Model output discussion - Post SSW - Will it turn cold?

[bluearmy]

And another thing ........ someone asked before about these desperately low uppers approaching the north sea and how they are likely to be moderated on their crossing. I have a larger concern and that is related to the lowest part of the cold pool being on a track across the Baltic or the North Sea.  I would just about think that the Baltic would allow a crossing without a shortwave appearing but the idea that we could have sub -18/20c uppers reaching the Norwegian coastline and continuing merrily wsw  is one which presents a huge risk of a shortwave deflection northwest. For this reason the far n of scandi ridge is a riskier solution. Whilst we want to see the ridge gain enough latitude to ensure the cold pool doesn’t end up too far south, we also need to be careful it isn’t too far north.  

Edited February 17, 2018 by bluearmy

[frosty ground]

2 minutes ago, bluearmy said:

And another thing ........ someone asked before about these desperately low uppers approaching the north sea and how they are likely to be moderated on their crossing. I have a larger concern and that is related to the lowest part of the cold pool being on a track across the Baltic or the North Sea.  I would just about think that the Baltic would allow a crossing without a shortwave appearing but the idea that we could have sub -18/20c uppers reaching the Norwegian coastline and continuing merrily wsw  is one which presents a huge risk of a shortwave deflection northwest. For this reason the far n of scandi ridge is a riskier solution. Whilst we want to see the ridge gain enough latitude to ensure the cold pool doesn’t end up too far south, we also need to be careful it isn’t too far north.  

No issue if you have the jet swinging round the high driving them west thou surely. 

[Deep Snow please]

Ignore wrong thread.

Edited February 17, 2018 by Deep Snow please

[ALL ABOARD]

Icon poor compared to earlier run. 

To much forcing from the PV sinking the high. 

Please dont start. 

[Mucka]

Nothing set in stone yet. Maybe in another 24h, but probably not. 

Edited February 17, 2018 by Mucka

[Met4Cast]

ICON is cannon fodder anyway.. Never liked it!

[bluearmy]

12 minutes ago, frosty ground said:

No issue if you have the jet swinging round the high driving them west thou surely. 

Let’s hope it all aligns so we don’t need to find out the hard way ........

[Nick F]

17 minutes ago, bluearmy said:

And another thing ........ someone asked before about these desperately low uppers approaching the north sea and how they are likely to be moderated on their crossing. 

Normally the models tend to overdo the uppers out at days 8-10 too, before moderating them. So I'm always skeptical that we'll see -15C uppers crossing the N Sea towards us, though in the past it has occurred on rare occasions and there is a pretty impressive cold pool expanding westwards across NW Russia and into NE/E Europe in the reliable timeframe, which makes it seem more plausible given there'll be little moderation over land before it crosses the N Sea, which will be reaching it's coolest point of the year in next month anyway. 

Edited February 17, 2018 by Nick F

[pureasthedriven]

7 minutes ago, Mucka said:

Nothing set in stone yet. Maybe in another 24h, but probably not. 

That is an astonishingly large PV in the mesoscale aspect of things, no? Dubious. 

[Man With Beard]

23 minutes ago, bluearmy said:

There remains an eps cluster bringing the cold pool at days 8/9. Its still on the table but the day 5/6 option has definitely slipped to our south. We seem to have the deep cold arriving day 8 or day 10. (Or maybe later if we miss these - eps show 40/50% likelihood of sub -10 c uppers in the 9/11 day period. 

BA I went through the individual ensembles and actually I think the cold could be "in" as soon as D6/D7 - plenty of runs in minus double figures at 850hpa by then. There are about an equal number of runs with uppers over +5 between D6-D9, though!! The easterly looks good now but as far as temps are concerned, I don't think anyone should take the output as anywhere near gospel yet.

[Deep Snow please]

1 minute ago, Man With Beard said:

BA I went through the individual ensembles and actually I think the cold could be "in" as soon as D6/D7 - plenty of runs in minus double figures at 850hpa by then. There are about an equal number of runs with uppers over +5 between D6-D9, though!! The easterly looks good now but as far as temps are concerned, I don't think anyone should take the output as anywhere near gospel yet.

It could be but it could also be much later using that logic, I certainly wouldn't be going into the coming model runs expecting a trend to the incoming cold being much sooner than originally anticipated. I'm sure there's a random unincluded outlier that has cold in at D3 but we can't expect that to happen.

[karlos1983]

I think we will allow the ICON a little wobble following its consistency over the past few days. It’s not disastrous anyway. Luckily it’s stopped at +120 ?.

its allowed a night on the razz! 

 

[Deep Snow please]

1 minute ago, karlos1983 said:

I think we will allow the ICON a little wobble following its consistency over the past few days. It’s not disastrous anyway. Luckily it’s stopped at +120 ?.

its allowed a night on the razz! 

 

It must have been invited to Steve's stag.

[karlos1983]

2 minutes ago, Deep Snow please said:

It must have been invited to Steve's stag.

Ahhh that’s the pope!! What an IKON! 

[Frosty.]

I have faith in the Ecm..the 12z ensemble mean becomes excellent in terms of increasingly cold Easterly winds bringing snow showers in from the North sea and widespread penetrating frosts!

[bluearmy]

23 minutes ago, Man With Beard said:

BA I went through the individual ensembles and actually I think the cold could be "in" as soon as D6/D7 - plenty of runs in minus double figures at 850hpa by then. There are about an equal number of runs with uppers over +5 between D6-D9, though!! The easterly looks good now but as far as temps are concerned, I don't think anyone should take the output as anywhere near gospel yet.

Like the 18z then .........

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

Looking a bit shortwavey 

[Snowman.]

GFS has -8s flirting the SE at 126 already. 

[The Eagle]

Looks good so far.

[chionomaniac]

5 minutes ago, bluearmy said:

Like the 18z then .........

Love the angle of WAA on the 18Z - should get that cold air in quicker

[Met4Cast]

Much, much much better GFS. Easterly and cold in much earlier!

 

[ICE COLD]

6 minutes ago, bluearmy said:

Like the 18z then .........

Yep more of an easterly than south easterly. 

[Mike Poole]

These Easterlies are really like pulling teeth - except the tooth never comes out, but the pain continues nevertheless!  

But we're getting there, GFS looks a good run to me, here at T138:

[chionomaniac]

Just look at this. You may as well put a brick wall up to the Atlantic. Perfect imo

The jet cannot cross this...

One of the best charts you will ever see at 5 days

[Sweetdream]

It’s these short waves that always scupper the easterlies. We have been here many times and counted down to within the reliable  only to see Europe go into the freezer with heavy snow and the British isles to get the dregs.