Model Output Discussion 12z 18/10/2012

[Snowstorm1]

I think this run from GFS is further west. Or are my eyes just going funny due to stareing at so much output?

Im thinking the same thing compared to last run which was 06z or are my eyes funny too

[Paul]

Don't forget you can easily switch between the current and previous runs on the chart viewer: (click the prev run button to view the previous run - one good option is to open the same chart types next to eachother and then have one on the previous run and one on the current one)

http://www.netweathe...tion=nwdc;sess=

[shedhead]

I think this run from GFS is further west. Or are my eyes just going funny due to stareing at so much output?

What's further west, the mild air, the cold air, the block or Ireland?

Edited October 22, 2012 by shedhead

[Adam lufc]

Or Ireland lol

[The watcher]

What's further west, the mild air, the cold air, the block or Ireland?

If one is further West, all 3 are. But Ireland.....we are still here in our usual spot.

[shedhead]

The -5c 850mb isothem is still progged to invade most of the UK on Friday..

But then gets promply shoved away early on Saturday.

Thereafter we are looking for a quick reload to bring colder conditions again next week, but the LP progged to be close to Iceland later on Sunday may well delay this southward progression, at least according to GFS.

Cold air struggling to come south, even into next Tuesday IF this is correct.

Edited October 22, 2012 by shedhead

[Gavin Hannah]

The destination of the cold shot is still in the balance. It won't be until wed morning before we get a firm grasp of how the northerly behaves and what is likely to happen thereafter. Prognosis is still looking very good for some frostiness and high level snow. But can we hold on to it for a sustained period? This is going to be an interesting few days.

[SnowObsessor90]

Interesting that we haven't seen anything of Mr Murr since last night, wonder how long it'll be before we see him posting again....

[Eskimo]

Interesting that we haven't seen anything of Mr Murr since last night, wonder how long it'll be before we see him posting again....

Which could mean he's at work lol

[Cheshire Freeze]

Well between the UKMO and the GFS 12z, this 'cold spell', that looked oh so promising, seems to have been reduced to a 24 hour period with uppers at or slightly below -5. By 6am Sat the situation looks like this...

Into FI....this is the sort of pattern we'll enter as we progress through November....

This would be depressing in Jan!

Edited October 22, 2012 by CreweCold

[jethro]

I have never seen such an accurate run........its beautifully spot on

BFTP

How can any run be said to be accurate or spot on until judged after the event?

[Aaron]

Well between the UKMO and the GFS 12z, this 'cold spell', that looked oh so promising, seems to have been reduced to a 24 hour period with uppers at or slightly below -5. By 6am Sat the situation looks like this...

Oh well, at least the cold is going somewhere it is actually useful, Scandi should see widespread snow, not possible here.

[phil nw.]

We have had to delete some off topic contributions.

Let`s keep to model discussions please.

Thanks all.

[Frosty.]

I am not going to fall into the trap of believing individual op runs, this is the problem with following every run religiously, it's a recipe for disaster. I still don't think the models have got a good handle on the end of the week and a lot can still change for the better. BBC weather still say we are in for an arctic blast and not a watered down nw'ly.

[lorenzo]

In regards to the track of that LP over US/Canada and the impact on Greenland heights.

GFS quicker and UKMO slower with the evolution deepening the Low. GEM closer to the GFS solution and perhaps a trend towards GFS with this run.

GFS / UKMO / GEM

This is where the CPC model discussion comes in useful as to which solution is favoured, speaking of CPC pages Tropical Depression18 is worth a watch on the GFS later frames. If the trend for later regarding a blocked outlook to more zonal conditions this could end up a lively visitor.

[Snow and storms]

It is all down the pesky High that is now expected to sit below Greenland. The trend for this over the last few runs is for it to sink further south and maybe slightly east. Pushing the bulk of the artic surge into the rest of euorpe.

It is also beginning to trend towards breaking apart or at least getting pushed around later on which is not so good! I would rather see this high keeps its shape than get an amazing blast of cold weather however I think the two are linked anyways

[Cheshire Freeze]

I am not going to fall into the trap of believing individual op runs, this is the problem with following every run religiously, it's a recipe for disaster. I still don't think the models have got a good handle on the end of the week and a lot can still change for the better. BBC weather still say we are in for an arctic blast and not a watered down nw'ly.

The MetOffice will start to reflect the most recent output in due course. The UKMO model has fallen in line with the GFS and so has the ECM on its 00z run.

[Alan Medlock Valley]

The absence of Steve Murr and a couple of others reflects the slightly poorer model output today. But let's face it it is only October

- we still have a considerable amount of time so no need for people to be downbeat or induce wristslashing.

[Tim Bland]

For me a bit of sleet at the weekend would have been a bonus. What's most concerning is the flip back to a more zonal outlook with highs to our south and an organised PV. Seasoned model watchers will know that this pattern can last for weeks or even months.

[Frosty.]

The MetOffice will start to reflect the most recent output in due course. The UKMO model has fallen in line with the GFS and so has the ECM on its 00z run.

I will reserve judgement until the 00z runs, just some small adjustments and we still have a shot, i'm not convinced it will just be a wishy washy nw'ly.

[Summer Sun]

UKMO 850hpa

UKMO is now falling into line with GFS and ECM by downgrading this cold snap to just a few days max

Pressure starts to rise as early as Sunday

However cold fans don't give up the met office state the following

Some more persistent rain is possible for a time later on in the first weekend (this coming weekend) but the relatively cold and unsettled conditions will return thereafter, with sometimes prolonged wintry showers interspersed with drier and brighter periods

GFS shows another cold burst next week

Pressure then doesn't rise to bonfire night which is well out in FI

Cold fans don't give up there will be many up's and down's over the coming day's

Edited October 22, 2012 by Summer Sun

[Gavin Hannah]

Those lows always chop and change from run to run. It was only a few days ago that the LP in the Atlantic was progged to throw off a shortwave and scupper the entire prospect of a cold snap.

[Cheshire Freeze]

What's most concerning is the flip back to a more zonal outlook with highs to our south and an organised PV. Seasoned model watchers will know that this pattern can last for weeks or even months.

Indeed it can. I don't agree that it's impossible for synoptics to be good from now throughout winter like some have suggested. The general pattern could remain decent from a hemispheric perspective without showing the familiar signs of an organised PV and roaring jet.

For example, Nov 2009 was mild and wild for UK BUT there were signs the atmosphere was primed for blocking to develop...

No deep purples around Greenland.

Currently, if the PV fires up, with little warming of the strat forecast, I fear later November through December could be wet and mild! Matt Hugo has alluded to this over in the strat thread.

Edited October 22, 2012 by CreweCold

[Alan Medlock Valley]

For me a bit of sleet at the weekend would have been a bonus. What's most concerning is the flip back to a more zonal outlook with highs to our south and an organised PV. Seasoned model watchers will know that this pattern can last for weeks or even months.

I remember back in late Oct 2010 early Nov 2010 people in here throwing strops and being downbeat about prospects before Winter had even begun! but look what happened at the end of Nov - a good 90% of people in here did not see that coming until a week or so earlier.

[peterf]

quite a large percentage did though,so not sure where you get the 90% from.some of us just sat back in awe and watched things unfold.