Matt Taylor rightly cautious and non-committal when questioned about the prospects of cold and snow on BBC Breakfast this morning.
As strong as the signals are, we are still several days of model iterations away from calling any scenario that might deliver snowfall. Having said that I personally think Feb 2019 might be one that’s mentioned in years to come.

Yep agree with all that. I am still of the optimistic that we will be in a very cold east/north easterly airflow by the 25th but looking at the variability from the models this morning its like pinning the tail on a donkey time.

The only thing the models agree on is that it is going to get colder. I suppose though when a lot of the attention is post t192 then it is hardly surprising. Also the 22nd is roughly the date of the downwelling to the trop which the models are struggling to come to grips with.

 

No doubt you are correct doctormog - I have not been following the charts for a few days. I was hoping for something better than the models are showing today on resuming attention and hence I am disappointed to say the least. We are not seeing a quick trop response to the SSW which favours the UK and I think the problem is the lump of PV which is still present on the Canadian side of the Pond. What is missing, is HLB which could open the door to sustained UK cold and snow, even though we should anticipate it given the SSW. It appears the AO is trending heavily negative, but that does not help us if the NAO does not go negative too, in a position which stops mild sectors from being thrown across the UK. Getting brief cold incursions and transient rain to snow to rain events, does not float my boat - I would rather have mild and dry than cold rain.

The output is messy and mehy (if I can say that) for the southern half of the UK but I wouldn't discount the possibility of a significant snow event. Also there is a greater than average chance of the cold period lasting into February. 

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The pattern is interesting and patience is required. Its been a long wait but we shall find out very soon (next 2-5 days IMO)  

With model watching observing what is happening previously is as important as observing what may happen in the future.

 Cold shots have repeatedly surged SE'wards over eastern and then central europe at weekly intervals since Christmas as our high pressure sticks close by. Each PM cold shot is getting closer.

The next cold shot planned on Thursday is the first one that brings the risk of some wintry precipitation. The fact that most models show some appreciable precipitation with this shows that our HP has finally been eroded sufficiently by this next shot.

I don't believe this westward retrogressing pattern is tied in with the SSW though (this pattern started around 23rd December before the SSW had even occurred) !

The long term signals from the JMA, CFS and ECM scream something significant and cannot be ignored. These have picked up the troposphere response following the reversal of zonal winds in early January.

23-26th of the January should be the period that we should start to see high pressure inflate over Iceland after the next cold shot around 23rd January if this is all going to happen. A few minority ECM members are starting to show this. 

Its not a done deal though as the atmosphere is fighting against a newly established westerly QBO and SST profiles that promote a positive NAO pattern.

Whatever happens it isn't likely to be too mild. The NW/SE jet alignment will ensure some cold zonality meaning that many northern areas could do quite well at times. For the north its a win win. For the south we are relying on that tropospheric response.

Key is that height rise over Iceland circa 24th January ish.

We will find out very soon. In model land that's around 300 hours at the moment  

 

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I think that is a good analysis Steve. Scotland will probably do well whatever happens and the northern Pennines might get in on the fun, but for lowland Britain in the south, we need HLB to become established - fingers crossed.

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This really is totally just for fun but it’s not often you see snow cover that widespread (even in the fantasy island virtual world of the models. 

Please do not read into this post that this is what I expect to happen!

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Not wanting to muddy the waters but there has been quite significant change to the strat profile from the 18z yesterday. The low gph heights over Canada are forecast to spread eastward across Greenland and Iceland.
This is forecast at all levels.
Up to and including yesterdays 12z the profile looked great. I can understand the lowest levels being influenced by the trop pattern but to see such changes at the 30mb level as early as t200 onwards does not look good.The down welling and split vortices should be looking stronger with time not the other way around.
Some to definitely keep an eye on.

This really is totally just for fun but it’s not often you see snow cover that widespread (even in the fantasy island virtual world of the models. 

Please do not read into this post that this is what I expect to happen!

Its a banker IMBY doc. Shades of Feb 96 for snow totals there. ❤️

Signs from the GEFS06z that the cold period is shaping out towards the end of the month. That goes against some recent updates and the ECM46 10/01.

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The blanket "Scotland will do well out of this" comments are not wholly correct.  Parts of Scotland will, the same as parts of the rest of UK.  Edinburgh and the  parts of the East coast does not usually get snow out of Northerly events and even NWly can lead to showers but often little appreciable precipitation. 

That said, I'n not complaining about the outlook at all and I can't recall seeing a set up like this in recent memory, with lows diving SE across the country.

Signs from the GEFS06z that the cold period is shaping out towards the end of the month. That goes against some recent updates and the ECM46 10/01.

The T850 mean has certainly shifted up significantly since the 0z after being consistently flat around -5 for a few runs. Quite a few milder members in there.

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This really is totally just for fun but it’s not often you see snow cover that widespread (even in the fantasy island virtual world of the models. 

Please do not read into this post that this is what I expect to happen!

Is this what they call a 'snow bomb'? (the latest idiotic, reductive media soundbite) 

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The T850 mean has certainly shifted up significantly since the 0z after being consistently flat around -5 for a few runs. Quite a few milder members in there.

Indeed. I would want to see it repeated several times before being confident that a shift to a less cold position is starting to emerge. The next ECM46 will be interesting too. 

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Indeed. I would want to see it repeated several times before being confident that a shift to a less cold position is starting to emerge. The next ECM46 will be interesting too. 

To be fair the forecasts are more confident about the snow potential for parts of the north and that is reflected in the ensembles

 

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Signs from the GEFS06z that the cold period is shaping out towards the end of the month. That goes against some recent updates and the ECM46 10/01.

Yes I've noticed since yesterday that the ensemble mean has been consistently ticking up right at the end. I suppose that is just reversion to the mean due to scatter though.

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Just catching up with the GFS Para 6z its easily the coldest run of the winter brutal cold in the day 10 to 16 region . Goes cold as early as day 5 as well. Loads of snow which causes the low temps later on.

 

 

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We need to keep a check on these T2m temps. There appears to be a slight uptick at the end.

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Just catching up with the GFS Para 6z its easily the coldest run of the winter brutal cold in the day 10 to 16 region . Goes cold as early as day 5 as well. Loads of snow which causes the low temps later on.

 

Really ?

 

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Really ?

 

 

Have a look at the 2m temps day 10 onwards 

 

http://www.wetterzentrale.de/de/topkarten.php?map=20&model=gfs&var=5&run=6&time=312&lid=PARA&h=0&mv=0&tr=3#mapref

 

 

 

 

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 Have a look at the 2m temps day 10 onwards 

 http://www.wetterzentrale.de/de/topkarten.php?map=20&model=gfs&var=5&run=6&time=312&lid=PARA&h=0&mv=0&tr=3#mapref

Gosh ! 

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It’s amazing what a bit of deep cold and snow cover can do. t850s are useful but rarely in isolation, the 500hPa/SLP charts are a bit more useful but do sometimes not provide the full picture. The 06z GFSP was probably a “snowy anomaly” but it is not entirely out of the question.

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