gov/HYSPLIT_traj.php

Select 'Compute forecast trajectories'.

See for example GFS 6Z for London on January 7th, where did the air at 10 meters and at 1500 m come from? And relative humidity along the way:

 

[Penrith Snow]

1 hour ago, Daniel* said:

Don’t you realise the air travels 1,200 miles? Theres plenty of distance for that air to cool It has no semblance to origins, and at present I think models aren’t capturing that. You’d think some people think it’s going to be a tropical easterly.

There was also evidently modification in early Feb 2009 very wintry for most of country the Siberian link was severed very quickly. 

I remember that well, i had 10cms of dry snow lying on the 2nd February 2009 but by the 3rd it had gone due to a quick rise in uppers and dew point, I was gutted.

I am not sure why everyone expects every easterly to be very cold, the easterly of early January 1963 became very modified in the New Year leading to a widespread thaw North of Manchester due to a rise in uppers. This lasted several days before Russia sourced Air returned.

Less cold easterlies are nothing new have seen many in the past and next week looks colder than some I have seen.

Anyway all this is just a build up to the post SSW freeze later in January.

Andy

[snowblind]

15 minutes ago, Scandinavian High. said:

Could it be case that we see overnight showers tuning more wintery next week and as day goes on turn more rain sleet.

Seems to be what the latest, slightly updated,met office outlook is suggesting. So could mean getting an overnight snowfall and probably melting a bit in the day, with temps still suppressed.  A few places might get lucky.

[AmatuerMet1963]

Thanks for all those kind words. i really thought i was going to be sidelined because science and math's are my worst subject where as. Biology, Ecology, ornithology and Oceanography is my forte.  I dont know where the BBC is going with this, but appears to be the wrong way to me!!! Northerly in January, especially with strong wind chill, cant be anything short of freezing can it? An earlier longer range possibility by  Mr Stanous of the BBC remarked that high pressure moving north and low pressure to south suggest a change in wind direction and although he said some east coastal showers may be rain , he didn't commit himself. But noted that wind speed would be stronger. That suggests to me the wind chill effect would actually make it colder.  

In any case my trusty Windy map comes in useful. I checked on its TOS a long time ago on posting, and very nice windy.com assistant said i was fine under their present licensing. You can see my premier member icon on right the little picture of Greta Thumberg.  

By the 8th January Im pretty interested by the huge swathes of Eastern Europe  all pointing their winds from the East. And notice how the , at Vilnius area of Russia pool  of frigid air is joining up near Gadansk, pushing into Europe.   chance of a Bear From East almost to 60% possibility. ECMWF used.  That's about my limit lol...

thanks again, for comments appreciate it

[Frosty.]

Ach, I admit I ‘‘twas a wee bit concerned when I saw the GEFS 6z mean turning somewhat milder towards mid Janvier!!!...but then I looked at the perturbations and discovered that many of them are cold / very cold longer term..and snaw too..turns out I had nae reason to worry!....happy new year again..well it already is..perhaps not happy but certainly the new year already in parts of the world, australasia at least! ...forgive my tone, I realise we are still in horrible COVID hell right now but I’m very positive about next year with all the vaccines etc!..peace gang..  

 

Edited December 31, 2020 by Jon Snow

[Methuselah]

1 hour ago, Daniel* said:

Don’t you realise the air travels 1,200 miles? Theres plenty of distance for that air to cool It has no semblance to origins, and at present I think models aren’t capturing that. You’d think some people think it’s going to be a tropical easterly.

There was also evidently modification in early Feb 2009 very wintry for most of country the Siberian link was severed very quickly. 

That's all true, Daniel... But as yet, this time, there's been no Siberian link to sever?

[sorepaw1]

7 minutes ago, AmatuerMet1963 said:

Thanks for all those kind words. i really thought i was going to be sidelined because science and math's are my worst subject where as. Biology, Ecology, ornithology and Oceanography is my forte.  I dont know where the BBC is going with this, but appears to be the wrong way to me!!! Northerly in January, especially with strong wind chill, cant be anything short of freezing can it? An earlier longer range possibility by  Mr Stanous of the BBC remarked that high pressure moving north and low pressure to south suggest a change in wind direction and although he said some east coastal showers may be rain , he didn't commit himself. But noted that wind speed would be stronger. That suggests to me the wind chill effect would actually make it colder.  

In any case my trusty Windy map comes in useful. I checked on its TOS a long time ago on posting, and very nice windy.com assistant said i was fine under their present licensing. You can see my premier member icon on right the little picture of Greta Thumberg.  

By the 8th January Im pretty interested by the huge swathes of Eastern Europe  all pointing their winds from the East. And notice how the , at Vilnius area of Russia pool  of frigid air is joining up near Gadansk, pushing into Europe.   chance of a Bear From East almost to 60% possibility. ECMWF used.  That's about my limit lol...

thanks again, for comments appreciate it

Fantastic post thanks for pointing this out.

I was thinking similar. 

Again great post 1st class