Model output discussion - 1st December onwards

[Winter Cold]

Hi Everyone

Still hard to make a final call isnt it for the weekend and into early next week. It looks at the minute like were going to miss out on snow by just a fine margin. Agonising really!

Just looked at the met office website for my nearest location (Ranmoor @ 200m asl) and its showing temps between 4c and 6c for the period Friday to Monday. I believe their website pulls through raw data from the UKMO model?

GFS ensembles also showing a temp range of similar values:

  

I suppose the positives to take from those though are that fact that weve certainly seen an end to the mild theme and the temps are low single maxs right through to mid Jan on the mean, with a few colder members there! (some milder too of course) and also the mean T850s sub zero from the weekend onwards.

Always the chance that some snow could crop up

[nick sussex]

39 minutes ago, karlos1983 said:

Question- do we pay more attention to the GFS or Parallel ?

The one that has the coldest outcome! lol

 

[karlos1983]

Just now, nick sussex said:

The one that has the coldest outcome! lol

 

Ha ha, yeah that works.

wasnt sure if there were any verification stats?

[nick sussex]

8 minutes ago, karlos1983 said:

Ha ha, yeah that works.

wasnt sure if there were any verification stats?

I think its called the GFSX here:

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/

On a different note the ECM T120hrs postage stamps don't inspire much confidence in terms of what will happen to that low. Theres some much better than the operational run, some similar and some stinkers aswell. Looking at those I think the De Bilt ensembles are still going to show a cluster colder than the operational run.

Edited December 29, 2015 by nick sussex

[swilliam]

Still plenty of cold options on EC ensemble with the OP near the top

[mcweather]

Some excellent posts in here today. As Man with beard has shown a few posts back the gfs is all over the place with its possible outcomes.

Nick Sussex as always keeping us informed of thoughts from across the pond on the all important developments there

and of course Tamara's superbly written piece looking at the global picture explaining  in detail why we,ve had what we,ve had so far and how that may well be about to change.

I would caution about getting to hung up about trying to get this first attempt at an easterly to deliver the goods. (Much though some cold, frost and snow would be more than welcome after the dismal grey and wet rubbish we have had to endure for nigh on two months)  From what I can glean from those far more expert than myself  this is just the start of the process that may at some point down the line deliver a genuine extended cold and /or snowy spell to the UK.

In some ways I am starting to get a feel of January 1978 about the upcoming month with GP suggesting that we should initially look North west for the change to more seasonal conditions. During January 1978 a general west to south-westerly regime started to become more north westerly as lows started to move southeastwards across the UK. There was one memorable exception where a depression moved more west to east and produced an exceptional blizzard that buried much of Highland Scotland around the 28th Jan. Thereafter a more nw/se line resumed and I remember moving house on the 31st Jan with heavy sleet falling even down here in coastal Dorset. This of course being brought about by the subtle but increasing influence of high latitude blocking.

 

A week into Feb and the high latitude blocking really took over and the middle two weeks of February brought and extended cold a very snowy spell to Scotland and much of eastern and southwestern England a spell which culminated in the great southwestern Blizzard on the 18/19Feb ( the third deepest snowfall of the last 150 odd years).

Here's hoping that the the changes now happening will go on to lead to something similar.

 

[A.J]

so then, to summarize the model outputs today taken into account the underlying drivers & variables...

it might get cold.....................then again, it might not 

the answer?....phone a friend or 50/50 

[winterof79]

20 minutes ago, mcweather said:

Some excellent posts in here today. As Man with beard has shown a few posts back the gfs is all over the place with its possible outcomes.

Nick Sussex as always keeping us informed of thoughts from across the pond on the all important developments there

and of course Tamara's superbly written piece looking at the global picture explaining  in detail why we,ve had what we,ve had so far and how that may well be about to change.

I would caution about getting to hung up about trying to get this first attempt at an easterly to deliver the goods. (Much though some cold, frost and snow would be more than welcome after the dismal grey and wet rubbish we have had to endure for nigh on two months)  From what I can glean from those far more expert than myself  this is just the start of the process that may at some point down the line deliver a genuine extended cold and /or snowy spell to the UK.

In some ways I am starting to get a feel of January 1978 about the upcoming month with GP suggesting that we should initially look North west for the change to more seasonal conditions. During January 1978 a general west to south-westerly regime started to become more north westerly as lows started to move southeastwards across the UK. There was one memorable exception where a depression moved more west to east and produced an exceptional blizzard that buried much of Highland Scotland around the 28th Jan. Thereafter a more nw/se line resumed and I remember moving house on the 31st Jan with heavy sleet falling even down here in coastal Dorset. This of course being brought about by the subtle but increasing influence of high latitude blocking.

 

A week into Feb and the high latitude blocking really took over and the middle two weeks of February brought and extended cold a very snowy spell to Scotland and much of eastern and southwestern England a spell which culminated in the great southwestern Blizzard on the 18/19Feb ( the third deepest snowfall of the last 150 odd years).

Here's hoping that the the changes now happening will go on to lead to something similar.

 

 Ahh the memories.How quickly things can change

http://modeles.meteociel.fr/modeles/reana/1978/archives-1978-1-1-0-0.png

 

Edited December 29, 2015 by winterof79

[shaky]

Very good to see that the ecm operational was one of the warmer runs!!fingers crossed for a better run tomorrow morning!!lets see what the gfs 18z brings!!

[Ali1977]

So, nothing looking great in the short term - although more seasonable. Interesting into mid Jan with the PV well and truly on the breakdown. Late Jan and the rest of winter could be good for coldies???? Is that about right?

[mcweather]

6 minutes ago, winterof79 said:

 Ahh the memories.How quickly things can change

http://modeles.meteociel.fr/modeles/reana/1978/archives-1978-1-1-0-0.png

 

yes great memories WO79 and that chart was just the start of it.

[lassie23]

1 minute ago, Ali1977 said:

So, nothing looking great in the short term - although more seasonable. Interesting into mid Jan with the PV well and truly on the breakdown. Late Jan and the rest of winter could be good for coldies???? Is that about right?

Over on weatherweb Tv they are not expecting any prolonged cold in January. It will be a mostly mild month with brief shots of cold. However, it's February that is of interest to them. This is when they are expecting a prolonged, bitterly cold snap to occur. So far they have predicted a mild stormy winter, so they could be right. Not sure if any long range models are seeing this too.

[four seasons in one day]

2 minutes ago, lassie23 said:

Over on weatherweb Tv they are not expecting any prolonged cold in January. It will be a mostly mild month with brief shots of cold. However, it's February that is of interest to them. This is when they are expecting a prolonged, bitterly cold snap to occur. So far they have predicted a mild stormy winter, so they could be right. Not sure if any long range models are seeing this too.

Noted cheers. Any update at a later date regarding Spring appreciated. Apologies if reply in wrong thread, thanks.

[winterof79]

A prime example of the PV being obliterated in January

 

May the forcing be with us

Edited December 29, 2015 by winterof79

[nick sussex]

I think the uncertainty re the low should be resolved tomorrow morning given the differences upstream start showing up pretty early.

In terms of the USA State forecasts they're being rather cryptic however looking at when they expect the Arctic air to depart from the ne USA the GFS looks too fast here which suggests its being too progressive and flat.

Although the ECM didn't really deliver it was closer to the UKMO in terms of the angle of the low near the UK at T120hrs, its just the upstream pattern which caused the underwhelming T144hrs output.

The biggest difference in terms of evolution would however be if we could see what happened next on the UKMO T168hrs, the upstream pattern could see the UK low clear the low heights attached to Greenland and this could deliver that deeper cold towards the UK.

I think at this time if we take a blended approach with a middle ground solution then perhaps not the deep cold but a better chance of some frontal snow for some areas.

Edited December 29, 2015 by nick sussex

[M1245]

It seems as though this cold spell keeps getting pushed further and further back. It was end of December a while ago then it was middle of Jan and now that seems to be getting pushed back again and some are talking about February. 

 

Won't be long and I'll be getting the BBQ out☀️

 

On on a serious note can someone enlighten me as to what the difference is between the likes of GFS & ECM. Sorry for the stupid question but extreme novice here?

 

Cheers

[The Enforcer]

On 28/12/2015 at 8:12 PM, The Enforcer said:

On 27/12/2015 at 7:46 PM, The Enforcer said:

What might the current ECM T+240 look like by the time it reaches T+168?

Now at T+216:

Better or worse? I certainly don't like the appearance of that mild sector approaching the south-west, prompting an early *Mild Sector Alert*.

Now at T+192:

Worse. There is a bigger mild sector, the polar continental air is not over any of the UK and over Scandinavia the cold air seems to be circulating north-westwards, rather than south-westwards in the direction of the UK as previously. Even the polar maritime air to north-west is a bit further away too.

These ECM operational runs are not moving in the right direction, but at least there is still plenty of uncertainty.

Edited December 29, 2015 by The Enforcer
Lots of mistakes, plus got east and west mixed up.

[Timmytour]

36 minutes ago, winterof79 said:

 Ahh the memories.How quickly things can change

http://modeles.meteociel.fr/modeles/reana/1978/archives-1978-1-1-0-0.png

 

With the mild and wet run up to the end of the year, as there was in 1954, I wonder whether the first three months of 1955 might give a pointer as to where this winter might end up (from an optimist's point of view)

The situation as had developed by 4th Jan 1955 does not seem to be  a million miles away from a couple of the better (from a cold-loving perspective) evolutions that current modelling has come up with for the same time frame....

[johnholmes]

On 12/16/2015 at 5:41 PM, Glacier Point said:

 

No idea why this will not delete?

unable to use PC as mouse and PC locked up after 20 mins work, tried for another 20 mins to post but no go, will try and post tomorrow, no big deal for folk but b annoying to me

good night

did try that L but it would not clear it, this might be my mouse issues though, currently working after a fashion but dare not trust it with copying and pasting into here which is where I was when it went awol earlier. Will try to post in the morning, as the outputs post 5 days, from any model, are very interesting. No one person will be right in their interpretation of whichever model or combination of models they use or what prediction they make from them.

Interesting to try though, we all have our favourites, going before the b mouse acts up again!

 

Edited December 29, 2015 by johnholmes
edit - deleted it - look for the little arrows at top left click on them then press delete

[Singularity]

Tamara's done a great job of summarising the reasons why the potential for a significant period of cold, snowy type weather affecting the UK at some point in the next 30 days or so has risen to levels which IMO have not been seen since late Feb 2013 (prior to that crazy cold March). Thanks as always to her for letting us in on her well-informed thoughts 

Having watched the cold outbreaks of 2008/9, 9/10, Dec 2010 and March 2013 unfold in the models, this is what I've concluded about model and forum behaviour:

Typically, the models struggle a lot in the longer-term when the potential has reached such levels. Usually we see them spending some time failing to effectively produce the feedbacks that carry us toward a cold spell, after which they - sometimes suddenly - 'smell the coffee'... only to start jumping the gun and coming up with mouthwatering outcomes that turn out to have been a bit too soon with some complications to get past first. Then comes the 'refining' period, during which enthusiasts agonise over run-to-run changes in the details despite knowing that really it should be left until very short range indeed before drawing ultimate conclusions. Eventually, the cold, snowy potential is realised to some extent or other. All too often we're left looking back on what it could of been and wondering why it had to be watered down so much - but sometimes we get the full-monty and it's a joyous period to be on the forums.

 

This is just a heads up as to what may well be on the way again in Jan-Feb 2016. Having said that, the models may do a better job with the changes this time around given the upgrades they've had since 2010 for example. After all, they handled March 2013 very well indeed, with remarkable consistency from run to run being one of the key aspects I can recall.

Some big mistakes are still being made these days though. Among the largest I know of in recent times is with regard to the AAM state; GEFS in mid-Dec were suggesting -ve AAM tendencies by late month, yet we've ended up a long way +ve. Laughable really, but almost entirely down to a failiure to spot the propagation of tropical convection through the Pacific in advance.

For those who can read it, here's the latest GWO outlook from GEFS... very, very positive indeed:

With signs of another cycle to follow mid-Jan, it seems that the undesirable scenario outlined by Tamara isn't being put on the table by that model at least. If the AAM can kick back up as high as in the next few days during mid-Jan, I can see that being enough to blow the vortex apart, despite its strength.

It's been a long time but I'm feeling that slight buzz of anticipation at last. Now to sit on it until mid-Jan because I like to keep my hopes in check until confidence levels are into the high range, for the sake of mental stability 

 

[shaky]

Changes as early as 90 hours this run!!shortwave further south and west again compared to 12z!!!

[nick sussex]

GFS 18hrs run increasing the amplification upstream, backtracking now from its flatter 12hrs solution.

[knocker]

Frank continues to rapidly deepen in east NATL in poleward exit region of 250-hPa jet:

http://www.atmos.albany.edu/student/abentley/realtime/europe_mslp.php …

[chrisbell-nottheweatherman]

Just now, knocker said:

Frank continues to rapidly deepen in east NATL in poleward exit region of 250-hPa jet:

http://www.atmos.albany.edu/student/abentley/realtime/europe_mslp.php …

Thanks for the update.  Most concerning given the vulnerability of large swathes of northern England at present.

[Geordiesnow]

Got to say, I think the likely hood of any undercutting and easterly flow has backtracked on recent runs, it seems a slight missed opportunity at 96 hours where there is an attempt at an undercut but a rather lame one in fairness when there was a proper scandi block but then after that, the block gets split by a shortwave and it looks a rather complicated way to even get any cold weather from the East from then on in.

The more concerning aspect is the potential for yet more persistent rainfall which in this type of situation is quite likely. The only difference is it will be a bit less mild than previously. 

The only cold that will occur will be this Thursday into Friday, some areas could see an Air frost to start the new year.