Model output discussion - proper cold spell inbound?

[Paul]

Please only post about the model output in this thread - if you're unsure what this entails, and what thread you should be using, please see our posting guide:
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We don't want to do it, but we have and will either block from posting, or pre-moderate the posts of those who continually post off topic posts in here. So please don't let that be you, with what may be a very interesting/exciting spell of weather on the way.  

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[jvenge]

GEFS 06z mean anomaly for the next 16 days. 

[karlos1983]

7 minutes ago, jvenge said:

GEFS 06z mean anomaly for the next 16 days. 

Impressive, 5-7C below average at the surface  This could be the most noteworthy cold spell for some time in the UK, especially more southern areas which have struggled to register a frost for all of January. 

[tight isobar]

500 geo-pot-stamps 

Some overwelming support for a notable spell...

Some real corkers in there..

Ramdom days...next tuesday...nxt thursday.

Potential is massive now!!!

Edited February 1, 2018 by tight isobar

[london-snow]

Just now, karlos1983 said:

Impressive, 5-7C below average at the surface  This could be the most noteworthy cold spell for some time in the UK, especially more southern areas which have struggled to register a frost for all of January. 

We have had some quite clear and frosty days over the course of winter even a few slushy deposits of wet snow but nothing out of the ordinary and certainly nothing compared to other parts of the uk.

This possible sustained cold spell could make up for the past letdowns and garden paths it sure is fascinating viewing at the moment. Wouldn’t worry too much about snow possibilities atm imo.

[karlos1983]

Thought I’d go back to 00z from the 29th Jan, to see what the “big 3” were showing for this coming Sunday at 01:00hrs, really just to see which had a good grip of what might be occurring at the +144 (D6) timeframe. UKMO, ECM, GFS in that order it looks to me. Although both GFS and ECM were miles away from the UKMO truth be told.

UKMO

GFS   

ECM  

 

UKMO has bossed this upcoming cold spell so far! 

Edited February 1, 2018 by karlos1983

[Man With Beard]

25 minutes ago, jvenge said:

GEFS 06z mean anomaly for the next 16 days. 

What really strikes me is the anomaly of cold to the NW at day 5 and day 8.

The hype over this cold spell has been the Scandi High cold but really it should be the cold coming off the Atlantic. The -10C 850hpa line coming off a WNWly? This has NEVER happened before!

And again!

And here's why: minus 40C 850s over Canada and a very wide area under minus 32C. Again, I have not seen this?

If we can just get some darn precipitation to fall, the entire country will go white this week. And it's not as if we're sat under a massive high pressure - it's Atlantic low + Euro low + another Atlantic low - Come on, surely it's gotta happen!

[Guest]

I have just produced one of my long posts on the teleconnections thread. This is partly model related and some of my regular readers will probably like to take a look. I explain why I'm focusing my posts on the specialist thread and not on the winter model thread. Here's the link:

https://www.netweather.tv/forum/topic/89161-learning-about-teleconnection-science-and-background-signals/?page=5

or just click on the chart below:

 

[karlos1983]

13 minutes ago, Man With Beard said:

What really strikes me is the anomaly of cold to the NW at day 5 and day 8.

The hype over this cold spell has been the Scandi High cold but really it should be the cold coming off the Atlantic. The -10C 850hpa line coming off a WNWly? This has NEVER happened before!

 

If we can just get some darn precipitation to fall, the entire country will go white this week. And it's not as if we're sat under a massive high pressure - it's Atlantic low + Euro low + another Atlantic low - Come on, surely it's gotta happen!

maybe a great illustration of why we so often struggle when the PV is placed more towards Greenland? if that were the case now, we would likely be in the warm sector in the Atlantic and the cold would be much further East. The PV being further west is kind of a big deal. US cold and UK cold is not common, but as we are surely about to find out, not impossible! 

Azores high definitely been a help rather than a hindrance for a change 

Edited February 1, 2018 by karlos1983

[Jimmyh]

look at this the southeastern corner buried and its only 4 days away t 96 ish exciting model watching

[Frosty.]

Just had a look through the GEFS 6z mean and next week in particular looks very cold nationwide with maxima close to or around freezing point so some ice days with severe overnight frosts and icy patches with snow at times..potentially the most wintry spell of the season so far across most or all of the uk looks to be on the way..

Edited February 1, 2018 by Frosty.

[craigore]

10 minutes ago, Jimmyh said:

look at this the southeastern corner buried and its only 4 days away t 96 ish exciting model watching

Assuming this is frontel snow band , will it continie right across the S.E or are we looking at it getting pushed bck west by pressure rise from East. (So some places would get a double wammy..)

[Paul]

Almost, but not quite a record - 4 off topic posts in the first 10. For metoffice forecasts, please head to the met office forecast thread (who'd a thunk it!), or at the very least the banter thread.

And don't forget - if you start your post with 'I think this is off topic, but' or similar, then not only will your post very likely be removed, but you may also be responsible for a member of the team spontaneously combusting, so please don't hit submit if you feel the need to use those words.  

Thanks!

[Jimmyh]

1 minute ago, craigore said:

Assuming this is frontel snow band , will it continie right across the S.E or are we looking at it getting pushed bck west by pressure rise from East. (So some places would get a double wammy..)

I am starting with frontel finishing with it biting back from the east.

Think we want to get it to t48 then we can get really excited.

Can I ask the same question as MWB, when was last time we got such cold in off atlantic?

 

[captaincroc]

Genuine question to the more experienced posters...but, playing devils advocate, what could technically go wrong within the 96hr time frame? Is there anything that could stop this?

[Snowman.]

2 minutes ago, captaincroc said:

Genuine question to the more experienced posters...but, playing devils advocate, what could technically go wrong within the 96hr time frame? Is there anything that could stop this?

Trigger shortwave not heading SE. Another shortwave spawns that stops cold air heading west/retrogression of heights. 

You'd be surprised those who was here for December 2012 will remember the pain of going to be with an easterly and 96 then waking up to a horror show.

[Coopsy]

Just now, SN0WM4N said:

Trigger shortwave not heading SE. Another shortwave spawns that stops cold air heading west/retrogression of heights. 

You'd be surprised those who was here for December 2012 will remember the pain of going to be with an easterly and 96 then waking up to a horror show.

Are there any real differences between now and then that make the probability of this happening higher or lower?

[swebby]

7 minutes ago, captaincroc said:

Genuine question to the more experienced posters...but, playing devils advocate, what could technically go wrong within the 96hr time frame? Is there anything that could stop this?

As snowm4n says - Dec 2012 - if i recall correctly all but one member of the ECM ensembles (51 out of 52?) forecasting an easterly and the stand alone member was the one that was correct.

[karlos1983]

Just now, c00ps said:

Are there any real differences between now and then that make the probability of this happening higher or lower?

Once we get to this point below (+72), it is hard to imagine a Shortwave penetrating the high pressure. PV far enough away from us to hopefully not throw a shortwave into the mix, but @nick sussex is the Shortwave king, so maybe he can elaborate or correct me if I'm wrong

[Rocheydub]

On Dec 2012, didn’t UKMO spot it was a failure first? Also seem to recall Fergie saying Mogreps didn’t back it fully either. Cross model agreement is the only decider for me and within 72 hours. I’d be 85% confident this time around!

[Frosty.]

As I mentioned further up the page, the GEFS 6z mean shows a very cold spell next week with ice days, severe frosts and snow in the pipeline, indeed, there is potential for significant snow early next week and at times further ahead too..winter set to return with a vengeance it seems and I can't wait!!❄❄❄❄❄❄❄❄❄

[winterof79]

1 hour ago, Jimmyh said:

look at this the southeastern corner buried and its only 4 days away t 96 ish exciting model watching

Just for balance

[Snowman.]

6 minutes ago, c00ps said:

Are there any real differences between now and then that make the probability of this happening higher or lower?

UKMO doesn't show anything of the sort so we're 95% fine. Dec 2012 UKMO was having none of it and it proved correct.

General rule of thumb is if the UKMO isn't on board then don't get your hopes up but in this situation it is.

[karlos1983]

Talking of +72 and cross model agreement, here are the ECM/UKMO/GFS for said timeframe

Looking good to me for the overall theme! details have slight differences! 

If things were to go the way of the Pear now, it would be some turnaround! Would go down in Netweather folk-law history no doubt! Let’s not even consider that. 

Edited February 1, 2018 by karlos1983

[Optimus Prime]

A brief easterly flow into a North Westerly looks most likely by the looks of it then.

Some fairly appreciable cold, coming out from NW Europe and more particularly out of Canada/Greenland as the low pressure systems move over the UK, toppling over the Azores high pressure with is displaced further north than normal. Normally this would bring transient snow to northern areas but this time, with some exceptionally cold air moving out from Canada (currently 15-20°c below normal!) it will predominantly be snow next week.

A potential for some memorable winter weather over the coming week.

Edited February 1, 2018 by Optimus Prime