Model output discussion - after the beast, what next?

[Mike Poole]

1 hour ago, Summer Sun said:

Looking at the GFS mean any snow over the Easter weekend (30th to 2nd) would be in the north and mainly for higher ground certainly so during the day temperatures for the majority are too high.

 

This is not the first time you've made a comment like this, to my recollection. The mean chart is an average of 21 runs so at this time of year it is never going to indicate cold, and is meaningless unless taken in the context of what the individual permutations show.

A much better way to look at what the GEFS is saying is the excellent analysis by @Quicksilver1989 which looks at the probability of various outcomes.

36 minutes ago, Quicksilver1989 said:

Swingometers updated again and it looks like as though we have a stand off for the last week of March.

And I quite Iike the probability plots on Meteociel, here showing probability of 850 temps below -5Cat T192, there would certainly be a chance of snow further south.

The point I'm making is at this timescale the GEFS needs to be interpreted probabilistically.

Edited March 21, 2018 by Mike Poole

[bluearmy]

Gfs 12z and ec 00z ops are very much on the same page right out to day 10 and possibly beyond. Not often you can say that in a non zonal flat pattern - Sod’s law ec 12z will go off on a tangent now !!

[nick sussex]

More energy separation would really help.

Its a shame that chunk of low heights near Greenland can’t just stick there and allow the shortwave to clear properly .

 

[ICE COLD]

T168 ECM and GFS 12z 850s temps . Pretty much on the same page . GFS has the cold air slightly further south . 

[Purga]

If you look at the comparison between the 06z and the 12z ENS on the face of it there is a shift with the mean to closer to average.

However, there is considerable uncertainty and moreover there is a tighter cold cluster grouping with the 12z than with the 06z where the clustering was more around the mean.

A shift then evident of runs going cold and the Op run has gained more support- the mean alone doesn't tell the whole story.

06z                                                                     12z

  

[feb1991blizzard]

5 minutes ago, nick sussex said:

More energy separation would really help.

Its a shame that chunk of low heights near Greenland can’t just stick there and allow the shortwave to clear properly .

 

Yes, or just clear SE and at least open the door to a N'ly, the worst place for it is to West of UK in a football shape.

[nick sussex]

So close from the ECM, more trough disruption se and there could be a snow event.

Its important to get low heights into Southern Europe. Still much better than the UKMO at day 6.

Could still go either way, complex set up. It’s not a more straightforward evolution like the mini beast last weekend .

[Summer Sun]

ECM going for a cold start at least to Easter

Snow to lower levels from about Humberside north

[Mike Poole]

ECM at T216, looks like it supports the idea of a cold blast for Easter, for many:

SS just beat me to it!

 

Think it is going to be another model roller coaster.  I'm certainly on board!

Edited March 21, 2018 by Mike Poole

[DIS1970]

Looks the ECMWF is coming on board for yet another cold east blast.

[nick sussex]

5 minutes ago, feb1991blizzard said:

Yes, or just clear SE and at least open the door to a N'ly, the worst place for it is to West of UK in a football shape.

Now that football decides to anchor itself to the sw!

This run could easily go pear shaped, too much south push and not enough se and not enough trough disruption .

I’m afraid the juries still out .  With a few tweaks this could be a very interesting wintry spell of weather , equally you could end up with the pattern too far west and north and milder air pushing up from the Med.

[Frosty.]

Some say the Ecm 12z isn't that good but comparing like for like, it's a significant upgrade compared to yesterday evening's run in terms of getting colder air from the E / NE to make better inroads further south across the uk with rain turning more wintry and to snow further N & E..as a trend it's a step in the right direction if you're a coldie!❄❄❄❄❄❄❄

[Summer Sun]

ECM ends with an easterly again coldest from around Humberside north still chilly for the south but maybe a bit more marginal for snow by day given the time of year

[bluearmy]

17 minutes ago, nick sussex said:

More energy separation would really help.

Its a shame that chunk of low heights near Greenland can’t just stick there and allow the shortwave to clear properly .

 

Can’t see it accelerating nick

im still looking at he NH profile regarding how long this could last and the way the low Asian heights refuse to phase with the residual Canadian is impressive - left with a cold block Greenland to Alaska 

[Purga]

The Beast is on the way, already into Scotland and the North and sinking South...

Just take a butchers at the NH profile

Lots of very cold air with the GB sticker on its back.

[Frosty.]

To me, this is a much better Ecm run compared to yesterday's 12z..very good, especially further north???❄❄❄❄❄❄❄ its trending the right way!

Edited March 21, 2018 by Frosty.

[nick sussex]

3 minutes ago, bluearmy said:

Can’t see it accelerating nick

im still looking at he NH profile regarding how long this could last and the way the low Asian heights refuse to phase with the residual Canadian is impressive - left with a cold block Greenland to Alaska 

Yes it’s an interesting NH profile .

A bit of luck and the UK could see something quite outlandish for the time of year , equally it could hit the buffers.

Quite high stakes for coldies , I do think this is the last chance for something more widespread.

 

[Chesil View]

Interesting 12z ecm which is not a million miles away from the 18z gfs snow fest of lastt evening.  As Nick Sussex says could go pear shaped but given recent events an upgrade to a more widespread snowy out come would probably be more likely. 

[feb1991blizzard]

9 minutes ago, nick sussex said:

Now that football decides to anchor itself to the sw!

This run could easily go pear shaped, too much south push and not enough se and not enough trough disruption .

I’m afraid the juries still out .  With a few tweaks this could be a very interesting wintry spell of weather , equally you could end up with the pattern too far west and north and milder air pushing up from the Med.

I also notice that football being separated and failing also to phase with troughing in near scandi on the GEFS mean, which was good up until 12z suite.

[feb1991blizzard]

Mind you, that could be a right dumping for SW parts.

[bluearmy]

Eps look a bit west based neg NAO late on (not extended)  - perhaps heading in the direction of the gem?  Spreads on uppers reveals a cluster with a cold easterly flow (more towards n uk as per the op) and also sou’wester close by to our south. Will see how the percentages play out on the clusters later 

Edited March 21, 2018 by bluearmy

[Methuselah]

3 minutes ago, bluearmy said:

Eps look a bit west based neg NAO late on  - perhaps heading in the direction of the gem?  Spreads on uppers reveals a cluster with a cold easterly flow (more towards n uk as per the op) and also sou’wester close by to our south. Will see how the percentages play out on the clusters later 

I must admit BA, that the NAO tells me nothing, nothing that I cannae get from the models themselves, that is...I am lost as to why it gets the amount of attention it does. Am I alone in this...?

[Summer Sun]

ECM 12z mean and Op for London are pretty close together throughout

Lowest is around -5 highest around +2

[Mike Poole]

As we try to firm up on expectations for Easter, I think it's worth posting the FIM9 12z. Experimental model and seemingly only available sporadically, but is here tonight and it's similar resolution to GFS, and uses an icosahedral grid like (recently) much vaunted ICON, so it's worthy of inclusion for those like me who like to view all the op runs as a 'super-ensemble', at 8 or more days out. Here at T210:

Cold incoming from the NNE for Good Friday.  Excellent Friday!

[Tim Bland]

2 minutes ago, Summer Sun said:

ECM 12z mean and Op for London are pretty close together throughout

Lowest is around -5 highest around +2

You might need a trip to Specsavers. Lower runs are around -7c ?!