Model Output Discussion - The Start Of Winter

[Cloud 10]

omeone asked me did the anomaly charts show the start of the cold spell in 2009 or was it 2010, can you tell me which one please, lost your post, I 'think' I have found the data for 2010 in my files for a pdf?

cheers

 

Here are the archives for the CPC charts if helpful John.

 

http://www.cpc.ncep.noaa.gov/products/archives/short_range/srarc.ind.php

[frosty ground]

Ecm looks a bit flat at 240hrs with the high that bit to far west.Still not a bad set up imo but not in line with gfs ete

Looks pretty similar to me.... just further West..... not flat at all

[nick sussex]

ECM delivers a western based negative NAO after a love-in of lows in the Atlantic, the whole thing was painful to watch.

 

This is so vastly different from its 00hrs run that its hard to have too much faith in this. these small lows hanging around the Atlantic are a pain and make any evolution to cold more complicated.

 

So which model has the right trend? I think we're going to have to wait a while longer to find out but one things for sure we don't want a western based negative NAO.

 

I feel a tirade coming on.......

[swfc]

Looks pretty similar to me.... just further West..... not flat at all

The low to the south of greenland is the prob.The gfs ete had the the jet diving south bringing a more organised northerly.Ecm is because of a west based negative nao flatter and not interacting with the azores high

[Buxton Codge]

GEFS 12z not that cold to be honest

http://www.theweatheroutlook.com/charts/gefs/gefsens850London0.png

[Jason M]

ECM delivers a western based negative NAO after a love-in of lows in the Atlantic, the whole thing was painful to watch.

 

This is so vastly different from its 00hrs run that its hard to have too much faith in this. these small lows hanging around the Atlantic are a pain and make any evolution to cold more complicated.

 

So which model has the right trend? I think we're going to have to wait a while longer to find out but one things for sure we don't want a western based negative NAO.

 

I feel a tirade coming on.......

This is my worry. Lots of these have been appearing in the GEFS in recent days. Some further good examples this evening. Like you, I hate that set up as it always feels like the weather gods are laughing at us! Doesn't mean that we won't have more joy later on though into January.

[Abyss]

Can someone summarise were we are currently standing with the latest output? I'm a novice and can't really figure out where we are with different opinions listed here. Thanks

[OldMetMan]

The latest ECM at T240 has that "shape" again - LP strung out across the Atlantic south of 50degN, associated with an extended upper trough aligned E to W. Above this, an upper high stretching from Canada to Greenland, with associated HP.

 

So much depends on cold air extending far enough S, both in terms of its depth and extent. Given enough of a block, and a continuing cold feed down across the Norwegian Sea, LPs in this situation will run NE and glance off the cold block, until finally one runs far enough SE to fully engage the cold air to its N - perfect recipe for a good dumping of snow.

 

Such a situation only rarely works out just right but it does happen and it's a delight to watch. That would be enough for me this winter to see one of those develop, I wouldn't care what happened for the rest of it!!

 

[Weather Boy]

ECM delivers a western based negative NAO after a love-in of lows in the Atlantic, the whole thing was painful to watch.

This is so vastly different from its 00hrs run that its hard to have too much faith in this. these small lows hanging around the Atlantic are a pain and make any evolution to cold more complicated.

So which model has the right trend? I think we're going to have to wait a while longer to find out but one things for sure we don't want a western based negative NAO.

I feel a tirade coming on.......

Hi Nick

I know what the NAO is, but I'm sure I'm not alone in having no clue as to what you mean by "west based" NAO and therefore even less of a clue as to how it is bad for cold!

Help in that regard greatly appreciated - thanks in advance!

Edited December 16, 2014 by Weather Boy

[blizzard81]

I have always been of the belief that the GFS is superior to the ECM with regards to amplification in the north atlantic. Unfortunately, I am not feeling the same degree of confidence I usually feel with the GFS in these situations. The reason being this is not your bog standard azores high ridging up to Greenland affair. It is much more complex than that and one of the biggest flies in the ointment is the refusal of the Iberian high to back down.

[Harsh Climate]

I think some people are looking far too much into specifics regarding the latest output.

 

Only a couple of days ago the models were showing endless zonality with the odd cold shot, now we are looking at a potential greeny block around the festive period. Whether it's a west based NAO or something more lucrative, we will not know until many more runs!  Let's take it one step at a time , I'm very happy with what the models are starting to show now and this isnt just 350h+ it's now <180h (the first page of gfs on wetterzentralle is always good and in the lesser realms of FI .)

 

I swear some just aren't happy unless the runs are 10/10 with -15 uppers and a perfect ending  . 

[Polar Maritime]

Can someone summarise were we are currently standing with the latest output? I'm a novice and can't really figure out where we are with different opinions listed here. Thanks

 

Welcome Bomb, The Models have picked up on a cold spell/snap around the big day. How cold/snowy and for how long is open for question, And will be for some days yet. It's the theme we want to see continue, But there's lot's of uncertainty and mixed signals atm.

Edited December 16, 2014 by Polar Maritime

[Cheshire Freeze]

I personally think that people would do well to remember anything before New Year would be a bonus in this pattern. Once again, a day or two ago Tamara highlighted the likely progression and any decent amplification around Christmas was seen as a bonus. I know people are impatient but let's see how the post Christmas period (the real point of interest) pans out.

It all looks very '09/'10 to me which was a favoured analogue back in October.

Edited December 16, 2014 by CreweCold

[Abyss]

Thanks PolarM

[damianslaw]

Some interesting charts beyond reliable timeframe today, the most common theme is for the atlantic to become quieter next week, that's probably about as much as we can say.

 

Clearly changes are afoot - and the models are probably going to play around with various scenarios over the coming days, some will be cold some will be mild..

 

GFS is noteworthy - a very wintry outlook towards end of next week for the north in particular.

 

I doubt there will be much clear consensus from the models in calling Christmas until the weekend - all very normal given it will be Saturday when Christmas day comes within reliable timeframe.

[knocker]

The last three days of the GEF anomaly starting at T264 on the 14th. Although there are obvious variations with the detail I would suggest they are variations of a theme. The key features today being the eastern US trough and the NE Canada HP but no indication of change in the overall pattern.

Charts courtesy weatherbell

Edited December 16, 2014 by knocker

[bluearmy]

so many options on the table as we get variations on a theme. the envelope getting wider rather than narrowing! will give an assessment after the extended ecm ens are out. in the meantime, currently have a feel for that weakish blocking around greenland (many describing as a -NAO), to deflect the jet on a more southerly track and deliver depressions into a broadly cold nw european torugh. the azores ridge profile and decaying euro heights will dictate how far east the lows get before they turn ne. that sort of says some parts of the uk will see dumps of snow which has seemed likely for a while now, despite no real lead from the met office in that direction. 

 

a proper atlantic block seems unlikely pre new year, given the apparent mobility remaining upstream. however, as tamara says, this could change quite quickly.  all points back to that wide envelope of solutions.

[Gavin Hannah]

I personally think that people would do well to remember anything before New Year would be a bonus in this pattern. Once again, a day or two ago Tamara highlighted the likely progression and any decent amplification around Christmas was seen as a bonus. I know people are impatient but let's see how the post Christmas period (the real point of interest) pans out.

It all looks very '09/'10 to me which was a favoured analogue back in October.

 

 

I was literally just thinking of the 09/10 winter and how it got started just before christmas. Now i think about it, if i remember correctly, it was a greeny high that got us started that year? Could be wrong, but hey, it was 5 winters ago now lol.

[knocker]

Blue-my use of variations on a theme was purely coincidental.

Edited December 16, 2014 by knocker

[Cheshire Freeze]

I was literally just thinking of the 09/10 winter and how it got started just before christmas. Now i think about it, if i remember correctly, it was a greeny high that got us started that year? Could be wrong, but hey, it was 5 winters ago now lol.

Cold-lull-severe cold '09/'10

I certainly wouldn't bet against a repeat of that scenario here.

[johnholmes]

I was literally just thinking of the 09/10 winter and how it got started just before christmas. Now i think about it, if i remember correctly, it was a greeny high that got us started that year? Could be wrong, but hey, it was 5 winters ago now lol.

 

I was literally just thinking of the 09/10 winter and how it got started just before christmas. Now i think about it, if i remember correctly, it was a greeny high that got us started that year? Could be wrong, but hey, it was 5 winters ago now lol.

 

this link may help

http://www.wetterzentrale.de/topkarten/fsreaeur.html

[blizzard81]

If the ECM op is anywhere near the money, it could become very mild as we approach New Year. I am certainly no expert but I would expect the 264hr chart to show a long draw south westerly as the low to our north heads into Scandi and the high to the south to extend east thus allowing the incoming low in the atlantic to head towards north west Scotland. The ensembles will shed a little light on this. If the op is supported, there will be some milder runs post day 10.

[Gavin Hannah]

this link may help

http://www.wetterzentrale.de/topkarten/fsreaeur.html

 

Thanks.  So this is from the 17th of that December.

 

 

Notice the hieghts around Greenland are nice and strong with it extending east and south.  If we get anything like this for Xmas this year... Santa can keep all my gifts lol.

[johnholmes]

If the ECM op is anywhere near the money, it could become very mild as we approach New Year. I am certainly no expert but I would expect the 264hr chart to show a long draw south westerly as the low to our north heads into Scandi and the high to the south to extend east thus allowing the incoming low in the atlantic to head towards north west Scotland. The ensembles will shed a little light on this. If the op is supported, there will be some milder runs post day 10.

 

On the other hand the high pressure belt COULD move ENE and the low COULD swing south (Scandinavian one) and the Atlantic low COULD amalgamate with it to give a very cold flow into the UK?

Edited December 16, 2014 by johnholmes

[shotski]

I think some people are looking far too much into specifics regarding the latest output.

 

Only a couple of days ago the models were showing endless zonality with the odd cold shot, now we are looking at a potential greeny block around the festive period. Whether it's a west based NAO or something more lucrative, we will not know until many more runs!  Let's take it one step at a time , I'm very happy with what the models are starting to show now and this isnt just 350h+ it's now <180h (the first page of gfs on wetterzentralle is always good and in the lesser realms of FI .)

 

I swear some just aren't happy unless the runs are 10/10 with -15 uppers and a perfect ending  .

When I saw the 12z ECM churn out I thought to myself : you've got no fans, you've got no ground, what a s**thole!!!!!

Sorry couldn't resist.