Model thread discussion - cold spell looming

[Ali1977]

Also to note is that this run keeps the lows coming in from the Atlantic on Tuesday  slightly further south , 850s staying lower in the SW and possibly a good start to prolonging the cold spell.

[Malarky]

Second low seems to be slightly further north and first low slightly further south. Could that indicate a different angle of attack? *Gets ruler out*

[Djdazzle]

3 minutes ago, Badgers01 said:

Except gfs precipitation model is not regarded at all ... 

Agreed. Likely to be underestimating the snow.

[Battleground Snow]

UKMO at 120. Not looking like the high will hold the low back here, but may get pleasantly surprised at 144

[Matt H]

A stronger surface ridge appearing over Scandinavia at t120 on the UKMO 12z. Very interesting!

[Paul_1978]

Unless there is a monumental shift in the models this afternoon, we will have to expect the cold spell is a Sunday to Friday event. It’s not a Feb 1991 repeat.

However, promising signs of the cold returning after a mild blip next weekend. 

Enjoy the week all - we spend half our lives chasing cold spells and we’re just about to get one, and the chase for the next one may just be around the corner!

[Notty]

UKMO and GFS Op at T+120

[Yarmy]

8 minutes ago, Djdazzle said:

Same stuff, different day. When are people going to actually realise that the precipitation charts are hopeless!

Of course, they all are, and they won't pick up any detail of the showers coming off the North sea. But it doesn't change the fact that by pulling the low southeastwards, the models are reducing the area of the UK over which the northern flank snow extends on Sunday.

Edited February 5, 2021 by Yarmy

[Buzz]

11 minutes ago, Cold Winter Night said:

Exactly this.

Milder T850 do not necessarily mean that the cold at the surface moves as easily.
Models are making more and more of those heights you circled and the Atlantic attack becomes less and less effective.

It's AAM, MJO, but also simply a cold, sinking air mass that will turn into a high.

ICON is another confirmation of a possibly lengthy cold spell.

 

Indeed. For example, would you believe that the following T850's would have produced a severe blizzard on 18th and 19th February 1978 ..... because many people in the south west had over a foot of snow and sub zero temperatures:

http://old.wetterzentrale.de/archive/ra/1978/Rrea00219780218.gif

http://old.wetterzentrale.de/archive/ra/1978/Rrea00219780219.gif

 

[Djdazzle]

1 minute ago, Yarmy said:

Of course, they all are, and they won't pick up any detail of the showers coming of the North sea. But it doesn't change the fact that by pulling the low southeastwards, the models are reducing the area of the UK over which the northern flank snow extends on Sunday.

Fair enough - but the slipping southwards was not really unexpected. I doubt that it will change much more now as we count down to T0.

[Runcible Spoon]

Many will have got carried away somewhat with the outrageous charts of a couple of days ago. Cold weather for a few days is nailed on for all. 12z's so far indicate the eastern side of the country will get snow for sure, though I'm sure some unlucky areas there may not.

Whilst the showers and convective streamers can and will pop up, the low res models wont get that right and even the hi res models will never be near 100% either.

Frontal snow with no 'gaps' in the precip line give much more comfort over surety, but the most recent model runs indicate more of a sleety or snow/rain event for the south and southwest middle of next week.

12z METO and ECM will hopefully show some improved decent frontal snow chances next week, but if gonna turn slushy or melt very soon after there, I'd rather it be 10 degrees, than 2! Slate grey skies and cold don't float my boat.

Still, I'll be pleased to see others fun in the regionals

[Notty]

UKMO -v- GFS Op at T+144

Better than 06z I think

[sheikhy]

Snowline further south and west again on 12z gfs at 144 hours!!!

[JamesL]

Latest 12z UKM shows the low at 120 further west and south in the Atlantic and the Scandinavian ridge further west and south than the 0z output 

 

There is a long way to run on this yet.
 

More forcing in coming runs could disrupt this low further 

[mountain shadow]

7 minutes ago, Paul_1978 said:

Unless there is a monumental shift in the models this afternoon, we will have to expect the cold spell is a Sunday to Friday event. It’s not a Feb 1991 repeat.

However, promising signs of the cold returning after a mild blip next weekend. 

Enjoy the week all - we spend half our lives chasing cold spells and we’re just about to get one, and the chase for the next one may just be around the corner!

It doesn't look like being anything noteworthy at all out West.

A few days of colder drier weather, a very brief spell of snow, then back to rain.

Still time for change I suppose.

[sheikhy]

Looks to me as though the cold is trying to fight back at 144 hours on both ukmo and gfs!!good start!!!

[Notty]

Stronger Scandi HP than 06z too

[PolarWarsaw]

The main focus of this evening's 12z are the angle at which a breakdown approaches - for those likely to miss out on the snow of any note (probably 70% of the nation) away from the far east and south, this is going to be the main aim of any snowfall hopes. We are unfortunately, going to need to annoy those in south by most likely turning their snow to rain so we can get in on the act.

Before then, as you were - showers in the east with decent accumulations. Manchester, Birmingham and right south to the Coast and all areas west likely to stay predominantly white with frost being what covers the paths. 

All a bit of a non-event away from Eastern coasts, Cold and dry is as much of a waste of winter as Mild and Bartlett. 

Meh. Vast upgrades needed for Central and Western areas for this to be any other than a standard winter event.

Edited February 5, 2021 by PolarWarsaw

[Djdazzle]

Anyone calling the cold spell over at the end of the week is being a bit premature. The block is putting up a bit more of a fight it seems.

[PolarWarsaw]

3 minutes ago, Djdazzle said:

Anyone calling the cold spell over at the end of the week is being a bit premature. The block is putting up a bit more of a fight it seems.

I don't think anyone has said that the cold spell won't last longer, it just doesn't look likely.

The key issue up for debate here, is whether we can upgrade any breakdown, or bring troughs into the spine of the country away from the East. 

For a larger majority of the country this is looking like a total non event and a 1-2CM snizzle covering, isn't notable either. 

That's the main focus of this evening. 

It would be a shame to go an entire winter without some sort of 'widespread' snowy spell. 

Edited February 5, 2021 by PolarWarsaw

[sheikhy]

And then i look at the ukmo between 72 and 120 hours and winds are south easterly which means maybe not as much shower activity with drier air of the continent!!

[Lukesluckybunch]

In watching that cold out east on the GFS at 174 could it be heading West towards us!

[Malarky]

Low spinning on itself now out in the Atlantic instead of going across us.

[Notty]

Just now, PolarWarsaw said:

I don't think anyone has said that the cold spell won't last longer, it just doesn't look likely.

The key issue up for debate here, is whether we can upgrade any breakdown, or bring troughs into the spine of the country away from the East. 

For a larger majority of the country this is looking like a total non event and a 1-2CM snizzle covering, isn't notable either. 

That's the main focus of this evening. 

I disagree. The main focus is model discussion. 

[Djdazzle]

1 minute ago, PolarWarsaw said:

I don't think anyone has said that the cold spell won't last longer, it just doesn't look likely.

The key issue up for debate here, is whether we can upgrade any breakdown, or bring troughs into the spine of the country away from the East. 

For a larger majority of the country this is looking like a total non event and a 1-2CM snizzle covering, isn't notable either. 

That's the main focus of this evening. 

Don't troughs tend to crop up at short notice though, and aren't usually well modelled?

I really think that many more people will get the snow that what the models are currently showing.