Model Output Discussion - Colder but how cold and for how long?

[Penguin16]

2 minutes ago, Ali1977 said:

The GEFS mean for Wednesday as mentioned earlier certainly brings the snow further north

The way things are going it’ll probably end up north of Orkney 

[Kasim Awan]

3 minutes ago, Ali1977 said:

The GEFS mean for Wednesday as mentioned earlier certainly brings the snow further north

10/15% chance imo.

[Jayfromcardiff]

3 minutes ago, Kasim Awan said:

10/15% chance imo.

I agree, very slim chance of this happening now especially with cross model agreement of it missing the UK to the South.

[Kasim Awan]

Atlantic very close at 144h the toppler next week looks quite temporary.

Ecm snow free for 90% of UK.

Edited January 13 by Kasim Awan

[booferking]

Ecm & Gfs very similar day 4.

[Cheshire Freeze]

1 hour ago, Kasim Awan said:

It never did - look to our South over the Azores and over the US. The reason this cold spell has gone wrong is evident right now. The Iberian high is far too strong which pulls the high away from trying to move into Greenland.

This limits the Greenland high resulting in the cold easterly being too far North. Then the Atlantic can quickly return.

This all likely to be a result of not enough SSW forcing in place as I discussed with @Cheshire Freeze. To conclude you can discuss the finer details of telleconnections but until the basics are in place such as strong SSW, low pressure into Iberia, optimal setup over the US, it's unlikely that a significant or sustained cold spell will materialise.

 

Yep called it ages ago via PM to you, as you know. As soon as that split SSW failed the writing was on the wall.

I’ve been fairly quiet in here because to be honest I didn’t want the backlash for being ‘negative’.

The trop teleconnections can take you so far but if the strat is against you (as it is since the displacement) then it’s sub optimal. It might be weaker than average but it’s spinning away where we don’t want it, rather than being split or displaced well away from our N or NW.

We can only hope that it’s not too wet going forward because I fear flooding will be the main news going forward if we go hyper zonal.

GFS is trending wetter and wetter, another 100mm of rain in some exposed western parts before month’s end.

Edited January 13 by Cheshire Freeze

[Weathizard]

You have to wonder given the background signals and such how in the name of all that’s holy we go from this astonishing chart to this in 4/5 days… staggering stuff, only the uk would manage not to get a sustained proper nationwide snowy cold spell out of that.

[mulzy]

When will the post-mortems begin?  Where did it all go wrong?  So this long chase will lead to 4/5 night-time frosts, 3-4C by day, and dry as a bone for London.  The dry bit I like after the deluge of December but we stayed up all night for this.  At least I got a snow flurry on Monday.  Roll on the next chase and guess what we'll do it again because we are truly nuts!

Edited January 13 by mulzy

[Continental Climate]

1 minute ago, Weathizard said:

You have to wonder given the background signals and such how in the name of all that’s holy we go from this astonishing chart to this in 4/5 days… staggering stuff, only the uk would manage not to get a sustained proper nationwide snowy cold spell out of that.

Those two charts you posted are quite staggering and sums up our luck sadly. 

[booferking]

12 hours ago, BLAST FROM THE PAST said:

t120

 

T144

 

sweeping what cold away?

 

BFTP

 

Atlantic brush in full flow this morning toppler at best.

[Kasim Awan]

2 minutes ago, Cheshire Freeze said:

Yep called it ages ago via PM to you, as you know. As soon as that split SSW failed the writing was on the wall.

I’ve been fairly quiet in here because to be honest I didn’t want the backlash for being ‘negative’.

The trop teleconnections can take you so far but if the strat is against you (as it is since the displacement) then it’s sub optimal.

We can only hope that it’s not too wet going forward because I fear flooding will be the main news going forward if we go hyper zonal.

I see things from a more statistical and synoptic perspective vs stratospheric or telleconnection such as yourself. This perspective has been significantly against anything substantial aswell. No amount of isolating specific telleconnection drivers can overcome the factors we have discussed. Yes flooding a significant concern now with the south westerlies forecast.

[feb1991blizzard]

7 minutes ago, Cheshire Freeze said:

. As soon as that split SSW failed the writing was on the wall.

 

The trop teleconnections can take you so far but if the strat is against you (as it is since the displacement) then it’s sub optimal.

Problem is now strat w2 and trop w2 look unerringly similar so how do we get out of it.

[That ECM]

The first chart T120 ecm. If ever there was one that shows why anything past T120 is JFF then this is it. Met did their piece on track of low and what was likely and then the two less likely. None of their deep dive had it tracking this far south.

second chart T48 ecm we’ve been watching this pattern come nearer for ages. Some said let’s get this in to the reliable and see what happens. Unfortunately for many it looks like snow will affect some but not as many as hoped.

final point. The skilled imo people who can look at background drivers and give an idea of a general pattern have been spot on. Do not judge on the basis that you haven’t got snow in your back yard.

Looking forward, it is suggested by the same people that a blocking set up may well be evident in the near future. Now I for one am pleased about this and will continue to look at the output to see. If blocking shows up in late gfs output and ecm then I will again only be looking at T120 plus JFF even if the met do another video.

Anyone who claims they knew the details of this week awhile go is talking rubbish. 

Edited January 13 by That ECM

[Weather-history]

The funny thing about GEM 0z run is that it actually extends the chilly spell for parts of England into the following week

Edited January 13 by Weather-history

[IDO]

The models bang home the collapse by Friday by doubling down, on the trend. The OPs, I would not care for means with the low from the Azores; it looks like it misses the south comfortably.

GFS: 

Snow for the next six days before the melt:

As expected, it is likely to be dry for many. The usual caveats.

Post D6-7, we see the pattern return before this cold spell—a barrage of wind and rain until the 29th (south faring better). There seems to be a lot of energy firing up, so some storms and a potent jet. That will likely burn out after a week, giving us maybe longer, drier spells between the systems.

Looking at the mean for GEM and GEFS at D16, there are nascent signs of maybe a Pacific ridge developing, but the impact on the UK would be days away from that:

Those means are consistent, as with the previous three-week wet spell. For those saying why I am seemingly confident of this spell, it is because the models are significantly better at modelling a westerly pattern like this compared to height rises, which are notoriously unreliable.

Some cold weather is incoming, but the UK, as always, has been mainly on the wrong side of this two-week colder interlude for snow for many, and for those hanging on an SSW, it is a poignant warning that even with the SSW (warming), we will need luck.

[Kasim Awan]

The setup coming up is not conducive for "troughs popping up everywhere". It's conducive for snow to northern hills, Cheshire gap snow showers, and snow into France.

[Harveyslugger]

1 minute ago, Kasim Awan said:

The setup coming up is not conducive for "troughs popping up everywhere". It's conducive for snow to northern hills, Cheshire gap snow showers, and snow into France.

And high ground West Wales.everyone keeps forgetting about that.most people don't know this but there are mountains in Pembrokeshire known as the preselis and they go up to similar height as Dartmoor and Exmoor but are never mentioned at all.

[feb1991blizzard]

Just now, Kasim Awan said:

The setup coming up is not conducive for "troughs popping up everywhere". It's conducive for snow to northern hills, Cheshire gap snow showers, and snow into France.

Yes i must admiti am certainly not in that camp now with a slack cold upper trough (not sure i ever was) after Early Dec 2022 and now, its ok with a slack surface low as well (evaporative cooling) but then you have mild sectors and they are usually marginal anyway.

[Kasim Awan]

7 minutes ago, Harveyslugger said:

And high ground West Wales.everyone keeps forgetting about that.most people don't know this but there are mountains in Pembrokeshire known as the preselis and they go up to similar height as Dartmoor and Exmoor but are never mentioned at all.

Yes on Monday potentially. The flow is now veering a little to North Westerly for good Pembrokshire activity looking more temporary.

5 minutes ago, feb1991blizzard said:

Yes i must admiti am certainly not in that camp now with a slack cold upper trough (not sure i ever was) after Early Dec 2022 and now, its ok with a slack surface low as well (evaporative cooling) but then you have mild sectors and they are usually marginal anyway.

We don't have a low stuck over the UK we have a progressive system with defined snow risk areas so less risk of troughs forming at short notice the vast majority will likely stay dry.

Edited January 13 by Kasim Awan

[Harveyslugger]

1 minute ago, Kasim Awan said:

The flow is now veering a little to North Westerly for good Pembrokshire activity looking more temporary.

Monday looks decent tho it's a straight north and in the past Pembrokeshire danglers are always underestimated by models.so hopefully I see some snow

[Taylorthesnowman]

Places will still see some snow during the week it seems.the northwest likely to get some flurries Thursday .very marginal by the looks of things.

[TillyS]

Oh dear 

 

All 3 models have the same Atlantic return with little variation in timescale: Friday/Saturday give or take a day.

In the shorter term, some cold days this coming week with the best chance of a bit of snow coming Wednesday from the occluded front across the north Midlands. A precariously marginal set up that one though from a westerly direction, so high ground in the north will be most favoured, especially the Pennines.

This is assuming that the models are now correct with the southern track of the Tuesday low. That could still change.

Otherwise, for southern Britain a colder number of days with little in the way of wintriness ahead of returning westerlies.

 

 

 

[TillyS]

24 minutes ago, Continental Climate said:

The vast majority of the country will see no snow by next thur/fi, which is a bitter blow considering the length of the chase. Things may look better by beginning of Feb however we all know how difficult it is to get out of zonality once it sets in. I'm not throwing the towel in for winter but jan I think is now finished. I just hope i see something on Tuesday for my location. 

Yep, back to a persistent problem this winter as mentioned by some on here:

1. No sustained northerly blocking

2. That bloody Iberian high … which is like a stone in the shoe, or whatever simile you care to choose (there are plenty of ruder options  )

[P-M]

I don't know what the issue is.  People declaring mild by the weekend. It's been forecast for days now plus the Meto allude to it. Besides that, they also mention a chance of colder conditions again after.

I think people forget these are computer models and don't make the weather it will do what it does. 

But the fact is we have a week of cold weather coming up and anything can happen as per previous cold spells. 

 

[Gowon]

The first time I've looked at the models since the 12z and I can't believe how quickly the cold has collapsed.

I'm hoping it's a data issue and they're all wrong