Model Output Discussion - Staying cold into the new year

[Mair Snaw]

So we go from a Greenland high to a Bartlett high in 4 days?? That cant be right can it?? Or is that some sort of SSW response?? Its definitely an odd one.

[Updated_Weather]

Thursday night fax chart,

Hopefully brings some excitement and hope for those currently snowless E/A

[Nick F]

Shame we can't take seriously anything past day 7 on the operationals. 18z GFS op is a corker of a run up to around day 12.

Easterly from Sunday cold enough (T850s of -7C eastern England) to generate snow showers off the North Sea inland that even may form  streamers. Then to top it off end of next week a bitterly cold Northerly develops.

Like the way it doesn't retrograde the Atlantic block so far NW like some previous runs, which led to the jet heading too far NE over western Europe, with the worst outcomes of a west-based -NAO.

Edited December 29, 2020 by Nick F

[Howie]

2 minutes ago, Mair Snaw said:

So we go from a Greenland high to a Bartlett high in 4 days?? That cant be right can it?? Or is that some sort of SSW response?? Its definitely an odd one.

I think it lost the plot and decided to revert to climatology 

[Mair Snaw]

Just now, Howie said:

I think it lost the plot and decided to revert to climatology 

Im hoping thats the case... i have for a few days been worrying that the upcoming ssw could kick us out of a favourable position into one thats not so favourable.. i hope im wrong.

[feb1991blizzard]

GEFS poor compared to 12z.

[damianslaw]

Outlook predominantly cold and possibly becoming very cold as we move through next week. When could we last say this going into a New Year, 2010. 11 years ago now, all periods since not one jot of cold on the horizon going into the New Year, though speculation for it was touted in 2013 thanks to SSW, but had to wait until 13 Jan for a change to cold.

In the shorter term more of the same, cold northerly influence, further wintry precipitation for some, frosts and low daytime maxima. More general snow expected in northern parts Thursday.

As we start 2021 the northerly becomes an easterly then heights set to retrogress to Greenland enabling possible trigger to some proper cold air from the north.

Locked in cold synoptics, the classic cold winters of yesteryear saw easterlies and northerlies relay each other..

2020 then ending in an unusual mode following the theme of the year as a whole, an oddity. In any other year I'd be thinking watch the cold be chased by the Atlantic , but just like the wonderful perpetual blue sky days of spring that went on and on..are we about to see weeks of perpetual cold during this strangest of winters.. I would not be at all surprised!

Edited December 29, 2020 by damianslaw

[kold weather]

10 minutes ago, Tim Bland said:

Looks a bit odd doesn’t it

Looks quite a complex pattern, though one I have seen various times before in both historical set-ups and hypothetical setups seen in ensembles.

There is a weak upper low feature that draws across Greenland around 240hrs which looks like it slams the door shut on the ridiging there and it all starts to sink southwards from that point in conjunction with that upper low that just sits and a general deepening of pressure in our section of the arctic.

Its got increased support from the models in the past 24hrs, so its realistic, though we have also seen these set-ups try to pop up in cold spells before only to kicked into touch once the time draws nearer.

[winterfreak]

5 minutes ago, Mair Snaw said:

Im hoping thats the case... i have for a few days been worrying that the upcoming ssw could kick us out of a favourable position into one thats not so favourable.. i hope im wrong.

The irony of it if it did

Edited December 29, 2020 by winterfreak
Typo

[Mike Poole]

Just before my iPad battery runs out I wanted to post this from the JMA T264:

[kold weather]

14 minutes ago, Mike Poole said:

I’ll leave you tonight with T312, GFS and GFS parallel:

Parallel is looking more likely to me, but either way there’s some cold coming....

I'm struggling with thay paralell.

Mainly because its actually strengthening a vortex lobe smack bang over the arctic between 192-240hrs.

At the same time nearly all other models are doing the opposite. Suggests to me the para is underdoing the northerly extent of any attempted ridging. Either that or it score a bit a coup!

Edited December 29, 2020 by kold weather

[Cheshire Freeze]

14 minutes ago, Tim Bland said:

Looks a bit odd doesn’t it

Looking to me like the strat displacement may shuffle the cards against us. A split would be preferable I think.

At this moment there are signals for such a warm up in mid Jan. Longer range extended EC and GEFS ensembles going for it. The question is a) will it happen and b) can we keep it temporary if it does.

[Allseasons-Si]

10 minutes ago, Updated_Weather said:

Thursday night fax chart,

Hopefully brings some excitement and hope for those currently snowless E/A

I am liking that triple point over northern England then it works it's way down down into the Midlands then SE.

[Allseasons-Si]

4 minutes ago, Mike Poole said:

Just before my iPad battery runs out I wanted to post this from the JMA T264:

Then some,...the pv is all but disappeared.

 

[Djdazzle]

The end of the GFS run may have no connection to the SSW - we’ve seen this kind of thing quite often in FI.

[Don]

3 hours ago, chionomaniac said:

Most times that we are praying for an SSW we don’t see 100hPa u winds heading towards record low levels. Especially with the disruption Atlantic based. Most of the time we are trying to knock the strat vortex off it’s perch. This is very different this time, so this is why I am a little bit sceptical of papers which have showed the SSW trop response when the strat PV is at a max

Ref to a SSW ruining things, didn't this happen in winter 2008/09?  We had a SSW at the end of January 2009, which led to a very cold and snowy start to  February, only for it to turn very mild during the second half?  Winter up to that point had been rather cold without a SSW?  Gavin Partridge also mentioned something similar in his video today about this upcoming SSW potentially being a foe rather than a friend.

Edited December 29, 2020 by Don

[SMU]

11 minutes ago, feb1991blizzard said:

GEFS poor compared to 12z.

18z always a shambles.

[Djdazzle]

1 minute ago, Steve Murr said:

18z always a shambles.

Do you include the op in that assessment too?

[More Runs Needed]

Wouldn't the effects of the SSW be too soon to be the reason for the poor extreme FI in tonight's run? 

[SMU]

1 minute ago, Djdazzle said:

Do you include the op in that assessment too?

Not really but as per continued assessment > if its a volatile unexpected operational with features that just wont happen then its a scrapper

If it fits in generally with UKMO then its worth a look---

[sheikhy]

17 minutes ago, feb1991blizzard said:

GEFS poor compared to 12z.

The 850s out to day 10 look really good!!so you mean in fi?

[Don]

15 minutes ago, CreweCold said:

Looking to me like the strat displacement may shuffle the cards against us. A split would be preferable I think.

At this moment there are signals for such a warm up in mid Jan. Longer range extended EC and GEFS ensembles going for it. The question is a) will it happen and b) can we keep it temporary if it does.

That's the point.  I think the upcoming SSW will be the key to how winter 2020/21 pans out overall.  A split is the preferred choice over a displacement.  However, the fact we are talking about a potential 'warm up' in mid January when we are still in December surely means we are not in a bad place ATM?!

Edited December 29, 2020 by Don

[feb1991blizzard]

4 minutes ago, sheikhy said:

The 850s out to day 10 look really good!!so you mean in fi?

Not quite as good at D10 and H500 pattern much poorer with a lot of collapsed ridge runs in there.

[chionomaniac]

So, hence my keenness not to rush through the SSW. It’s a bit like looking on your computer searching for snow, whilst it’s snowing outside. Open the curtains and move away from the computer!

[chionomaniac]

17 minutes ago, Don said:

Ref to a SSW ruining things, didn't this happen in winter 2008/09?  We had a SSW at the end of January 2009, which led to a very cold and snowy start to  February, only for it to turn very mild during the second half?  Winter up to that point had been rather cold without a SSW?  Gavin Partridge also mentioned something similar in his video today about this upcoming SSW potentially being a foe rather than a friend.

Nope. That is wrong. The strong split in 2009 was responsible for the easterly in early feb. It was the lack of subsequent blocking in the right place that hindered any further cold opportunities. But that split delivered and led to one of the first met office red warnings.