Model output discussion - cold spell approaching?

[snowking]

4 minutes ago, Notty said:

HP trying to build from the Pacific to Scandi. Arctic High has effectively gone. Would that encourage HP over Scandi?

It's an interesting point and some recent GFS suites have hinted at the possibility of a surface high developing in Scandinavia in the last few days, though nothing concrete has yet developed along these lines.

The big Pacific ridge is really shaking things up into the medium term, and with heights transferring ~ Pacific - Atlantic/Eurasia, nothing is off the table in terms of possibilities in the next 10-15 days. Models hate handling these sorts of scenarios.

For what it's worth on the longwave scale, I think the 0z suites were far too keen to remove heights from the Arctic region (apart from the ECMWF) and so was probably just an overreaction to something. That doesn't change the trials and tribulations in the shorter term for our tiny island, but given current model volatility, as @Nick F suggested earlier, probably best not to concern yourself with too much more than +144 for now.

[Battleground Snow]

Arome and arpege really going for it with Thursdays snow, some areas may get an orange warning for this, Harmonie not as enthusiastic however.

 

[Drifter]

This is where GFS drives me mad. 
I think in reality the trough would disrupt but GFS instead steers it northwards, ruining the whole pattern     

[Singularity]

 

Well, the GFS(P) offers something colder for days 8-10. Possible if the low south of Greenland is held back more. Akin to the ECM 00z in that respect but with the low taking longer to deepen. Funnily enough that ECM run was the best for keeping the Iberian heights down - might have looked pretty good had the low not bombed out.

[Tim Bland]

7 minutes ago, IDO said:

That is the gfsP and low-res so good luck with that landing? 

Here’s the Aperge and Euro4 .

UKV also showing widespread snow on sat even for some southern parts..scroll back a few goes 

[Battleground Snow]

Longer term this is what I think our best hope is : the Pacific / Arctic high squeezing the Asian vortex south.

 

[Tim Bland]

GFSp 00z Vs 06z showing colored uppers. Just need jet to go a bit further south and it’s bingo for most. 

[Methuselah]

Here's something we ain't seen for a while -- and hopefully won't be seeing for a good while longer:

    

[Frosty.]

Tomorrow could be wintry for some according too the Gfs 6z operational?...never mind looking for snow next week and beyond..there’s some right under our noses !

[chris55]

P19 keeps the milder air at bay on Saturday, a few colder runs early on.

 

[Tim Bland]

Rain turning to snow as it just the cold air ..

[IDO]

5 minutes ago, Gustywind said:

Think it’s perfectly feasible though that as we get closer we see the pattern edge further south, and systems slightly weaker. This then brings snow more into play for parts of the U.K. next week (North always favoured). The models may have overreacted to the new signal they’ve picked up on.

Yes, I agree, with snow, sometimes it is nowcasting, so do not rule it out, but these charts can be misleading if taken literally.

1 minute ago, Tim Bland said:

Here’s the Aperge and Euro4 .

UKV also showing widespread snow on sat even for some southern parts..scroll back a few goes 

I will believe it when I see it. The hi-res GFS snow depth does not really activate in the south until d10 and that will not last long on the 06z:

[Chesil View]

4 minutes ago, General Cluster said:

Here's something we ain't seen for a while -- and hopefully won't be seeing for a good while longer:

    

When the GFS loses the plot it really loses the plot.

[alexisj9]

1 hour ago, That ECM said:

 

It's lost, very unsure of more or less everywhere.  I wouldn't be surprised if all models where so unsure at the moment.

[snowangel32]

16 minutes ago, I remember Atlantic 252 said:

better than the 00, but safe to say trends are to push the cold air back, now looks like late next week, rather than Tue/Wed

From an imby perspective I am banking that and running lol. Midlands hit real bad there. But the models can't even agree on the Snow risk for tomorrow let alone over a week away. Chocolate fireguard comes to mind but still nice to see after the dagger to the heart for coldies this morning.

[Mucka]

I think with GFSp we can ignore anything past around this point (We can ignore anything past 72h in reality but you get my drift)

If the low must phase then GFSp shows the way we can salvage some cold by not having the low blow up and just phase with the base of the trough.

If we can get somewhere around here we could still get some sustained deep cold and low disrupting to the S bringing plenty of snow where the airmasses meet - hopefully keeping us on the cold side.

[Notty]

1 minute ago, alexisj9 said:

It's lost, very unsure of more or less everywhere.  I wouldn't be surprised if all models where so unsure at the moment.

Even the GFS and GFS(P) are completely different.

I just wish I could stop looking at the longer range. Can I get help on the NHS for this addiction?

[Jason M]

1 minute ago, Broadmayne blizzard said:

When the GFS loses the plot it really loses the plot.

Has it though? The evolution of a push of strong heights to our south is fairly typical of a west based -NAO. Its the classic of a warm push from the south to end a cold spell except this time we don't even get the cold spell.

I suspect what we saw last night was the extreme cold end of the range of possibilities, this morning we are seeing the extreme mild end (maybe?). 

Its not a done deal yet though as we are still talking about 8/9/10 days away as always. The trend is not our friend this morning though.

[Battleground Snow]

Very slight improvement on the mean.. 

I'm still optimistic for the end of January, especially once we get that pesky MJO to behave.

 

[That ECM]

5 minutes ago, alexisj9 said:

It's lost, very unsure of more or less everywhere.  I wouldn't be surprised if all models where so unsure at the moment.

Apologies to Paul and others for posting a chart with no words and just emoji and thanks to mountain for clarifying.

I agree, look at this lot at T192. Although the mean is better than previous run. Just going to have to watch it unfold.

[IDO]

Looking at the gefs and at d8 the op looks one of the worst case scenarios:

 

Though I am not going to spin it, the members show little inclination for snow in the south up to d8^^^

[Tim Bland]

We have gone from a Greenland high to a 945 low

[Tim Bland]

13 minutes ago, IDO said:

Yes, I agree, with snow, sometimes it is nowcasting, so do not rule it out, but these charts can be misleading if taken literally.

I will believe it when I see it. The hi-res GFS snow depth does not really activate in the south until d10 and that will not last long on the 06z:

Hmm. I’m not sure the GFS ‘high res’ will trump the Aperge, Euro4 and UKV etc. Time will tell...

[Methuselah]

I look at these T384 charts and (once I've stopped ROFLing) wonder what sort of weather would we might now be having, were it not for the SSW -- if the tPV was between Greenland and Alaska-Canada:

    

 

Edited January 13, 2021 by General Cluster

[Battleground Snow]

32 minutes ago, Battleground Snow said:

Arome and arpege really going for it with Thursdays snow, some areas may get an orange warning for this, Harmonie not as enthusiastic however.

 

Hmmm there is an amber warning out now for the north, but no adjustments further south of the yellow warning