yes rubbish in the long term.Who cares if the minus 10 line comes in,it all be over in 24 hours.

A poor outlook for cold fans, if the gfs is correct,

Yes a really horrific run post day 9 with a deep PV and strongly +ve AO/NAO combo, backed up by many of the ensembles.

 

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GEFS 06z extend the cold snap but there is still a cluster bringing back milder air quickly.

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From +192

Again not a true SSW but definitely a SW - from -64c to -28c in 3 days some 35 - 40c rise in temperature at 10hpa!

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=192&carte=1&mode=7 

What do you make of this? - I did note this is being delayed either way but the SW or SSW is a reoccurring theme each run!?

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GEFS 06z extend the cold snap but there is still a cluster bringing back milder air quickly.

Indeed! Good for now and good thing is that next weekend if will feel more seasonal and the colder spell and intensified! Several ensembles want the keep it cold longer:

 

P 1 - Cold and frosty daytime maxes at or just above freezing at midday. 

 

P 10  -A gentle easterly.

 

P 11: - Battle ground with sub -10 @ 850hpa to our north.

 

 

P 13 - The coldest with -10c @ 850hpa giving us a northerly!

 

P 15 - Tries to build HP over Scandinavia giving us an easterly!

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Yes a really horrific run post day 9 with a deep PV and strongly +ve AO/NAO combo, backed up by many of the ensembles.

 

I still cant believe after what now 14 years on the forum you still haven't fathomed out how a model works especially the GFS.

For 3 days you have been saying the 10 day mean looks horrific - yet if day 1 was 10 day then day 3 should be day 7. Ergo your horrific charts arent getting closer-

This dovetails with the fact that we started out with no sub -6 days then late yesterday transitioned to -8 days & now are flirting with -10c days - With that in mind it doesn't take Sherlock Holmes to deduce that when we max out on uppers - the length of the cold spell will extend as well because your mild synoptics are still stuck at day 10.

How about this headline - 06z Sat GFS ENS mean had london at +8c for around 03rd December- My forecast ( conservative ) will be -6c - Thats a 14 Degree swing to cold all because of model bias.

Just for one season instead of blindly following the GFS at least observe the full model picture.

GEFS 06z extend the cold snap but there is still a cluster bringing back milder air quickly.

 

I fear the milder air will wind and wetter weather will return but at least it gives us some hope of ate least the possibility of the colder snap holding on and becoming a cold spell - albeit a very slim one.

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One or two rather cold days at the end of Nov beginning of Dec is normal fair if it even comes to that. We have seen enough times already this Autumn how an amplified pattern at t168 flattens out by the time you get to t72. This may have legs and stay the course but t144 -168 is at the extreme limit of reliability. 

Many times now we have seen this micro analysis of model output for colder options than what the models are actually showing by one or two  posters especlally  when it comes to continental flow ( east/ northeasterlies) and it has come to diddly squat which had been the general concensus of most of the other posters at the time. As I say lets hope this one has legs.

One or two rather cold days at the end of Nov beginning of Dec is normal fair if it even comes to that. We have seen enough times already this Autumn how an amplified pattern at t168 flattens out by the time you get to t72. This may have legs and stay the course but t144 -168 is at the extreme limit of reliability. 

Many times now we have seen this micro analysis of model output for colder options than what the models are actually showing by one or two  posters especlally  when it comes to continental flow ( east/ northeasterlies) and it has come to diddly squat which had been the general concensus of most of the other posters at the time. As I say lets hope this one has legs.

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@ Steve Murr. Take what Shropshire is saying with a pinch of salt. I think he is playing Devil's Advocate as to what could happen....but the truth is, as ever, noone knows. The 6z GFS Ensembles have trended a little colder and extends it slightly in my view and furthermore there are a number of colder options emerging long term.
I have long since grown out of panicking at every twist and turn of a not infallible set of computer models.
Ian has an agenda to look at worst case scenarios from a Cold perspective. Doesn't mean he will be right or wrong....

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@ Steve Murr. Take what Shropshire is saying with a pinch of salt. I think he is playing Devil's Advocate as to what could happen....but the truth is, as ever, noone knows. The 6z GFS Ensembles have trended a little colder and extends it slightly in my view and furthermore there are a number of colder options emerging long term.
I have long since grown out of panicking at every twist and turn of a not infallible set of computer models.
Ian has an agenda to look at worst case scenarios from a Cold perspective. Doesn't mean he will be right or wrong....

devils advocate is good - not downright ignore :)

UKMO wasn't great so lets see how that lands on the 12z

But the trending thus far has been great !

On the GFS at least, it looks like a classic case of the switch to low resolution results in the mild bump appearing. This is slowly corrected with each run, as that section gradually comes into the higher resolution.

I'll continue to read the GFS upto that point whatever it shows. Largely ignoring the scatter in the low res.

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It’s interesting to see the massive increase in uncertainty (once again) in the 06z GFS ensemble suite. On the t850hPa data there’s is a cross-member spread of 4°C here on the morning of the 1st of December by the evening of the next day that spread has increased to 21°C!

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GEFS 06z extend the cold snap but there is still a cluster bringing back milder air quickly.

yes the cold snap shown there is very much in line with what’s being shown in the NAO graphs:

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_index_mrf.shtml

no denying that or reason to be chastised for pointing it out.

One or two rather cold days at the end of Nov beginning of Dec is normal fair if it even comes to that. We have seen enough times already this Autumn how an amplified pattern at t168 flattens out by the time you get to t72. This may have legs and stay the course but t144 -168 is at the extreme limit of reliability. 

Many times now we have seen this micro analysis of model output for colder options than what the models are actually showing by one or two  posters especlally  when it comes to continental flow ( east/ northeasterlies) and it has come to diddly squat which had been the general concensus of most of the other posters at the time. As I say lets hope this one has legs.

As a general observation this is fine but I’ve not seen anyone commenting on something that’s not in the model output - have you?   There has been perhaps more emphasis on the GFS trending towards a sharper cold spell but nothing more.  The ensembles - both GFS and ECM - have a clear signal for it to turn milder but we’ve all seen the ensembles flip just as much as the operational, so I would emphasise the uncertainty after a short, not unusual, cold spell.

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yes the cold snap shown there is very much in line with what’s being shown in the NAO graphs:

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_index_mrf.shtml

no denying that or reason to be chastised for pointing it out.

Exactly - and worth repeating that the NAO predictions are just a function of the GFS output, AFAIK.

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As a general observation this is fine but I’ve not seen anyone commenting on something that’s not in the model output - have you?   There has been perhaps more emphasis on the GFS trending towards a sharper cold spell but nothing more.  The ensembles - both GFS and ECM - have a clear signal for it to turn milder but we’ve all seen the ensembles flip just as much as the operational, so I would emphasise the uncertainty after a short, not unusual, cold spell.

A good reminder, that; clustering isn't Gospel so we needn't be discouraged, even by a clear group in the Ps trending one way or other, beyond the relatively certain range.

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Actually, looking at the 06z GFS Ens, 9 members now have sub -5 850s out to 4th December. I might have got this wrong, but that looks like a day's extension compared to earlier runs? P6 then goes off on a happy one.

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Extreme ICON to start the afternoon almost a full blown GH at 144 - ❄️🌲

Extreme ICON to start the afternoon almost a full blown GH at 144 - ❄️🌲

Ive started my winter model watching on Saturday and I must say I was thinking yesterday evening  we are potentially on the cusp of something here if those LPs can dig SE into Europe and the jet stays to our south.  Encouraging signs from ICON.  Id say its currently (ahead of 12zs) a 40/60 as to whether in a weeks time we are in a cold spell. Certainly no better odds than that.  A damn sight better than staring down the barrel of certain raging zonality, which we may well be in one week if the milder options win out and pattern flattens.

This evening's full suite of operational and ensembles will be interesting to contemplate, and maybe we will be 50/50 or possibly down to a 20/80.  We shall see. 

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Extreme ICON to start the afternoon almost a full blown GH at 144 - ❄️🌲

It will be interesting to see which if any of the other models go for the ICON scenario!

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