Hunt For Cold: Model Discussion - Heading Into Christmas

[Glacier Point]

Agree with timings there Nick. Warming date looks to be 31st December and split on 3/4th January. That gives 11th January as first real opportunity to gauge any impacts on the tropospheric pattern. Suspect that the continued warming forecasts are a hindrance to fast downwelling.

It's all related, but the destruction of the SPV is possibly constructively interfering with the tropics. That MJO signal for week 1-2 is well beyond what we would expect for an +ENSO pattern. 

As the atmosphere choreographs itself, an MJO in Phase 8/1 and downwelling -U wind continues to be the end destination. Expectation would however be for the MJO to weaken significantly through phase 7 but regain intensity in phases 8 / 1.

Edited December 27, 2018 by Glacier Point

[Swave Snow]

2 minutes ago, Glacier Point said:

Agree with timings there Nick. Warming date looks to be 31st December and split on 3/4th January. That gives 11th January as first real opportunity to gauge any impacts on the tropospheric pattern. Suspect that the continued warming forecasts are a hindrance to fast downwelling.

It's all related, but the destruction of the SPV is possibly constructively interfering with the tropics. That MJO signal for week 1-2 is well beyond what we would expect for an +ENSO pattern. 

As the atmosphere choreographs itself, an MJO in Phase 8/1 and downwelling -U wind continues to be the end destination.

That sounds like it could be too strong again like March this year when everything was looking amazing and then it went to west in the end 

[Methuselah]

And, at T+384, there is nothing showing that we haven't seen before. If either the SSW or the myriad other signals, that are pointing to cold, don't show their hand soon, the fallout could get very interesting indeed?

[bluearmy]

7 minutes ago, Swave Snow said:

That sounds like it could be too strong again like March this year when everything was looking amazing and then it went to west in the end 

I’d happily take a repeat of March/April 2018 but this time six weeks earlier .......

[Singularity]

This SSW isn’t a traditional split IMO... it’s a sort of Frankenstein’s Monster combo of displacements and splits that may even result in three strat vortex segments by week 2 of Jan.

So we probably only see lagged responses but of a split-like variety.

 

What’s going on in the 5-10 day range is MJO-related; a sudden amplification while the planetary waves are positioned right for a possible easterly incursion to southern UK in particular. How fast the MJO propagates is important here. GFS is finding huge amp but the propagation is a bit slow and in any case it seems to be making a hash of transmitting the amplification signal to the mid-lats. No wonder NOAA/NCEP aren’t keen on its output at the mo!

[nick sussex]

3 minutes ago, Singularity said:

This SSW isn’t a traditional split IMO... it’s a sort of Frankenstein’s Monster combo of displacements and splits that may even result in three strat vortex segments by week 2 of Jan.

So we probably only see lagged responses but of a split-like variety.

 

What’s going on in the 5-10 day range is MJO-related; a sudden amplification while the planetary waves are positioned right for a possible easterly incursion to southern UK in particular. How fast the MJO propagates is important here. GFS is finding huge amp but the propagation is a bit slow and in any case it seems to be making a hash of transmitting the amplification signal to the mid-lats. No wonder NOAA/NCEP aren’t keen on its output at the mo!

It might be the GFS is still showing the lagged effects of the flatter MJO phases . The ECM has the weaker signal but is quicker to move it to phase 6 . Perhaps the ECM has strengthened its signal today and the GFS is still hanging around !

Its a shame we no longer get to see the UKMO forecast .

 

[winterof79]

20 minutes ago, Swave Snow said:

That sounds like it could be too strong again like March this year when everything was looking amazing and then it went to west in the end 

Crud wasn't it?

[carinthian]

34 minutes ago, carinthian said:

 Out of interest , I have been informed that our resort planners have just been given advanced warning of possible severe cold to affect Central Europe by the first weekend of January with very low temperatures forecast in the mountains. I am not out there at the moment so cannot provide much further information BUT will not be based on the GFS outputs. Something is stirring , I feel.

C

Probably , similar to what is shown below with very low 850mb level temps and upper cold pool in the flow. Cannot report as to what the singular model shows but would imagine close to the ECM 10 day model.

C

[Penicuikblizzard]

Certainly going to be very cold in mainland Europe,,but I think it’s going to be one of those winter seasons where the UK is in the middle, no mans land which will result in mild dry weather as we are experiencing just now.

[Man With Beard]

ECM extended ensembles this morning have lost even the faintest cold signal. By 11th January, the Icelandic low is dominant, and the UK is generally in a long draw SWly. 

[Stonethecrows]

2 minutes ago, Penicuikblizzard said:

Certainly going to be very cold in mainland Europe,,but I think it’s going to be one of those winter seasons where the UK is in the middle, no mans land which will result in mild dry weather as we are experiencing just now.

Any reason why you think that?

[stratty]

11 minutes ago, carinthian said:

Probably , similar to what is shown below with very low 850mb level temps and upper cold pool in the flow. Cannot report as to what the singular model shows but would imagine close to the ECM 10 day model.

C

 

11 minutes ago, carinthian said:

  46 minutes ago, carinthian said:

 Out of interest , I have been informed that our resort planners have just been given advanced warning of possible severe cold to affect Central Europe by the first weekend of January with very low temperatures forecast in the mountains. I am not out there at the moment so cannot provide much further information BUT will not be based on the GFS outputs. Something is stirring , I feel.

C

..........first sign of madness, talking/quoting to yourself! 

Edited December 27, 2018 by stratty

[Weathizard]

Just been looking through the GEFS, dreadful stuff! Let’s hope the Euros have a better handling on this as there’s pretty much nothing good amongst the ensembles.

[blizzard81]

3 minutes ago, Man With Beard said:

ECM extended ensembles this morning have lost even the faintest cold signal. By 11th January, the Icelandic low is dominant, and the UK is generally in a long draw SWly. 

That is a shame and doesn't bode well for the ec46 later tonight. 

[damianslaw]

Rest of the year - more of the same, mild, often cloudy, bit of dampness in the north, chance of slight frost in any clear breaks - but generally too mild. We weren't far off a cold frosty christmas week, had high pressure nosed further north as it was looking like doing so for a moment - a week of christmas eve weather would have been very seasonal. Alas it has sunk too far south, and we are in a bit of a stalemate situation - with nothing changing just moist mild dankness - very uninspiring.

As we enter New Year, ECM and GFS to a degree show high pressure again seeking to ridge north through the UK, introducing hopefully cleaner air, and a return to frost and possible fog. At the same time, low pressure is anchoring down on the mid atlantic - and it will be a case of seeing how this feature interacts with heights. We could see another 13-15 Dec situation, where we import some cold continental air again for a time,before the atlantic breaks through.

As others have said, don't expect the models to build in the possible effects of the SSW warming just yet - and a default westerly interlude as a precursor to major pattern change caused by the SSW, heights building out from the Pole, merging with heights near the UK - might well be pattern beyond the first few days of Jan, as shown by GFS and indicated by Met Office. A shortlived westerly spell before major change to cold and possible snow.

This is a rather trying time for any cold snow lovers, but as ever patience is always key, and this year we do have very weak westerlies, and if the effects of events in the stratosphere play ball as some are suggesting for increasing snow and cold chances, then we are in a much better position for snow and cold in the not too distant future i.e. mid Jan than in many other years at this stage in the winter.

[blizzard81]

1 minute ago, Weathizard said:

Just been looking through the GEFS, dreadful stuff! Let’s hope the Euros have a better handling on this as there’s pretty much nothing good amongst the ensembles.

But even the ecm ext ens trend milder towards the end by the sounds of things. I get the feeling that anything meaningfully cold is just going to be kept putting back. The only thing good about that is that we still have decent time on our side. 

[blizzard81]

The gfs is hell bent on bringing in a strong north westerly air stream by the second week of Jan. 

[Mr Frost]

59 minutes ago, Swave Snow said:

That sounds like it could be too strong again like March this year when everything was looking amazing and then it went to west in the end 

Ah the memories - greatest snowfall I have ever seen. (Pictures attached)

What a Winter/Early Spring that was!

This month has been one of the most boring and non eventful Winter months I can ever remember.

Hopefully the Metoffice and folk in the know on here are onto something - if not I will live on the Cairngorms or Ben Nevis for the rest of the Winter. 

Have a good day everyone and Happy New Year when it comes! 

Edited December 27, 2018 by Mr Frost

[DanDorsetUK]

Clearly it's not so much a lack of data this time of year but hung over data inputters with double vision! Give them a few days to come round after the new year!

[Stonethecrows]

2 minutes ago, damianslaw said:

 

This is a rather trying time for any cold snow lovers, but as ever patience is always key, and this year we do have very weak westerlies, and if the effects of events in the stratosphere play ball as some are suggesting for increasing snow and cold chances, then we are in a much better position for snow and cold in the not too distant future i.e. mid Jan than in many other years at this stage in the winter.

Which makes you wonder why all the doom and gloom. I haven't been privy to this thread over the years like many on here have but with the background signals being much better this winter, god knows what states people have been in other years.

[Sweatyman]

16 minutes ago, Man With Beard said:

ECM extended ensembles this morning have lost even the faintest cold signal. By 11th January, the Icelandic low is dominant, and the UK is generally in a long draw SWly. 

this is just #@#&*n tedious now

[blizzard81]

2 minutes ago, Stonethecrows said:

Which makes you wonder why all the doom and gloom. I haven't been privy to this thread over the years like many on here have but with the background signals being much better this winter, god knows what states people have been in other years.

Great signals are one thing. However, getting meaningful cold to UK shores is a totally different ball game - most on here are all too painfully aware of this lol. 

[mountain shadow]

2 minutes ago, Sweatyman said:

this is just #@#&*n tedious now

We're getting to the point soon where we'll just have to accept that the cards are not going fall for us with the initial SSW later this week, however, with the PV remaining under attack we may get lucky in late January/early February. 

[DanDorsetUK]

18 minutes ago, Man With Beard said:

ECM extended ensembles this morning have lost even the faintest cold signal. By 11th January, the Icelandic low is dominant, and the UK is generally in a long draw SWly. 

The calm before the snow storm fear not! Everything is resetting to default for a nice starting position. Everyone stay calm and watch it unfold before your very eyes in next week. 

[Snowy L]

I wouldn't be too upset at the models. This always happens, charts show rubbish until the SSW happens then the trigger ridge for Northern blocking appears out of nowhere. The geopotential height charts in the stratosphere look brilliant and these charts are getting into the high res timeframe now. I have no doubt the models will start showings southerly tracking jet in the day 8-12 range over the next few days.

It should be a huge red flag that models are showing the main tropospheric vortex being right over the area where there is a massive absence of vortex in the stratosphere.

Edited December 27, 2018 by Snowy L