Model Output Discussion - cold spell to end Autumn

[carinthian]

3 minutes ago, frosty ground said:

Looks like Scotland will be under the Arctic air with the rest of the UK on the wrong side.

Without any upper air charts available at 168t its difficult to make a forecast based on that chart. However, looks like a developing low to cross the heart of the UK  towards the end of next week with coldest air to the North ( Scotland at least ) and a warmer sector over Southern England for longest.. Could end up as a snow event for Central Britain and sort of ties up with the Met Office of a renewed Northerly not far away next week after the passage of the short wave/ldepression. Should start to pick this up on fax charts this coming weekend and then only will the UKMO start to mention a possible snow event. Great chart watching this. 

 C

 

[karyo]

3 minutes ago, carinthian said:

Without any upper air charts available at 168t its difficult to make a forecast based on that chart. However, looks like a developing low to cross the heart of the UK  towards the end of next week with coldest air to the North ( Scotland at least ) and a warmer sector over Southern England for longest.. Could end up as a snow event for Central Britain and sort of ties up with the Met Office of a renewed Northerly not far away next week after the passage of the short wave/ldepression. Should start to pick this up on fax charts this coming weekend and then only will the UKMO start to mention a possible snow event. Great chart watching this. 

 C

 

I suppose the ECM gives us a northerly towards the end but it is a short lived affair with the high sinking again.

[karlos1983]

Ok so disappointing viewing overnight, but is it time to give up on the possible next cold spell that the 00z appear to be disinterested in? I don't think so, not yet!!

Above is yesterdays 12z Ensembles, note that on around the 7th is where members start to disagree, some go very cold, some go mild. 

I won't post it because if you want to find them yourself you can (US site), but the ensembles from the overnight runs, show pretty much the same picture, we could have uppers anywhere from almost -10c to +10c from around the 7th. 

So this is far from done either way. I would think we will start to see a clearer picture in the next 24-36 hours or so. I'm not going to stick my neck out and say what might happen, to much noise at the moment to see a clear path forward. But there is still hope for coldies IMHO.

Edited November 30, 2017 by karlos1983

[snowice]

1 hour ago, abbie123 said:

Very interesting model watching over next few days I feel ecm saying yes colder later next week..

It's like chasing shadows all in FI

[carinthian]

Just now, karyo said:

I suppose the ECM gives us a northerly towards the end but it is a short lived affair with the high sinking again.

Karyo, at least you are seeing northerlies for the start of winter. All models flipping at the moment to deal with the cold now taking place in much of the NH. Think JH mentioned already had 4 air frosts in his part of the world and that 4 times the 20 year average for November. So all I see is positive news on most of the models in the reliable time span . Just to highlight some of the intense cold now developing in the NH , a record low of -60c yesterday in a location in Northern Siberia and the ice between Greenland and Iceland is currently only 100km from a bridge , now that impressive for last day of November. Charts look a lot colder to start the winter season for a number of years.

C

[Frosty.]

The fact is the 00z models are showing nothing like the met office update so something will have to give, either the models significantly improve or the MO will shortly water down what they've been saying.

Edited November 30, 2017 by Frosty.

[karyo]

8 minutes ago, carinthian said:

Karyo, at least you are seeing northerlies for the start of winter. All models flipping at the moment to deal with the cold now taking place in much of the NH. Think JH mentioned already had 4 air frosts in his part of the world and that 4 times the 20 year average for November. So all I see is positive news on most of the models in the reliable time span . Just to highlight some of the intense cold now developing in the NH , a record low of -60c yesterday in a location in Northern Siberia and the ice between Greenland and Iceland is currently only 100km from a bridge , now that impressive for last day of November. Charts look a lot colder to start the winter season for a number of years.

C

hi carintian, that's all good but I can't see any relevance in the number of frosts we are seeing (i also had more frosts than usual) with whether there will be a long lasting northerly next week or something more like the ECM is showing?

[karlos1983]

Just to add to my previous comment, The control run looks decidedly cold from the 8th!!! 850's of -7c covering the entire UK, Scotland almost into -11c uppers.  I'm not sure how accurate this site is, so perhaps @bluearmy can confirm?

Edited November 30, 2017 by karlos1983

[Man With Beard]

ECM ensembles - certainly more than half of members have given up completely on a northerly between D6 and D10 this morning. Out to D15, no concrete signal but no sign of any major blocking either in our part of the world. 

I wonder if this is one of those 00Z suites vs 12Z suites situation, because while the past two 00Z ensemble runs have been poor for UK cold, the past two 12Z runs have been much more positive. 

[bluearmy]

7 minutes ago, karlos1983 said:

Just to add to my previous comment, The control run looks decidedly cold from the 8th!!! 850's of -7c covering the entire UK, Scotland almost into -11c uppers.  I'm not sure how accurate this site is, so perhaps @bluearmy can confirm?

Eps control has some cold air filtering south around depressions running nw/se into the sceuro trough 

its a general ens theme this morning

[stodge]

Morning all

More swings on the model outputs in the past 48 hours.

A week or so ago, we were "hoping" for a relatively clean evolution from the current cold spell to another Atrctic outbreak and that would come about as the HP currently to the west of the British Isles retreated NW back toward Greenland allowing the next LP to swing ESE from north of Iceland toward Scandinavia.

Instead the HP is going to slip past the British Isles to the SE and Atlantic energy from quite a long way south will break through and spill over the British Isles leading to a more protracted milder spell probably lasting much of next week.

The Greenland HP tries again to build SE (the ICON 00Z OP run shows this beautifully with its 3-hour steps) and shunts the energy SE out of the British Isles and re-introduces another Northerly incursion.

Moving into mid December and frankly chaos reigns and order is in very short supply. I keep seeing hints of a build of HP to the NE - could this be the HP moving down off the Pole - while the alternative looks to be a stormier spell with LP passing close to or over the British Isles. The PV remains disorganised on much of the output though it has to be said a number of the 00Z OP members do seem to be wanting to restore order by returning it to its usual place.

GP's as always excellent post yesterday has got me thinking though and if I were looking at cold from mid December onward I'd be looking NE not NW.

 

[bluearmy]

Have a feeling we will be talking wedges a fair bit I’ve the next couple weeks 

[damianslaw]

General atlantic pattern remains amplified, with mid atlantic heights and the jetstream split, with equal levels of energy in both the southern and northern arm, hence a wax and waning set up between cold northerlies and milder sinking westerlies, before the pattern re-sets. This has been the theme of the past few weeks, and looks like continuing again next week. We could see an active trough feature develop later next week thanks to shortwave activity, indeed a bit of an explosion of low heights, not too disimiliar to what happened middle of last week, with a marked cold/warm sector boundary, a quick return to colder conditions by the weekend, and possible snow event. This is being shown by both GFS and ECM to some degree, but remains beyond the reliable.

Provided we maintain the split flow in energy in the jetstream, a return to zonal westerly conditions looks unlikely. 

In the short-term a wintry couple of days, snow for quite a few in eastern parts, air frost to welcome winter proper, before a rather drab milder weekend, such conditions continuing through the first part of next week.

 

[Frosty.]

11 minutes ago, bluearmy said:

Have a feeling we will be talking wedges a fair bit I’ve the next couple weeks 

And building blocks and potential etc etc

No beating around the bush, as a hard-core member of the cold cabal / mafia I'm disappointed with the 00z this morning but things could swing back.

Edited November 30, 2017 by Frosty.

[feb1991blizzard]

10 minutes ago, bluearmy said:

Have a feeling we will be talking wedges a fair bit I’ve the next couple weeks 

I was rather hoping we would be talking sledges a fair bit over the next couple of weeks!

[Troubleatmill]

11 minutes ago, bluearmy said:

Have a feeling we will be talking wedges a fair bit I’ve the next couple weeks 

Not had one of them since sadistic steve at school ?

[feb1991blizzard]

Meanwhile this looks a better run, I wouldn't call a pass yet but its possible, developing shortwave near Iceland further south west this time which is a good thing - it means the cold air digs south further West and Earlier.

[weirpig]

Difference again on the GFS   whwere will this take us

[bluearmy]

8 minutes ago, feb1991blizzard said:

I was rather hoping we would be talking sledges a fair bit over the next couple of weeks!

But wedges lead to sledges  !

im not disinterested in the way things are evolving - it may not turn out well for us in the south of the uk re snowfall but suspect there will be a dividing line somewhere 

[Frosty.]

15 minutes ago, feb1991blizzard said:

I was rather hoping we would be talking sledges a fair bit over the next couple of weeks!

 

could the 6z be swinging back colder?..might have to stock up on the essentials

Edited November 30, 2017 by Frosty.

[Scandinavian High.]

More changes will we start see upgrades.?

[feb1991blizzard]

2 minutes ago, bluearmy said:

But wedges lead to sledges  !

im not disinterested in the way things are evolving - it may not turn out well for us in the south of the uk re snowfall but suspect there will be a dividing line somewhere 

I take it your talking thin wedges of heights?

[frosty ground]

Heights further North.....Cold air slowly advancing south

[Paul_1978]

So the 00z GFS shows a deepening low approaching western Scotland at T+168.

By T+186 it take a south-east track into Ireland and into the channel, resulting in a North/North-Easterly wind across the UK by T+201. 

The North/North-Easterly is pretty much gone within 24 hours replaced by a Westerly, before we go into low-res.

Then we clearly see pattern indicative of a meridional Jet Stream which is basically what we've had in the last few weeks. 

So to me we are still stuck in a rut of northerlies coming and going every week or so, but I also feel we are approaching a crossroads where something has got to give. There are goings on in the strat, as well as events in the Pacific which have been mentioned.

One thing is for sure, it's going to make an interesting few days model watching to see which way the cards fall, and who knows which way it's going to go. That's why we are all here. 

But the thing for me is that it's 1st December tomorrow, the meteorological start of Winter. We've had some great model watching recently and it's easy to forget it's actually still only been Autumn.

Edited November 30, 2017 by Paul_1978
Typo

[SMU]

Morning

The 06z ( alligned to UKMO 00z )

looks a fair reprentation of where will end up at day 6/7 with a North south divide & snow possibilities arriving for 'somewhere in the middle'

 

PS - my first snow flurry today - the last day of Autumn!

S