Model Output Discussion

[Harsh Climate]

lol http://www.wetterzentrale.de/pics/Rtavn2882.png This would bury the midlands in record snowfall!!

[patneve]

haha 276 hrs = 30 cm of snow for Dublin ohoh silly GFS

[nick sussex]

The MJO which had weakened looks to now be heading for phase 8. This is good news, though waiting to see what GP makes of this.

http://www.cawcr.gov.au/bmrc/clfor/cfstaff/matw/maproom/RMM/phase.Last40days.html

Edited December 8, 2009 by nick sussex

[mountain shadow]

The GFS is now getting the wobbles as the timeframe for change gets nearer, now I suppose it's time for the ecm to step up and bring the beasterly roaring back.

Perhaps your getting the wobbles, the GFS certainly ain't with output like this. If that's a wobble then lets have some more. Imagine the snowfall on the boundry

http://209.197.11.171/c9s4a5k3/cds/gfsimages/gfs.20091208/12/276/h850t850eu.png?dopvhost=charts.netweather.tv&doppl=841a626ccf04e0d9cf54e0891e91ebc2cf54e0ad&dopsig=1df201239bbec677dfba50df41b5a84a

[kold weather]

Very big snow event on the 12z, would be a pretty memorable type event if that was the case but we shall see.

I can't say I have a liking for this run however, the big low ends up coming a little too soon before we get really established into the cold air...

[Geordiesnow]

I wonder what people would of say about this run if we didn't see the 06Z run, i'm pretty sure they would fairly happy with it.

Problem is that most runs don't actually bring in an full on easterly, it's been mostly half hearted attempts so as i said in my previous post, whilst i think an easterly is getting more likely now, i am not too sure if it's going to be an easterly that is convective or not.

12Z run is okay but the link up between the euro high and the Arctic high could of course be better.

[patneve]

'Tis a messed up run, I'm pretty sure the 18z will change things around again anyway!

[Duane S.]

Big difference between the 12z and the 06z is that by +300 la la land, the 06z had the azores high ridging up ready to bring back southwesterlies.

Just another variation on the theme, I see no disaster here

Edited December 8, 2009 by s4lancia

[glasgow-guy]

Perhaps your getting the wobbles, the GFS certainly ain't with output like this. If that's a wobble then lets have some more. Imagine the snowfall on the boundry

http://209.197.11.17...fba50df41b5a84a

am i right and thinking this model now shows any event back north east?

[karyo]

The problem with the 12z is that it takes so long to bring the proper cold to the UK (not till 240 hours) that many things can go wrong till then.

We want the cold spell to come nearer, not get delayed!

Karyo

Edited December 8, 2009 by karyo

[NorthantsSnow]

lol http://www.wetterzentrale.de/pics/Rtavn2882.png This would bury the midlands in record snowfall!!

It's a bit marginal- but yes, somewhere would see severe snowfall on that chart. Probably a bit further north than you suggest with it falling as rain in the south.

[Snowaddict]

The main thing is that the Easterly evolution is maintained solidly on the 12Z GFS Operational run this afternoon.

Parallel run is much more consistent in relation to the evolution, with that perfect heart shape at T+150 and widespread uppers of -5 across the UK:

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=150&mode=0&runpara=1

The evolution is far from finalised and there will be many, many ups and downs yet, but the idea of cold or very cold weather developing over the next week, even less, is fast becoming a solid one.

[Alex95]

No disasters just yet, sure I would have preferred that this downgrade hadn't happened but if you look at the charts side by side for Tuesday from the 6z and the 12z there aren't that many differences, but the short wave isn't quite in the right place anymore. It goes to show how unpredictable the upcoming spell is going to be. We could still be biting our nails at the weekend.

[kold weather]

The evolution is probably a lot closer to what GP would have progged I suspect.

Still I'm not a big fan of the way we have a distinct change in the evolution of the shortwave...if that goes wrong then we have to look back out at 192hrs plus for deep cold and thats even more prone to go wrong of course!

Pretty stunning FI of course, but certainly a rather big downgrade on the easterly compared to the 06z, even the 0z ECM has a stronger easterly at 168-192hrs!

[mountain shadow]

am i right and thinking this model now shows any event back north east?

I don't understand your question?

[weather eater]

For those who want to know 12z parallel is out to 168hrs and is still keen on the easterly.

[mountain shadow]

The main thing is that the Easterly evolution is maintained solidly on the 12Z GFS Operational run this afternoon.

Parallel run is much more consistent in relation to the evolution, with that perfect heart shape at T+150 and widespread uppers of -5 across the UK:

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=150&mode=0&runpara=1

The evolution is far from finalised and there will be many, many ups and downs yet, but the idea of cold or very cold weather developing over the next week, even less, is fast becoming a solid one.

Cheers Snowaddive, I was hoping someone would show the new improved GFS. Just shows nothing is set in stone other than its getting much much colder next week.

[nick sussex]

The problem with the 12z is that it takes so long to bring the proper cold to the UK (not till 240 hours) that many things can go wrong till then.

We want the cold spell to come nearer, not delayed!

Karyo

Its frustrating but at least we're playing with cold variations rather than trying to find a way out of a miserable Bartlett scenario, that MJO though is good news, is it 7 and 8 for aiding blocking near Greenland, 1 and 2 for Scandi high? i think that's it but perhaps GP might be around later to give us the latest on the teleconnections.

[snowmadchrisuk]

No disasters just yet, sure I would have preferred that this downgrade hadn't happened but if you look at the charts side by side for Tuesday from the 6z and the 12z there aren't that many differences, but the short wave isn't quite in the right place anymore. It goes to show how unpredictable the upcoming spell is going to be. We could still be biting our nails at the weekend.

Id rather be having the downgrades today on Tuesday then at +24 hours before the event . Getting them this early means plenty of time left for upgrades.

[kold weather]

It's a bit marginal- but yes, somewhere would see severe snowfall on that chart. Probably a bit further north than you suggest with it falling as rain in the south.

Nope even in the south that would probably be snow, only the SW would see rain from that set-up, dewpoints are below 0C from Kent to Bristol stretching NE...however lets be honest...this has very little chance of happening!

[NorthantsSnow]

The problem with the 12z is that it takes so long to bring the proper cold to the UK (not till 240 hours) that many things can go wrong till then.

We want the cold spell to come nearer, not get delayed!

Karyo

Indeed, especially since any delays will only serve to reduce the potential longevity of any cold with that Atlantic LP set to come rain on the southerners parade...

[Geordiesnow]

The problem with the 12z is that it takes so long to bring the proper cold to the UK (not till 240 hours) that many things can go wrong till then.

We want the cold spell to come nearer, not get delayed!

Karyo

It is getting nearer, problem is on this run at least, the shortwave that does develop heads Northwards consequently there is no trigger low to bring the cold air westwards.

The cold air is all there in europe waiting for a combination of low pressure in the South and high pressure in the North to bring it this far westwards.

Be interesting what the ensembles say for the Shetland isles, hopefully it will be a huge mild outlier as this may mean that pressure will be lower which means the high is further North than it is at the moment.

[Frosty.]

Perhaps your getting the wobbles, the GFS certainly ain't with output like this. If that's a wobble then lets have some more. Imagine the snowfall on the boundry

http://209.197.11.171/c9s4a5k3/cds/gfsimages/gfs.20091208/12/276/h850t850eu.png?dopvhost=charts.netweather.tv&doppl=841a626ccf04e0d9cf54e0891e91ebc2cf54e0ad&dopsig=1df201239bbec677dfba50df41b5a84a

I stand by what I said, it is a big wobble, the risk of this upcoming cold snap failing will increase due to the overall delay in tapping into the icy airmass. I think we have taken a step back since the 06z run.

[Cecil Hogmanay Melchett]

The evolution is probably a lot closer to what GP would have progged I suspect.

Still I'm not a big fan of the way we have a distinct change in the evolution of the shortwave...if that goes wrong then we have to look back out at 192hrs plus for deep cold and thats even more prone to go wrong of course!

Pretty stunning FI of course, but certainly a rather big downgrade on the easterly compared to the 06z, even the 0z ECM has a stronger easterly at 168-192hrs!

Agreed KW.

The 12z operational is a big downgrade imo and has shifted to ecm a hell of a lot today.I had a feeling this was going to happen

so i cant say im too suprised.The pattern looks good for a spell of dry posibly frosty weather at times so

its not all bad.

[snowmadchrisuk]

It is getting nearer, problem is on this run at least, the shortwave that does develop heads Northwards consequently there is no trigger low to bring the cold air westwards.

The cold air is all there in europe waiting for a combination of low pressure in the South and high pressure in the North to bring it this far westwards.

Be interesting what the ensembles say for the Shetland isles, hopefully it will be a huge mild outlier as this may mean that pressure will be lower which means the high is further North than it is at the moment.

It's got to be on the mild side , the parallel isn't great tonight either and topples in FI but still brings us some cold 850's first.