Model Output Discussion 12z 04/12/2012

[Frosty.]

All I will say is hats off to the peeps who said this period would be the change to colder conditions if this is the case. Some really knowledgeable people on her (GP, Chino, Steve M - the resident snowman and John Homes etc)

Like people have said stunning charts from this run - bring on the freezer I say - I am still learning re snowfall etc but temp wise looks like taking a nosedive in the right direction.... ;-))

Someone said they are good charts, thats the understatement of the year, the models have been churning out amazing charts which are just outside the reliable timeframe, I agree with you, bring on the freezer because that's where I think we are heading and hats off to CHIO (Ed) who told me about 6 weeks ago that this type of weather would hit us mid december, almost champagne popping time now but not quite.

Edited December 5, 2012 by Frosty039

[Mac_SE]

Isn't the ECM separated at birth from the 1881 and 1987 charts?

[P-M]

Someone said they are good charts, thats the understatement of the year, the models have been churning out amazing charts which are just outside the reliable timeframe, I agree with you, bring on the freezer because that's where I think we are heading and hats of to CHIO (Ed) who told me about 6 weeks ago that this type of weather would hit us mid december, almost champagne popping time now but not quite.

Exactly - this year, certainly from an IMBY perspective has surpassed 2011 already in terms of snowfall. I am quietly optimistic after tonights run but have to be a tad cautious so that I don't need some prozac by this time next week!!

[V for Very Cold]

if the threads are in meltdown now... imagine the boards if the models came to fruition

[nick sussex]

The thing about the ECM tonight is that the evolution fits in perfectly with the teleconnective thoughts and stratospheric vortex positioning. Even though we know that nothing is nailed until it occurs weatherwise, there is a high chance of the type of easterly developing. From the moment that the forecasts showed the displacement of the strat PV to the Canadian sector and that these looked reliable, the height rises to the NE in some form or another looked a safe bet ( unlike the easterlies called earlier in the autumn).

However, we are now seeing in FI, the next chapter being modelled. That is the transfer of energy from the canadian sector to Siberia.

And of course if this occurs this is likely to prevent any Scandi block drifting east, whilst opening up the possibilities height rises to the NW that the Scand block will retrogress into whilst an undercut is still present.

And that is where I think the models will progress to - another natural progression of the existing pattern.

Chiono the CPC charts look in line with retrogression:

http://www.cpc.ncep....y/610day.03.gif

http://www.cpc.ncep....y/814day.03.gif

And as you rightly mentioned the PV moving to Siberia forces the high westwards not east, so thats a good place to be in if you like the cold and snow.

Edited December 5, 2012 by nick sussex

[Snowman.]

Chiono the CPC charts look in line with retrogression:

http://www.cpc.ncep....y/610day.03.gif

http://www.cpc.ncep....y/814day.03.gif

Wouldn't surprise me with that kind of blocking it's going to need to go somewhere!

[pyrotech]

Obviously met office will have to be more cautious than us on here, but they need to way up cautious v prudent by this weekend if that 12Z ECM was to verify even with a downgrade of sorts.

Models have been showing this trend for a while and many seasoned posters have been saying patience.

Its one mega run but on other side the models and essembles have showed variations of similarity in fi for a while.

Even yesterday on my posts i started quoting a very important name as i think its the most likely way forward for the models.

Daxy Monssaw possibly the most unusual name and rare in the UK but likely to be used 2012.

[Matty M]

ECM EPS to 168hrs is EXCELLANT

MAJOR positive is that control run is very similar to the OP

(all just slight variations of cold!)

Edited December 5, 2012 by Matty M

[chionomaniac]

That is good to see Nick S.

Whilst the dust is still settling I will prepare a new thread and will close this one in 10 -15 mins, so finish off please or hold on!

[cold snap]

Hard to add to anything ,what a amazing day

However lets look at the general pattern we need to keep it like that ,expect a downgrade come morning ,it can't get much better than this ,can it?

[Zenarcher]

GFS ensemble cluster maps show most members agreeing with what the models current show even those that don't they still agree on a blocked set up which is good to see.

[IDO]

ECM mean at T192:

http://www.meteociel...H1-192.GIF?05-0

T240:

http://www.meteociel...H1-240.GIF?05-0

Obviously no where near as cold as the op run:

Edited December 5, 2012 by i'm dreaming of...

[cold snap]

Ens suite epic? Sorry no access ,let us know pretty please?

[snowking]

ECM mean at T192:

http://www.meteociel...H1-192.GIF?05-0

T240:

http://www.meteociel...H1-240.GIF?05-0

Obviously no where near as cold as the op run:

Maybe not but for 51 individual runs to produce THAT!

Pretty epic IMO

SK

[Timmytour]

The thing about the ECM tonight is that the evolution fits in perfectly with the teleconnective thoughts and stratospheric vortex positioning. Even though we know that nothing is nailed until it occurs weatherwise, there is a high chance of the type of easterly developing. From the moment that the forecasts showed the displacement of the strat PV to the Canadian sector and that these looked reliable, the height rises to the NE in some form or another looked a safe bet ( unlike the easterlies called earlier in the autumn).

However, we are now seeing in FI, the next chapter being modelled. That is the transfer of energy from the canadian sector to Siberia.

And of course if this occurs this is likely to prevent any Scandi block drifting east, whilst opening up the possibilities height rises to the NW that the Scand block will retrogress into whilst an undercut is still present.

And that is where I think the models will progress to - another natural progression of the existing pattern.

Chiono....just out of interest....does the ECM ever show an easterly when its not supported with the teleconnective thoughts and stratospheric vortex positioning? Was such support lacking in the famously disappearing easterly of 2005?

My favourite winter of 81-82 was certainly a "two stage" affair with snw arriving around the 8th Dec and staying on the ground till the 26th only to arrive again shortly after the New Year and stay for weeks. If this winter fits that bill, I'll be more than happy!

[Harve]

Ecm 12z is incredible!! People mentioning 2010, would this setup not be colder than 2010 (December) as these synoptics are two weeks further on into winter and darkness? My part of the world in 2010 the cold started Novemeber 27th!

-14c uppers reach East Anglia on the ECM's chart for 15/12. Correct me if I'm wrong, but no uppers below -12c have reached the UK in at least the past 10 years - December 2010's are perhaps the closest. So the potential is certainly there. Given December 1995's ridiculously low temperature of -27.2c in the Scottish Highlands, I imagine uppers must have been very low there. Note that the -20c uppers of 1987, the lowest recorded, did produce exceptionally cold CET days but due to the wind and heavy snowfall, no exceptionally low minima were recorded.

So, it seems slack flows are far more conductive to producing extremely cold temperatures as they often bring clear skies and light winds allowing inversions to last for days, such as in December 2010. But yes, in theory the ECM's run would deliver CET days colder than any, perhaps, in December 2010.

[Jezzer]

I've just had a reply to a tweet that I sent to BBC 5 Live's met man Simon King

"@SimonOKing wowsers indeed! The back end of next week is starting to look rather interesting at this rate!"

[Cloud 10]

The 12z ECM ensemble mean at 168 hrs is a good match for the operational run,note the core of

high pressure near iceland on both charts.

operational.. ensemble mean..

No surprise to see the op run was one of the coldest solutions later on!

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png?6767676767

Edited December 5, 2012 by Cloud 10

[chionomaniac]

New thread here:

Will close this one when I am convinced that everyone has finished posting and we can fish Gibby out from underneath the crush to provide his regular update!

[bradymk]

Great short term ensembles, good support and clustering now below sub zero at least at de bilt.

[cyclonic happiness]

if the threads are in meltdown now... imagine the boards if the models came to fruition

There's be no electricity if those charts came to fruition.

Seriously though, can we take the fall-out if this goes all pear shaped?

Perhaps we should all brace ourselves to come back down to Earth with a bump and the 18z?

I really hope it happens though, the synoptics are the best that could ever be imagined!!

[chionomaniac]

Chiono....just out of interest....does the ECM ever show an easterly when its not supported with the teleconnective thoughts and stratospheric vortex positioning? Was such support lacking in the famously disappearing easterly of 2005?

My favourite winter of 81-82 was certainly a "two stage" affair with snw arriving around the 8th Dec and staying on the ground till the 26th only to arrive again shortly after the New Year and stay for weeks. If this winter fits that bill, I'll be more than happy!

That was too early for my strat analysis. That started 2008.

[bluearmy]

Cant believe the ecm op is a temp outlier at ay 10 !

[khodds]

Gibby not updating tonight, he's back tomorrow - see his post from this morning

[Methuselah]

All beware the way-of-pear!