Model Output Discussion - Colder spell ending, what's to follow?

[warrenb]

4 minutes ago, General Cluster said:

Oh dear... the GFS 06z at t+144 is much too complex for mere mortals like me to understand, so I'll leave the in-depth (it's going to snow -- oh no it isn't -- oh yes it is) interpretations to our resident, self-styled 'big hitters'!

    

I think wet and windy with classic warm sector mild back to average temps would sum it up.

Edited December 11, 2020 by warrenb

[That ECM]

The first signs of what BA was talking about wrt to NE USA?

[BarometerCat]

To my untrained eye it looks very 'as is' up to 144, after then does it not get messy and not reliable?  Would you say no real change next week?  Not massively mild either. 

 

[TSNWK]

Messy.  But I still see evidence of jet heading south east into Europe to our west 

[swfc]

6z brings a decent pressure rise off the esb at the 200 hr mark on gfs. Maybe a decent fi, or not

[weirpig]

Just for discussion   but what a low that is showing on the gfs 

[warrenb]

Just now, weirpig said:

Just for discussion   but what a low that is showing on the gfs 

I was going to comment on that, looking at the 850, it is almost an extra tropical storm.

[frosty ground]

Crazily deep low on the 06z Run but behind that is a ridge that should deliver a FI white x-mass

Edited December 11, 2020 by frosty ground

[TSNWK]

4 minutes ago, frosty ground said:

Crazily deep low on the 06z Run but behind that is a ridge that should deliver a FI white x-mass

I laughed out loud when I read that.. but actually.. this chart is building something nice upstream to compliment low heights over scandi.. maybe

[Vikos]

Aslong as there is no significant change in the rossby wave pattern in any foreacast-modell, there is minimum hope to get some realiable cold spells to mid-europe soon. The jet is not showing any good amplitude changes...

 

We need smthg like this

 

My regards from boring Germany

Edited December 11, 2020 by Vikos
regards

[LRD]

Sigh. All so predictable. Ridging towards Greenland gets easily swatted away by the next low

Azores High set to topple and reinforce the already strong heights developing over Southern Europe. Deep joy

 

 

Edited December 11, 2020 by LRD

[TSNWK]

So on this edition we get a chilly blow in the run up to Christmas maybe a frosty night on Christmas Eve as our foe AZ topples in.. was looking positive around 240 to 300 but flattering took over...

[BarometerCat]

26 minutes ago, weirpig said:

Just for discussion   but what a low that is showing on the gfs 

Is that an example of the GFS 'overdoing' it a bit?  I recall seeing something like this before in FI years ago 

[weirpig]

Will wet and windy  sums up most of the GFS run  more so  in the earlier stages.

Quick look at the short ensembles   a few going for slight rises      

   

[LRD]

Apart from a couple of frames, the GFS 6z is just unrelentingly awful

Topped of with this brown cherry on the turd cake

Time for a rest from this model watching lark I think. Time for a break, time for a...

 

 

Edited December 11, 2020 by LRD

[Methuselah]

And with that GFS run:

    

It's back to my hobby du jour: 

It's nae all about SAD, chaps... what about those us suffering from acute Tom Jones Syndrome!

[SqueakheartLW]

After initial promise yesterday from the GFS 00z and 06z which contained a number of decent colder options the 12z and 18z were such a big let down which means my final totals ended up worse for colder Christmas prospects in the end after the early promise. Here are yesterday's GFS run totals and the change from the day before in brackets

Temps        10/12          Precip        10/12
V Mild         0 (0)             V Dry          0 (+0)
Mild            14 (+1)         Dry             20 (-16)
Average     48 (+3)         Average     73 (+14)
Cold            53 (-1)          Wet             34 (+2)
V Cold        13 (-3)           V Wet          0 (0)
LEADER      AV/CD          LEADER      AV

A rather disappointing trend between the 9th and 10th. An increase of milder and average options at the expense of cold and very cold so a reduction in cold and frosty or white Christmas chances based on this. What makes it even worse so far today is that the 00z GFS runs of today already have the milder option nearly at the same total as the whole of the 4 main blocks of GFS runs yesterday with 3 runs still to go today. Precipitation has also taken a big shift in the direction of wetter and average too at the expense of drier options so looking more like a washout Christmas now.

I am so disappointed with the recent output and I haven't picked out any colder option charts as there's so little to choose from within both the 18z from yesterday and the 00z of today. I have instead shown the 9 charts today of the 32 that have us under a dreaded mild flow for Christmas Day, not what I want to see but is looking more and more likely now

GFS 00z Control Run

A mild chart here but not the mildest of the options. Looks like the standard warm sector between frontal systems and no doubt a cold front is pushing SE on this one clearing out the milder air later on Christmas Day

GFS 00z Member 1

Very dire looking chart for cold fans. A very mild warm sector is moving in for Christmas Day here. No doubt sending day and night temperatures into double digits, booooooooooo.

GFS 00z Member 2

This one is mild too but also looks nasty with that storm no doubt adding to the coldies misery bringing severe gales along with rain and possible storm damage too, merry Christmas everyone

GFS 00z Member 4

A push of milder air here for Christmas Day. Dry for the S and E but the NW could be on for a soaker here with a very high rainfall total possible and a flood risk

GFS 00z Member 5

More widespread mild here but a developing wave to the SW spells trouble for the NW in particular which could lead to enhanced rainfall

GFS 00z Member 6

A large warm sector for Christmas Day here. Not particularly rainy here but just generally bizarre mild temperatures for the big day

GFS 00z Member 12

Uh oh, a December 2015 chart with long fetch S to SW winds. This one has the 5c isotherm easily into the UK with the 10c isotherm threatening from the south. Probably very mild here, maybe even warm and if anyone is looking to breach 20c on Christmas Day then this is the chart for you

GFS 00z Member 20

A mild and dry option for most with double digit temperatures. However the NW is likely to see the cold front arrive later in the day but not soon enough for them to escape a fully mild day

GFS 00z Member 29

The final option is a long fetch W to SW wind option. Mild and cloudy is the most likely result here with high rainfall totals in the NW along the jet stream boundary

Overall not a good sight in the 00z this morning. Hope when I go through the 06z that this doesn't happen again

EC-ENS charts

Time for me to see what the latest 2 ENS charts are showing and the comparison to a year ago too

10/12/2020     12z                           vs   10/12/2019     12z

11/12/2020     0z                             vs   11/12/2019     0z

The ENS charts overall paint a better picture than the 00z GFS did today and also the equivalent 12z GFS from yesterday. The 12z ENS has low pressure over the UK on average with higher than average pressure to our NE as well as way out in the Atlantic too. Overall will be wet but with higher average pressure over Scandinavia a few decent beast from the east options could be there amongst the members at least. The 0z looks better overall if you want cold. The above average pressure is to our NW and the below generally above or to our south. A few Greenland blocking options could be in this collection and a route to Christmas Day cold from the Arctic this time

 

[frosty ground]

Interesting to note that all the Ensembles that bring in sub -5 air are exclusively from the North or North West, A few days agao it was mostly from the north East / East.

We are starting to get movement from west to east, which brings in the risk of toppplers 

[johnholmes]

I know I tend to sound like a stuck record but following one run to the next beyond about 144h is almost a total waste of time IF you are wanting some reliability in the model output. Below 144h then increasingly the new data starts to overide this problem.

Beyond 144h check like with like, 00 and 00 or 12 and 12 on successive runs to see how they compare. IF they look similar then the model may be picking up a reliable signal. Especially if the other models at that range also show a similar outcome.

If you love the chase then ignore the above but try not to be too upset if it often goes t--- up

[chionomaniac]

4 hours ago, TSNWK said:

 

I think what would be good to hear is some updates from a couple of the big hitters who were around start of this week when things at the time were looking more positive for coldies

( invisible wall for anyone?) – be great hearing if they still think we are in the game and if not what has changed as the week progressed to introduce what the models are currently suggesting.

Hi You can always link my name in. As it happens, Thursday is my long day at work, and back early at work today so I have no time other than to mostly cursory glance at the models in the forum. Hopefully will be able to post later and happy to look to see what has changed in the last few days. I am not yet on the zonal band wagon with a lot of promise still ahead.

[MATTWOLVES 3]

Thanks John,and very wise words from an old pro.. Pardon the pun.

Now don't shoot me down for this folks, as I've pulled my neck and can't be doing to much ducking at present. That 46 run last night ends up pretty shocking as we move into January.. That persistent high Heights building around iberia and around Central Europe, coupled with Low Heights south of Greenland are gonna be a major Winter killer if things don't get shaken up sharpish! This is all along way off and could be wrong, those long range anomalies are also pretty stubborn in being a Winter killer.. To make a prediction I thinking we are going to need a major split to bring us some favourable sypnotics!! To put it bluntly we could be waiting several weeks... Patience is gonna be the key! I don't think it looks great right now, but I'm hoping that things may change, in the shorter term to mid term I just can't see it. 

Have a great Weekend.. There is life after the Weather, trust me my wife kept explaining this to me prior to leaving me for the milkman...

[Chesil View]

Meanwhile in GFS ensemble land the end yet again drag the average considerably below the long term mean in time for Xmas.

[Drifter]

I think the best hope for a white Christmas - as things stand, is for a ridge to be thrown up before the big day, bringing in cold air and then a low pressure ‘runner’ zipping across the country with snow to its northern flank. 

[TSNWK]

7 minutes ago, chionomaniac said:

Hi You can always link my name in. As it happens, Thursday is my long day at work, and back early at work today so I have no time other than to mostly cursory glance at the models in the forum. Hopefully will be able to post later and happy to look to see what has changed in the last few days. I am not yet on the zonal band wagon with a lot of promise still ahead.

Thank you  Really keen, like i'm sure many others are here to broaden  our knowledge further  

[LRD]

28 minutes ago, johnholmes said:

I know I tend to sound like a stuck record but following one run to the next beyond about 144h is almost a total waste of time IF you are wanting some reliability in the model output. Below 144h then increasingly the new data starts to overide this problem.

Beyond 144h check like with like, 00 and 00 or 12 and 12 on successive runs to see how they compare. IF they look similar then the model may be picking up a reliable signal. Especially if the other models at that range also show a similar outcome.

If you love the chase then ignore the above but try not to be too upset if it often goes t--- up

Agreed although, funnily enough, over the last couple of days SOME consistency has established in the model output. Which often happens when Iceland Low/Euro High mobility is being modelled!