Model Output Discussion - cold spell to end Autumn

[karlos1983]

16 minutes ago, Man With Beard said:

Always something for fun on these ensembles!! Hope is a wonderful thing, we need a lot of it on the south coast...

But like I said earlier, the snow envelope is currently very wide for T168 (including a "no snow" envelope, of course)

Yep, I do think the picture will become a little clearer on the 12z though (without pinning down any detail), either the ECM will move toward the GFS or vice versa, I strongly feel it will be the ECM moving towards the GFS this time, would be some climb down from the GFS otherwise.

[bluearmy]

8 minutes ago, Man With Beard said:

Always something for fun on these ensembles!! Hope is a wonderful thing, we need a lot of it on the south coast...

But like I said earlier, the snow envelope is currently very wide for T168 (including a "no snow" envelope, of course)

Which will inevitably be the largest ! 

[Turnedoutniceagain]

24 minutes ago, karlos1983 said:

If member 37 were to come to fruition, the Home Counties folk won't be opening the front door of their house, never mind driving to work 

 

Mehhhh.......it'll rain

[Methuselah]

Right then, what have we here:

Snow in the North? Aye.

Snow in the Northwest? Aye.

Snow in the Midlands? Aye.

Snow in eastern coastal regions? Aye. 

Snow in the Southeast? Aye.

And some folks still aren't happy!

[karlos1983]

1 minute ago, Ed Stone said:

Right then, what have we here:

Snow in the North? Aye.

Snow in the Northwest? Aye.

Snow in the Midlands? Aye.

Snow in eastern coastal regions? Aye. 

Snow in the Southeast? Aye.

And some folks still aren't happy!

Yes, south westerners  how very rude 

[Had Worse]

Snowlessteners you mean?

Looking at the charts, I think you'd be extremely unlucky not to see some with the current fantastic set up.

[Midlands Ice Age]

37 minutes ago, Bring Back1962-63 said:

 

 I have come up with 1962-63!!!!  Again, I should remind everyone that it's very dangerous to use analogues as only minor differences can produce very different outcomes. The 1962-63 winter produced some highly unusual synoptics. The winter started off with a number of brief northerlies during the second half of November and early December very similar to some of those we have seen so far this winter. Then there was a period with HP right over the UK with some cold and very foggy weather during the first week of December (this seems less likely for this December). 

Now, any advice on how I can "de-ramp" my reputation!

 

BB62-63..

 A fantastic post...

I have been posting in the winter thread along similar though with 100000 less better terms.

De-ramp!, Not on your life....

 MIA

 

Edited December 4, 2017 by Midlands Ice Age

[musician]

2 hours ago, o0herbie said:

As a long time lurker and non-poster, I'd like to highlight this post as one of the most useful I've ever read on here and implore other posters to use this as an example of something that helps those of us who don't completely 'get it'. Thank you Quicksilver1989

Agreed! it so good to be able to follow what is being said, represented by step by step charts. I'll look forward to further posts from you Quicksilver 1989.

 

2 hours ago, o0herbie said:

As a long time lurker and non-poster, I'd like to highlight this post as one of the most useful I've ever read on here and implore other posters to use this as an example of something that helps those of us who don't completely 'get it'. Thank you Quicksilver1989

 

[Frosty_wsm]

18 minutes ago, karlos1983 said:

Yes, south westerners  how very rude 

Well said, was thinking the same lol

[Paul]

With the 12z's about to roll, can we start to steer this back to the models please. 

And a gentle reminder - the banter thread is a great place for bantering. 

 

Edited December 4, 2017 by Paul

[karlos1983]

the Icon is blowing the low up on Wednesday, we don't really want to be seeing that!!

I think a 950mb low is quite unlikely, bringing 180km/phr + gusts ,

onto the GFS.....?

 

Edited December 4, 2017 by karlos1983

[bluearmy]

33 minutes ago, Ed Stone said:

Right then, what have we here:

Snow in the North? Aye.

Snow in the Northwest? Aye.

Snow in the Midlands? Aye.

Snow in eastern coastal regions? Aye. 

Snow in the Southeast? Aye.

And some folks still aren't happy!

Well I’m in St Albans and looking at the current modelling I’m expecting nothing in the next 7/10 days. whilst there may well be troughs in the flow on Friday, there is nothing solid showing away from the usually prone areas to the n/nw flow. 

As far as the potential slider is concerned there is currently as much chance (if not more), of a system running straight through, w to e delivering some transient snowfall, especially further north and with elevation

not wanting to play scooge on this but some perspective is still required  

If the modelling screams a more than decent chance of a snow event then i’ll be the first to shout it out !! 

[karlos1983]

The icon does end well in regard to the slider low. More GFS than ECM. 

Edited December 4, 2017 by karlos1983
typo

[karyo]

Just now, karlos1983 said:

The icon though does end well in regard to the slider low. More GFS than ECM. 

Yes, that's a re-assuring start to the 12z viewing.

[ZK099]

For what it's worth, last week's cold spell wasn't really modelled to deliver much snow and up until the last minute, uppers looked mediocre. However, in Newcastle in my area at 130m, I had the most snow showers I've seen in years thanks to a late trough in the North Sea. Moral being, even if certain areas aren't modelled to be hit with snow, surprises always pop up, especially in such an unstable flow. So I'd say the vast majority of the UK has a good chance of wintry precipitation from Thursday onwards. 

Edited December 4, 2017 by ZK099

[Mucka]

I have read various comments, over the last few weeks, pronouncing an end to any blocking patterns.

Indeed way back in Nov when the pattern flattened out I was reading how December was going to be zonal.

I know some long range forecasts were going for this and some teleconnections supported it but there has never been a signal for typical zonal conditions to set in within the MO and that is till the situation today.

There is nothing in the output to suggest zonal conditions will take over from mid Dec and even while the MetO forecast was for this to happen the signals withing FI MO were quite different.

All of the longer range signals have been for a continuation of an amplified pattern, yeas waning temporarily at times with milder interludes between, but always with a Southerly jet which always gives a good opportunity for an amplified pattern so long as the upstream forcing is not too great.

Even though the models have occasionally modelled the energy to head NE they have soon corrected and either split energy or sent it SE into Europe - this is a clear sign that the PV is not dictating the pattern and at the moment there is no sign that will change anytime soon.

Some days ago I mentioned a weak signal for an easterly type flow from around mid month but that it went very much against MetO forecast at that time and the seasonal model predictions. Now that is not so much the case and the signal is still there so currently i cannot see where the idea of a mild mobile pattern setting up comes from.

I'm not saying it can't happen, just that there is no signal for it thus far. 

 

[Captain Shortwave]

The model trends have been sit in two camps, the first is the GFS which has tended to undercut the ridge quicker than the rest as seen here.

This has tended to allow the jet to run back oer the top of the ridge and sinking the cut off high, though in this run we get the next low to disrupt south east as well.

The other group is the route with slower disruption but we tend to get the entire trough to go underneath weaker heights as shown on the ECM/UKMO

   

The alignment of the ridge is okay to steer low pressure towards the UK, but runs the risk of milder sectors getting in unless we can correct the pattern westwards a little with slightly higher heights to our north/north west.

A middle ground would suggest a slider low going close to the channel coastline with a more contiental feed ahead of this, I think most would think the middle ground would be the ideal solution with the risk of frontal snow in the south and the chance of showers for eastern parts (more likely NE England and Eastern Scotland). Lets see how the 12z suite goes.

I have found a GEFs member which I think would tick the boxes here

      

It looks a reasonable blend of the GFS/ECM here. I think this would be a good landing zone.

One thing is for sure, Friday looks cold, really cold with temperatures probably scraping 3/4C at best and feeling much colder in a strong north westerly wind.

 

Edited December 4, 2017 by Captain Shortwave

[karlos1983]

extremely cold uppers over Iceland ready to flow south, with some moderating, but compared to the last northerly this looks much much colder!

[ArHu3]

2 minutes ago, karlos1983 said:

extremely cold uppers over Iceland ready to flow south, with some moderating, but compared to the last northerly this looks much much colder!

For the February 2012 and 2013 January coldspells uppers were modeled way too high until right before the coldspells but that was a long time ago and the models have improved of course 

[weirpig]

Well again Wales northwest midlands in for snow Friday Cheshire gap coming into play again . Below chart illustrates it well 

[karlos1983]

has to be said that the GFS 12z regarding the slider low looks not as good as the 06z, more ECM'esk

Still time for it to be ok, next few frames will tell us. (for this run)

Edited December 4, 2017 by karlos1983

[bluearmy]

Gfs makes a big step towards ecm - ecm will only have to make a small step for us to have agreement at day 5 

[Methuselah]

Looking at the run-up to the weekend, this chart is not all bad:

[karlos1983]

UKMO at +120 not entertaining the GFS Slider of the 06z either 

 

[radiohead]

Uh oh. 12Z GFS moving towards to EC.