Model Output Discussion - cold spell to end Autumn

[blizzard81]

Just now, ShortWaveHell said:

Over 200 hours of eye candy charts and you’re worried about the 384hr chart ! Hells teeth 

It goes wrong way before that lol. Anyway, glad it is the 18z and not the 12z or 00z showing this. 

[Malcolm Edwards]

Im not gonna get too hung up on these snow charts.Yesterday it had us under snow all day for friday...now its borderline or maybe miss us...im sure it will change again.

 

[Man With Beard]

5 minutes ago, bluearmy said:

Day 15 cluster shows 2/3 probability of those growing heights to our ne 

...and what is also good is the continuity from the last 3 ensemble runs to this one. Unusual to see such little scatter.

[feb1991blizzard]

Just now, Man With Beard said:

...and what is also good is the continuity from the last 3 ensemble runs to this one. Unusual to see such little scatter.

Yes, i'm beginning to really feel this potential for a potent Easterly late December.

[blizzard81]

5 minutes ago, ShortWaveHell said:

You just got carried away with charts over 300 hours ? This is my WTF moment 

Lol, if only there was an emoji for bless ya! 

[BleakMidwinter]

33 minutes ago, nicktabs said:

Normally over in the regional forums so would anyone mind a quick explanation of what a slider is? Hearing it a lot. Thanks.

Yes, I've spent the last hour floundering around in various threads trying to find out what a slider is... I'd be awfully grateful for a quick explanation, or even just a pointer as to where to find out, please!

[Ice Day]

Control at 144 is on the same page as the Op

Control 

 

Op  

[markw2680]

9 minutes ago, blizzard81 said:

It goes wrong way before that lol. Anyway, glad it is the 18z and not the 12z or 00z showing this. 

Yeah but surely at that far out it don’t matter what model or 12z or whatever shows it, it’s going to change on the next run it’s barely worth even mentioning imo

[Pembroke Dangler]

1 minute ago, Ice Day said:

Control at 144 is on the same page as the Op

Control 

 

Op  

I think the control run is showing a slither more heights to the north if Scotland and the first slider a fairly week affair to the south west and the second slider to head in a similar path to the first mesoscale differences but significant never the less.

[karlos1983]

All good on the ens 

Looking cold all the way to D15

Edited December 4, 2017 by karlos1983

[nick sussex]

3 minutes ago, BleakMidwinter said:

Yes, I've spent the last hour floundering around in various threads trying to find out what a slider is... I'd be awfully grateful for a quick explanation, or even just a pointer as to where to find out, please!

Normally low pressure runs west to east or sometimes sw to ne so the normal zonal pattern in winter rarely engages any cold air over the UK as that's removed before the precip sets in.

Here the low slides se through the UK or just to the west. With a chance it will engage cold air, we have seen of course those Channel Lows in the past but this is equally rare sliding se from near Greenland.

One of the most infamous sliders was 1996 in February , I remember that because all I got in London was a few rogue flakes whilst further west people were sledging!

[tight isobar]

1 minute ago, nick sussex said:

Normally low pressure runs west to east or sometimes sw to ne so the normal zonal pattern in winter rarely engages any cold air over the UK as that's removed before the precip sets in.

Here the low slides se through the UK or just to the west. With a chance it will engage cold air, we have seen of course those Channel Lows in the past but this is equally rare sliding se from near Greenland.

One of the most infamous sliders was 1996 in February , I remember that because all I got in London was a few rogue flakes whilst further west people were sledging!

Got 15cms outta that feature!

?

[Frosty.]

This 18z cold blast is very impressive, lots of snow, ice days, severe frosts..I will love it if this happens!

[Midlands Ice Age]

6 minutes ago, Pembroke Dangler said:

I think the control run is showing a slither more heights to the north if Scotland and the first slider a fairly week affair to the south west and the second slider to head in a similar path to the first mesoscale differences but significant never the less.

I think that the control would be slightly better for snow prospects.

With the first slider being slightly deeper we will have more of an easterly element to the wind before the second one arrives, and less of a southerly..

This would mean snowfall further south.

 

[BleakMidwinter]

3 minutes ago, nick sussex said:

Normally low pressure runs west to east or sometimes sw to ne so the normal zonal pattern in winter rarely engages any cold air over the UK as that's removed before the precip sets in.

Here the low slides se through the UK or just to the west. With a chance it will engage cold air, we have seen of course those Channel Lows in the past but this is equally rare sliding se from near Greenland.

One of the most infamous sliders was 1996 in February , I remember that because all I got in London was a few rogue flakes whilst further west people were sledging!

Thankyou very much - now I can see why people sound excited when talking about sliders! Much more clear now - great!

[Nick F]

Here’s the EC46 Week 3 showing hints of +ve heights / ridging to our N and NE. Now that would be a nice present for Xmas for many on here ...

[Britneyfan]

Annoyingly bbc really are not onboard, showing complete opposite to GFS 

[nick sussex]

Just now, tight isobar said:

Got 15cms outta that feature!

?

I was living in Wimbledon at the time and watched in trauma as a few flakes blew through.

What was remarkable if I put this chart up on first sight it looks a bit underwhelming.

Feb 5th 1996

Next day

The surface flow ahead pulled in some very cold air from the continent, the flow looks south on first sight but was actually se.

It took weeks of counselling to get over the trauma!

 

 

 

[Frosty.]

4 minutes ago, Britneyfan said:

Annoyingly bbc really are not onboard, showing complete opposite to GFS 

They will soon be dragged kicking and screaming if the 18z is anything like right..

It looks like a bitterly cold blast to me

Edited December 4, 2017 by Frosty.

[Spah1]

6 minutes ago, Britneyfan said:

Annoyingly bbc really are not onboard, showing complete opposite to GFS 

Disagree. 

Watch this. 

http://www.bbc.co.uk/weather/features/42231565

 

[nick sussex]

Of course some of the younger members here will have no idea what I'm talking about re the 1996 event. But I know some of the old timers in the se feel my pain !

The key thing with these sliders is some height rise to the ne to help angle the jet se'wards, you don't need a super strong block just even weak heights are sufficient.

Its a juggling act of energy and that's why these set ups are a nightmare to forecast.

They're great fun to watch unfold and it will be stress free this time as I'm a neutral observer!

 

[Chris.R]

Just a question: surely the 18z at t78 is midnight Friday and t84 is 06:00 Friday, not 01:00 and 07:00 as some posters have said, we are in GMT so why add the extra hour? Am I missing something? 

[andymusic]

Just now, Chris.R said:

Just a question: surely the 18z at t78 is midnight Friday and t84 is 06:00 Friday, not 01:00 and 07:00 as some posters have said, we are in GMT so why add the extra hour? Am I missing something? 

meteociel - the fench met office - list is as 01.00 & 07.00

[CanadaAl]

1 minute ago, Chris.R said:

Just a question: surely the 18z at t78 is midnight Friday and t84 is 06:00 Friday, not 01:00 and 07:00 as some posters have said, we are in GMT so why add the extra hour? Am I missing something? 

It's on a french site so it's an hour ahead (CET)

[feb1991blizzard]

Just now, Chris.R said:

Just a question: surely the 18z at t78 is midnight Friday and t84 is 06:00 Friday, not 01:00 and 07:00 as some posters have said, we are in GMT so why add the extra hour? Am I missing something? 

Its because they are on meteociel, I'm guessing because they have strange clock winter time alterations in continental Europe.