Model output discussion 8th Feb - Cold for now, but then what?

[Nick F]

First post of evening focusing on models other than GFS for the next few days, scattered light sleet and snow showers towards eastern parts Thursday and Friday.

But perhaps snow showers pepping up and moving inland across E England  Friday night and spreading well inland toward the west on Saturday as  upper low on near continent and troughing in surface isobars increases lift looking at 12z UKMET-G

500mb vorticity 

12z EC similar

Friday night shouldn't be a problem for snow to lower elevations but during Saturday dew points becoming marginal, so could be a messy mix of sleet and snow inland and probably rain on the east coast.

 

Edited February 8, 2017 by Nick F

[sparky1972]

7 minutes ago, chris pawsey said:

Lol. I'm heading to the drinks cabinet and drinking to the potential snow event / flurries for the weekend 

i need a beer to, just looked outside and its chucking it down with rain, lol

[blizzard81]

The ecm control run for debilt goes cold and quite snowy in the extended. Anybody got any info on that run please?

[Rob Walker]

4 hours ago, ptow said:

Unbelievable for an easterly

Not often in February I remember seeing a moderate easterly touching double figures under leaden skies... 

Edited February 8, 2017 by Rob Walker

[blizzard81]

5 minutes ago, nick sussex said:

Wasn't life simpler when we just had the Radio 4 weather for the week ahead? lol I think when you see how many variables are at play then you can see how difficult it is to isolate out the tipping point. You can't really do a controlled experiment like you do in the lab and that's why because of that background chaos its difficult to forecast a long time ahead. I suppose that's what makes the weather more fascinating and its something regardless of super computers that will still be difficult to accurately forecast at long lead times even well into the future.

Indeed lol, let's just go back to watching countryfile.

[nick sussex]

We don't get a great view on the UKMO T168hrs but theres enough there to suggest it has a Greenland high at  that timeframe, because we know where the high was at T144hrs then it moves this further east. The issue at present is some of that shortwave energy cutting se towards Iberia, we want to see that happen and shortwave energy to detach from the troughing upstream but at least we're seeing signs that pressure will rise to the nw.

 

Edited February 8, 2017 by nick sussex

[Rocheydub]

5 minutes ago, nick sussex said:

We don't get a great view on the UKMO T168hrs but theres enough there to suggest it has a Greenland high at  that timeframe, because we know where the high was at T144hrs then it moves this further east. The issue at present is some of that shortwave energy cutting se towards Iberia, we want to see that happen and shortwave energy to detach from the troughing upstream but at least we're seeing signs that pressure will rise to the nw.

 

As you say, hard to judge, but align that with ECM and we potentially have quite a robust wee cell develop there. With the jet and Atlantic all very quiet, it's very plausible. Also, with the PV relocating to our north east, this has a lot of that dreaded "P" word... Potential!

[Seasonality]

FWIW the pattern of the last 6 weeks or so looks like it is repeating again for central Europe at least. Mild spell is now being lessened in intensity and shortened. Be interesting to see how the next week pans out.

[blizzard81]

7 minutes ago, nick sussex said:

We don't get a great view on the UKMO T168hrs but theres enough there to suggest it has a Greenland high at  that timeframe, because we know where the high was at T144hrs then it moves this further east. The issue at present is some of that shortwave energy cutting se towards Iberia, we want to see that happen and shortwave energy to detach from the troughing upstream but at least we're seeing signs that pressure will rise to the nw.

 

Yep, good spot. Looks like the heights up towards Greenland could be building quite strongly going by that chart.

 

[Trom]

1 hour ago, blizzard81 said:

I don't know whether to admire those who study teleconnections or feel sorry for them lol. So many variables and the smallest of these can cause huge flips in the forecast. Seems almost like a thankless task.

This is exactly the conclusion I formed some time ago. There's no doubt that they have an effect but the correlations between all these measures or at least current understanding of them seems to be limited. I very much admire Tamara et al who are willing to share there knowledge as our understanding of the interplays between them develops. They are often the target of some posters when things don't go to plan but I think we need to accept that our understanding and hence usefulness of these measures In terms of forecasting rather than hind-casting will improve over time.  pioneering is how I see this area right now and I have great respect to those who are willing to share their musings publicly. 

Edited February 8, 2017 by Trom

[JamesL]

Looks like the UKMO says yes to the GH

IMO in 5 days time the charts will be showing our next cold spell but this time I have a feeling it will deliver to more of the UK and be coming from the N or NE and not the E or SE 

[Nick F]

33 minutes ago, nick sussex said:

We don't get a great view on the UKMO T168hrs but theres enough there to suggest it has a Greenland high at  that timeframe, because we know where the high was at T144hrs then it moves this further east. The issue at present is some of that shortwave energy cutting se towards Iberia, we want to see that happen and shortwave energy to detach from the troughing upstream but at least we're seeing signs that pressure will rise to the nw.

 

Problem is that's a west-based -NAO look as has been advertised by recent ops and ensemble means in the 6-10 range, and we are the wrong side of the -NAO trough. The progression from there in the extended EPS mean is to merge the -NOA mean trough with the trough dropping down over Scandi - just hope that's the wrong signal, because that would indicate a return to zonality! 

[winterof79]

Winds picking up Sunday

[MattTarrant]

An early look at the 18z, the more pronounced area of precipitation is more organised on this run. 

Coastal areas will most likely seen rain/sleet. 

P.S A direct link to each of those charts included in your post Nick F would be much appreciated , through PM would be preferred. 

 

Edited February 8, 2017 by MattTarrant

[tight isobar]

Decent. 

More deep cell hp around Iceland. And slight forcing at eastern seaboard on polar-vortex.

18zlooks to be short and long term gain. 

Also better alignment on incoming easterly. 

Some solid support coming for decent waa at Greenland! 

[Nick F]

3 minutes ago, JamesL said:

Looks like the UKMO says yes to the GH

IMO in 5 days time the charts will be showing our next cold spell but this time I have a feeling it will deliver to more of the UK and be coming from the N or NE and not the E or SE 

But if the Greenland high carries on retrogressing into Canada we could end up with troughing between it and us as troughing over Azores links with trough dropping down over NE Europe, see my post above, don't want the ridge to retrogress too far basically ...

[MattStoke]

 18z

 12z 

Colder air hanging on a little longer on this run.

[weirpig]

Will change but quite potent showers moving inland on the 18 z

[JamesL]

2 minutes ago, Nick F said:

But if the Greenland high carries on retrogressing into Canada we could end up with troughing between it and us as troughing over Azores links with trough dropping down over NE Europe, see my post above, don't want the ridge to retrogress too far basically ...

Yes and our cold N or NE being sent into the mid Atlantic whilst we are bathed in mild SW's 

one to watch and a very real option. Better than it showing us in the firing line only to back further and further West. Be nice to see that trend eastwards and give us in the UK winters final hurrah! 

[MidnightSnow]

2 minutes ago, MattTarrant said:

An early look at the 18z, the more pronounced area of precipitation is more organised on this run. 

Coastal areas will most likely seen rain/sleet. 

P.S A direct link to each of those charts included in your post Nick F would be much appreciated

 

Apologies for the IMBY-natured post.. but what areas can expect to see snow if the 18z was correct? Some saying rain/sleet inland, others saying snow.

 

[Ali1977]

5 minutes ago, weirpig said:

Will change but quite potent showers moving inland on the 18 z

This main band keeps moving a little further south each run, places like the Cotswolds could do quite well out of this, especially above 500 feet!!

Edited February 8, 2017 by Ali1977

[weirpig]

1 minute ago, Ali1977 said:

This main band keeps moving a little further south each run, places like the Cotswolds could do quite well out of this!!

Yes seems the further inland the more chance of seeing some snow. Haven't checked the dew points  so not sure what it will be like on the coasts 

[Dennis]

will be the break from that North Low .....?

[MattTarrant]

1 minute ago, MidnightSnow said:

Apologies for the IMBY-natured post.. but what areas can expect to see snow if the 18z was correct? Some saying rain/sleet inland, others saying snow.

 

From seeing the dew points on Saturday I think most inland areas will see some snow, though I think by the middle of the day it will be wetter in nature (Wet Snow below 100m) than through the early morning. There are other factors regarding the complexities of snow forecasting so best messaging a more experienced member. 

[Ali1977]

1 minute ago, weirpig said:

Yes seems the further inland the more chance of seeing some snow. Haven't checked the dew points  so not sure what it will be like on the coasts 

DP are looking good