The hunt for cold - Model discussion (late November)

[ArHu3]

5 minutes ago, Paul said:

Can we drop the petty, mostly pointless argument over the flow on a chart which will be different in 3 hours anyway please.

 

A little tip for people like me that get confused when the isobars get complicated you can see winds (vent 10m) in some models or see the 850hPa temperature to watch flow

Edited November 27, 2018 by ArHu3

[BlueHedgehog074]

Personally, I probably would have left the posts unhidden as I didn’t feel there was anything too wrong with them really. (I guess us admins/mods/hosts all see things a bit differently at times and doing what they feel is appropriate). But maybe it might just be best to drop the Easterly debate. Thanks guys!  

Edited November 27, 2018 by DiagonalRedLine

[Mike Poole]

So, before the 18z(s) roll, what has today told us?  Yesterday's 12z suite offered a smorgasbord of possibilities mostly with a strong element of high latitude blocking, although not all beneficial as far as UK cold is concerned.  

0z were a letdown (as usual - I'm sure there must be a scientific reason for this due to when the data is collected, I'm not imagining it...). 

Moving on.  Some sort of Arctic high looks highly probable.  Which means there is no coherent trop vortex, phew!  But a lot of runs seem to invigorate the jet across the Atlantic, without an obvious zonal pattern, these look (slightly) suspect to me.  A few runs, more so on the ens, push Atlantic heights north towards Greenland, the earlier evolution of a Scandi high looks more probable maybe?  

And then there's the strat, FV3 has the best chart for that T336:

But no obvious SSW yet, weakens vortex a bit.  In my view the days ahead hold very interesting model viewing indeed.

Edited November 27, 2018 by Mike Poole

[bluearmy]

Encouraging to see ec mean taking the mean ridge west out of Europe by day 10 ...... that allows for it to ridge a little to our west and for the sceuro trough to back further west 

 

[frosty ground]

Small direction change of the flow more northerly at 132 hours on the 18z 

[Mike Poole]

So has this one got the oomph to drive heights north toward Greenland?  I think it might...GFS T180:

[frosty ground]

8 minutes ago, Mike Poole said:

So has this one got the oomph to drive heights north toward Greenland?  I think it might...GFS T180:

Might not make it to Greenland but it’s causing a disruption 

[Mike Poole]

If this run goes like I think it might it's going to be making a complete dog's breakfast of the whole NH, pub run at T216:

What's not to like?

Edited November 27, 2018 by Mike Poole

[Cheshire Freeze]

There's that big Russian ridge as advertised on the EC mean

[frosty ground]

5 minutes ago, Mike Poole said:

If this run goes like I think it might it's going to be making a complete dog's breakfast of the whole NH, pub run at T216:

What's not to like?

By day 10 interest is peaking Siberian high pushing west N Atlantic stopped in its track

[Cheshire Freeze]

And here's why I didn't see the despondency in that EC mean...

When you got a big Siberian ridge like that to play with, things like this can pop up 

[ICE COLD]

Gfs 18z T264 . 

[ICE COLD]

Yep this is turning into a nice run ( blocking galore ) . 

[feb1991blizzard]

3 minutes ago, CreweCold said:

And here's why I didn't see the despondency in that EC mean...

When you got a big Siberian ridge like that to play with, things like this can pop up 

Yes - hemispherically - this is going to be a snorter.

[Mike Poole]

One word for the pub run T336 - retrogression:

[Cheshire Freeze]

1 minute ago, Mike Poole said:

One word for the pub run T336 - retrogression:

Run the progression from 240 hrs on and see how the Canadian vortex gets ripped to bits

[booferking]

Gfs looking much better the candian vortex is spilling across the Atlantic..

[ICE COLD]

Jet way south into Europe. That’s what we want . 

[Mike Poole]

11 minutes ago, CreweCold said:

Run the progression from 240 hrs on and see how the Canadian vortex gets ripped to bits

Ooh, yes, impressive that CC, we need to see more runs like this!

Done an animation so people can see what we're talking about, ignore the UK, watch the purples to our NW!

Edited November 27, 2018 by Mike Poole

[bluearmy]

6 eps clusters right out to day 15 .......maybe the mean is more useful than some might think .........

[Cheshire Freeze]

5 minutes ago, Mike Poole said:

Ooh, yes, impressive that CC, we need to see more runs like this!

It is likely to be the repeating pattern of the winter...Scandi heights transferring across to Greenland. Especially confident of this later December and January given available seasonal model guidance and from reading between the lines of what GP has had to say.

Some of the most memorable winters are characterised by this sort of blocking signal as it can maintain itself for a prolonged amount of time once it sets in.

This isn't your tin pot, ten a penny N Atlantic ridge scenario that's expected... 

Edited November 27, 2018 by CreweCold

[ArHu3]

On 26/11/2018 at 16:20, Mucka said:

I'm genuinely surprised by how flat GFS was in the Scandi region day 7+ today, not sure why it wants to put the Atlantic into overdrive and force the jet over the top but even the parallel is much the same.

 

 

Its mjo forecast went into the cod earlier today, so the flatness is expected 

[Cheshire Freeze]

Next is to check the GEFS mean in FI to see whether the Svalbard HP anomaly is maintained/intensified

You can see it here on the 12z suite

It's a big indicator of the AO going negative

Edited November 27, 2018 by CreweCold

[BlueHedgehog074]

The drunken GFS (18Z) certainly brings the battle back between the Atlantic and the block! 

Albeit the Atlantic loses right at the end.

Lows being squashed and disrupting over Southern UK with an Easterly feed. 

All change I imagine on the next run. However, if support for this suddenly gathers pace, it could be worth paying more attention too. Particularly as their may indeed be possibilities for blocking (whether favourable for snow or not is indefinite) to re-establish sometime next month. 

[Cheshire Freeze]

I'm getting the impression that this year we may get a spell of winter weather that will coincide with the coldest part of the year...and that will be utterly amazing if it were to happen, given the crud we've had over the past few years.