Model output discussion - after the beast, what next?

[Daniel*]

Pub run upgrades the cold pool more extensive area of -16C uppers while being a tad more S.

[Chris.R]

It was about this long before the last Easterly that all the models had that little wobble and then  the day after they settled back again. Let’s give it another 24–36 hours.  

[Mike Poole]

Well cold comes in many forms, we've seen that over the last couple of weeks, GFS 18z at T102 has a purple snake thing about to lick the cliffs of Dover with forked tongue:

But to the more important point re longevity of the spell, it does look like the high is going to sink, T126:

Edited March 13, 2018 by Mike Poole

[bluearmy]

Interesting that ukmo has been pretty solid on it’s track with slight northward correction today whilst the other models have slowly drifted further south with the cold pool. Spreads on ecm show that a northward correction is still feasible. There is currently no reason to think that the cold pool will trend any further south  than ukmo 12z has  it. (Unless you live in cork that is)

Edited March 13, 2018 by bluearmy

[blizzard81]

1 minute ago, Chris.R said:

It was about this long before the last Easterly that all the models had that little wobble and then  the day after they settled back again. Let’s give it another 24–36 hours.  

You may be right. However, the southward shift could gather even more momentum over the next day or two and only the channel islands see anything remotely resembling an easterly. Seen this happen many times over the years. 

[chionomaniac]

6 minutes ago, January Snowstorm said:

The southward correction continues on tonight's 18 run. If this trend continues a lot of the UK and Ireland will not get any easterly (away from southeast uk)

Maybe, maybe not. Though Cork is always the last station on the track whereas easterlies are concerned. 

[SizzlingHeat]

24 minutes ago, ICE COLD said:

You've said that 3 times in 3 different posts , think we get that you want it to push south . But I for one hope it corrects north and prolongs for longer . ?

If it was progged to be more than a 24-36 hour window for some temporary snow followed by a rapid thaw in an ever strengthening sun, then I would be game for it to go north again. However, the sun is now almost as strong as the last third of september and therefore even if there was some last season snow (for some) its gonna be gone in a blink according to most charts from Tuesday onwards. -5c uppers end of march roughly equates to 7 or 8 degrees. If this was mid to end of February, I would be all for it. However its going to be brief by the looks of it and the trend has been south by all major models and therefore any substantial snow which lasts more than a few hours for most people just isnt likely to happen. Just like when the summer is often wet and cool then mid to end of September we have a late surge of heat. Yes it's nice for some, but it doesnt last and the evenings drawing in quickly soon take away the enjoyment of the daytime dwindling sunshine.

Why these charts have to show up when its almost too late. I understand that many significant snow events have happened during march and indeed April but require absolutely exceptional circumstances. Yes -15c flirting with the east in mid to late march is special, its just not going to bring the same temps or dew points as it would if it were to occur in jan or Feb for instance, when the days are shorter and the sun weaker.

The beast from two weeks ago was fantastic for most people who enjoy that kind of weather including myself. However, now the daffs are out and the sun is ever higher in the sky I just want some warmer/milder weather now going into proper spring soon. A few hours of snow and more central heating followed by a rapid thaw is not what im looking for from this time onwards. Those who do then that's absolutely fine too.

Edited March 13, 2018 by SizzlingHeat

[markw2680]

4 minutes ago, Chris.R said:

It was about this long before the last Easterly that all the models had that little wobble and then  the day after they settled back again. Let’s give it another 24–36 hours.  

Exactly what I was trying to say in my post.

[chionomaniac]

The cold pool tickles Cork......

[Chris.R]

3 minutes ago, blizzard81 said:

You may be right. However, the southward shift could gather even more momentum over the next day or two and only the channel islands see anything remotely resembling an easterly. Seen this happen many times over the years. 

Yep it might indeed, or it might not. Will have a better idea in another 24–36 hours as I say. 

[Winter80s]

Totally disagree.  USA sea board further south than us.  Look snow they are getting.  Not a typical winter.  Worse to come or better how you perceive it.  Bring it on.

[cold snap]

Looks like another easterly coming in if you ask me . easterly part 3

[Mr.B]

6 minutes ago, SizzlingHeat said:

If it was progged to be more than a 24-36 hour window for some temporary thaw followed by a rapid thaw in an ever strengthening sun, then I would be game for it to go north again. However, the sun is now almost as strong as the last third of september and therefore even if there was some last season snow (for some) its gonna be gone in a blink according to most charts from Tuesday onwards. -5c uppers end of march roughly equates to 7 or 8 degrees. If this was mid to end of February, I would be all for it. However its going to be brief by the looks of it and the trend has been south by all major models and therefore any substantial snow which lasts more than a few hours for most people just isnt likely to happen. Just like when the summer is often wet and cool then mid to end of September we have a late surge of heat. Yes it's nice for some, but it doesnt last and the evenings drawing in quickly soon take away the enjoyment of the daytime dwindling sunshine.

Why these charts have to show up when its almost too late. I understand that many significant snow events have happened during march and indeed April but require absolutely exceptional circumstances. Yes -15c flirting with the east in mid to late march is special, its just not going to bring the same temps or dew points as it would if it were to occur in jan or Feb for instance, when the days are shorter and the sun weaker.

The beast from two weeks ago was fantastic for most people who enjoy that kind of weather including myself. However, now the daffs are out and the sun is ever higher in the sky I just want some warmer/milder weather now going into proper spring soon. A few hours of snow and more central heating followed by a rapid thaw is not what im looking for from this time onwards. Those who do then that's absolutely fine too.

Lost count of the number of times you contradicted yourself there! Maybe you count them and tell me! ?

[January Snowstorm]

1 minute ago, chionomaniac said:

The cold pool tickles Cork......

To be fair Chino your analysis of the recent strat warming was second to none and have huge respect for your exceptional input.

BUT don't you think this post is a little ott. There is a constant trend today to move things South and NONE of the models have differed. That's all I'm saying and I didn't say southeast wouldn't see snow. Why knock and beat folk who try to call it as they see it?!

[snowray]

Nice FAX chart just out for +T120, not perfect I know but should give us a bit of peace of mind.

Anyway lets hope that the rot south stops with tomorrows runs. 

[Nick F]

Certainly a trend on the 12z EC/GFS and now 18z GFS for drier E/NEly / weaker snow signal over the weekend compared to the runs this morning, most evident from the 12z EC high res - which has shunted heavier snow south across English Channel, Channel Islands and NW France Saturday night / Sunday morning, with the 500mb low/cold pool tracking further south. 

This is why it's not worth forecasting snowfall potential for anywhere in detail this far out, suffice to say there will be some snow showers around. The track of the 500mb low still not nailed by any means, and there is still time for the track further north of the upper low and for lower surface pressure / moisture further north too - which will increase the threat of more widespread snow across parts of England and Wales.

 

[bluearmy]

2 minutes ago, snowray said:

Nice FAX chart just out for +T120, not perfect I know but should give us a bit of peace of mind.

Anyway lets hope that the rot south stops with tomorrows runs. 

Looks like raw ukgm (as does the day 4) 

so I doubt tha5 will allay the stresses

[blizzard81]

Some people on here have been shot down in flames for daring to state what has been the glaring obvious trend of today's runs. Please feel free to hurl insults or sarcastic comments towards me when I state a cold, hard fact about the trend of the day - The centre of the scandi high is now modelled to be MUCH further south west this coming Saturday than what the models were showing yesterday and the day before. This in turn greatly reduces the risk of any meaningful, widespread snowfall this weekend. Not what many on here want to hear but we all know that we simply do not always get what we wish for in this life. 

[chionomaniac]

14 minutes ago, January Snowstorm said:

To be fair Chino your analysis of the recent strat warming was second to none and have huge respect for your exceptional input.

BUT don't you think this post is a little ott. There is a constant trend today to move things South and NONE of the models have differed. That's all I'm saying and I didn't say southeast wouldn't see snow. Why knock and beat folk who try to call it as they see it?!

Thanks, but there is no knocking here. I haven't said that there isn't a trend southwards either. And it isn't off topic but a little tongue in cheek, JS. I hope that you enjoyed your recent snow!

[Derecho]

Right some contradictory posts here which new members must find completely baffling. I'll tackle each issue that has been raised...

1) The easterly is trending south. Somewhat correct

The UKMO hasn't really pulled this further north that often but looking at the GFS runs is there really a trend south, lets see... the below map shows where I think the boundary will be where the air is unstable enough to develop heavy snow showers on midday sunday



Yes there is a trend south though not fully consistent, its tiny differences and the 12z for example saw something slightly further north then the 06z

2) It will be a dry easterly. Incorrect

The 18z still shows a streamer of snow showers in NE England moving down to the Midlands on Sunday. Also the 12z showed something pretty similar.

06z saw synoptic conditions favourable for more widespread snow showers despite slightly more stable heights.

The 00z was admittedly far snowier

Also take note of the curvature of the isobars which is cyclonic over SE England indicating conditions favourable for shower development. The models will underestimate convection.

3) It will be a short sharp cold snap. Correct

It will probably start on saturday and ease on Monday though very cold minina will go on for an extra day or two longer. In the sun it won't feel too bad especially later in the week if rain holds back.

However the cold this weekend will be exceptional. A quick breakdown looks very likely now but will see if the swingometer shows any surprises. I doubt it will, the issue is a lack of instability to our SSW which encourages the high to sink and give way.

A snowy weekend for some! a few members will be disappointed unfortunately but you usually get winners and losers when it comes to UK cold spells. Come mid April I'll be joining summer sun in chasing spanish plumes from the south rather then beasts from the east but its been a good effort so far this March!

Edited March 13, 2018 by Quicksilver1989

[bluearmy]

Six eps clusters as day 4

down to three by day 5 (one of which has cut off upper ridge to our north at 24% though that soon sinks) 

time for sleep and to wait and see where the cold pool is on the 00z suites

Edited March 13, 2018 by bluearmy

[Frosty.]

The Gfs 18z certainly shows a very cold weekend, especially across southern uk which is accentuated by the fresh to strong Easterly winds with max temps barely above freezing for some but there is very little snow, even in the south. That's not to say the next runs won't upgrade but this run shows temps recovering somewhat from next monday.

[feb1991blizzard]

9 minutes ago, bluearmy said:

Six eps clusters as day 4

down to three by day 5 (one of which has cut off upper ridge to our north at 24%)

time for sleep and to wait and see where the cold pool is on the 00z suites

Hmm - I prefer the means at D4 tbh, just a personal view but now the GEFS and EPS mean has pretty much settled on a similar solution, I cant see it being too much different.

And the JMA mean as well.

Edited March 13, 2018 by feb1991blizzard

[Jayfromcardiff]

49 minutes ago, snowray said:

Nice FAX chart just out for +T120, not perfect I know but should give us a bit of peace of mind.

Anyway lets hope that the rot south stops with tomorrows runs. 

Nice trough being shown on that fax chart for the SW, obviously will probably change though over the coming days. 

[Derecho]

Not much change on the swingometer for the 18z's however a few runs do push things a little further south. A small number keep the really cold air away.

In general the OP was probably further south then most other runs with the regards to the impact of the cold pool.

However the control goes along a similar path. Quite a few more widespread snowy runs in there. However we can probably rule out the colder uppers holding on for the whole of next week (by that I mean -5C uppers).