Model output discussion - proper cold spell inbound?

[Day 10]

6 hours ago, Day 10 said:

So another morning of runs are just about coming to an end and the volatile nature of the output continues, hardly surprising giving the nature of the atmosphere right now. Yes the weather is always chaotic so throw into the mix the beginnings of a strong Sudden Stratospheric Warming and the models are bound to struggle.

I expect the output to continue in this vein for a while yet, no despondency from me only intrigue into how everything is unfolding. I think at least another week of rain interspersed with wintry showers or snow for some is on the cards, this weekend being the perfect example, rain in England & Wales today, snow in Scotland/Northern & Ireland and snow showers for some tomorrow.

 

As some have already alluded to the dates of 18th, 19th 20th are when things could become far more interesting as blocking may start to setup somewhere between the North and East of the UK drying things out, but at the same time eventually and hopefully ushering in Winter proper and of course this then brings the threat of country wide snow.

Don't be surprised to one minute see holy grail charts and the next not so good while the models are still getting to grips to this irregular pattern.

I will end on this chart from the other day, not saying this is what we will end up with but it wouldn't surprise me if charts like this pop up again before the week is out.

For once we have a number of signals all heading in the right direction so let's hope we finally hit the jackpot!

Well I must say I wasn't expecting holy grail charts to pop up so soon again but I'm not arguing GFS, fire away and continue to reel them in. Lovely to come in from the match 3 points in the bag and to see charts like these back on the menu, long may it continue.

ECM your turn...

[ICE COLD]

That is a very good set of ensembles IMO . Trending colder ?

Come on ECM make us feel like this ?

Edited February 10, 2018 by ICE COLD

[MR EXTREMES]

Just trying to settle model nerves but yesterday mornings gem model run was the same as today's ECM nightmare run.

But today the gem is a blinder.

JMA last night's run also shows northern blocking in the right place.

Navgem gets there,

ukmo I suspect would get there.

There really is no reason to take this morning ECM as gospel.

Today's gem chart 

Identical to recent ECM runs.

Again this evening could well be a full house from the models nav gem GFS and once again the gem model throws out some wintry weather.

Exactly what I've expected how cold is up for debate,

 

 

 

[Weathizard]

2 minutes ago, ICE COLD said:

That is a very good set of ensembles IMO . Trending colder ?

Lovely cluster below the -5 figure, still a bit of scatter though amongst the other ensembles. I would temper expectations a little, the models can be very fickle and volatile when a warming occurs.

Lots to be positive about but would advise nobody buys stocks in sledges just yet. 

[nick sussex]

Putting aside the medium term, shorter term the UKMO fax chart still shows some possible snow at T72hrs.

Quite unusual to see an Atlantic front surrounded by sub 528 dam, any milder air gets squeezed out and the front seems to slow.

 

Edited February 10, 2018 by nick sussex

[Tamara]

Irrespective of what the ECM goes on to show shortly and irrespective of what my head keeps telling me of how the effects of this SSW could be mitigated,  I am not sure I have seen anything programmed quite like this thing.

Polar easterly reversals are often enough mitigated at least to some degree by other tropospheric drivers, but I am beginning to come to round to thinking this may not be one of them where that happens so easily and its going to take over a lot of the NH for some time.

Its one of those very occasional cases in point where referring to the direction of travel of the GSDM is certainly not the whole story when it comes to tropospheric forcing and the placement of the jet stream, set against such a considerable reversal of zonal wind anomalies coming into the troposphere.

So on that basis, putting aside what my head has been telling me, it could be the case that it would start to be more prudent not to underplay the SSW, than place caveats as to what might mitigate it. On that basis maybe its me who should have a bit of a ramp, and not others who should restrain themselves

However it plays out in terms of what comes out of the sky in the coming weeks - and despite the fact that the actual phenomena of SSW's is not new, this is quite a significant specimen indeed we are watching unfold

[SMU]

2 minutes ago, nick sussex said:

Putting aside the medium term, shorter term the UKMO fax chart still shows some possible snow at T72hrs.

Quite unusual to see an Atlantic front surrounded by sub 528 dam, any milder air gets squeezed out and the front seems to slow.

yes mate & ECM 72 looks similar - Just awaiting the snow depth charts to update

*** Why are we seeing these charts appear - Yes, The most Easterly stratospheric winds ever measured in 40 years ... *** 

S

 

[Daniel*]

GFS 12Z in motion looks so clean and effortless: 

 

[Man With Beard]

The evidence grows for me. A High focused near Scandinavia for 20-25 Feb is clearly the head horse. 

Also worth noting that the lack of a deep trough over Europe is probably a good thing for cold too. Without it, the weather will probably be sourced from Russia rather than the risk of east Mediterranean air getting into the mix.

[Rayth]

My goodness ! I nearly choked on my smoked haddock when I seen @Tamara ‘Ramping’ a GFS run ?, are the stars aligning ? Are we on the cusp ? Will Tamara’s head be right all along ! Tune in next time on ... The Northen Hemisphere’s got *potential* impending talent !!! 

[karlos1983]

1 minute ago, Man With Beard said:

The evidence grows for me. A High focused near Scandinavia for 20-25 Feb is clearly the head horse. 

Also worth noting that the lack of a deep trough over Europe is probably a good thing for cold too. Without it, the weather will probably be sourced from Russia rather than the risk of east Mediterranean air getting into the mix.

Yup and with the lack of low heights across the pole, unlikely to sink! I’m beginning to get just a smidge of confidence. This could be an epic week of model watching! 

[chionomaniac]

5 minutes ago, Steve Murr said:

yes mate & ECM 72 looks similar - Just awaiting the snow depth charts to update

*** Why are we seeing these charts appear - Yes, The most Easterly stratospheric winds ever measured in 40 years ... *** 

S

 

It's not just the record strength of these easterlies but also the dynamics of how it occurred including the previous displacement, the internal trop based split and the positioning of the residual daughter vortex. Once you could see that falling into place it is no surprise to see those easterly trades.

[SMU]

1 minute ago, chionomaniac said:

It's not just the record strength of these easterlies but also the dynamics of how it occurred including the previous displacement, the internal trop based split and the positioning of the residual daughter vortex. Once you could see that falling into place it is no surprise to see those easterly trades.

Yep all good news for us...

x

[SMU]

Its a no from the ECM ...

LOL !  ECM this year becoming renamed as the most progressive model...

[Weathizard]

ECM having none of it... worrying

[SLEETY]

Ecm not in line again,always one model goes against the others

[Weathizard]

Blimey... ECM is in real party pooper mode, looking comparatively awful at 192, very disappointing that the top verifying model isn't on board

[ICE COLD]

4 minutes ago, Weathizard said:

Blimey... ECM is in real party pooper mode, looking comparatively awful at 192, very disappointing that the top verifying model isn't on board

The top verifying model on a global scale . So that can't be counted for are little area Of the globe ?. Not saying it's wrong , just saying .

Edited February 10, 2018 by ICE COLD

[shaky]

One of the models is gona be extremely wrong here and boy i must say ecm is starting to concern me!!if its the same tomorrow then it could be onto something!!

[Stuie]

8 minutes ago, Weathizard said:

Blimey... ECM is in real party pooper mode, looking comparatively awful at 192, very disappointing that the top verifying model isn't on board

Sorry mods for a one liner but, top verifying model? Is it? All I seem to see from the ECM is failed output post 5 days.

EDIT: In fact maybe it is better for the ECM to look like it`s not playing the game as I haven`t quite got over when it failed `that` chart years ago.

Edited February 10, 2018 by Stuie W

[nick sussex]

Yuk! 

The ECM really not interested but it’s better upstream at day 8 than this mornings run.

[SLEETY]

It’s been pretty awful this winter the ecm but most probably correct this time,Norma ply the less cold solution wins out in uk

[Roadrunner]

It would be good to get the experts measured opinion on here re the ECM before @nicksussex gets inundated with orders for prozac! 

[johnholmes]

32 minutes ago, Man With Beard said:

The evidence grows for me. A High focused near Scandinavia for 20-25 Feb is clearly the head horse. 

Also worth noting that the lack of a deep trough over Europe is probably a good thing for cold too. Without it, the weather will probably be sourced from Russia rather than the risk of east Mediterranean air getting into the mix.

That last bit is so true and is often not considered on here in the general desire to have an easterly.

[Tracy Flick]

EC, JMA, GFS

Maybe the JMA has the right idea here, as it's roughly the halfway house.

The EC gives a sudden spring warming.  The sudden stratospheric warming had may as well not even be happening as far as the EC is concerned.