Model Output Discussion - 05/01/2016 18z onwards

[Nouska]

20 minutes ago, feb1991blizzard said:

Well not an SSW, it would take a lot more after that but it isn't as good as I thought tbh.

 

It looked about 5 or 6 frames before the end to be far ahead of previous runs, I expected to see red near to the North pole, still very decent though but probably not worthy of my original post, more runs needed.

The 12Z parallel also flirting with this.

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=204&code=0&mode=10&runpara=1&carte=1#

[Geordiesnow]

I see the models are trying to make the best out of what we got, just think it could of been so much better even without the proper Greenland high if the trough that is over us now cleared as quickly as the Euro models first forecast, therefore if things did get messy and slack like they are going to be it seems, then at least we could be more confident about things being on the right side of marginal. 

It certainly going to be a forecaster's nightmare next week, one thing that might favour snowfall is that there shouldn't be too much wind so evaporative cooling could well take affect. Hopefully the cold can be extended as much as it can but it be foolish to read too much into the outputs beyond the medium timeframe at this moment in time. 

Despite what some say on here, the GFS has been spotting trends lately and proving to be right if albeit some of the details on each run does leave something to be desired but take away from that, never discount what the GFS says at times. 

[Hotspur62]

2 minutes ago, Earnest Easterly* said:

To add some contrast in here not to be taken seriously It really does turn very ugly, as blocking wanes and dissolves, with PV wanting to reconsolidate into a scary sight, giving way to very mild conditions, with long fetch SW'lies from Azores with the return of the fat Euro Slug, RIP the rest of January, although Knocker wouldn't mind he might pop out his woodshed. A lot of water to go under the bridge, oh I do hate cliches. 

I know it is only just one run and shouldn't be taken seriousily ut that takes us almost back to square one and the mild December we have just endured.

It really has been an amazing 5 days with some quite incredible charts on Tuesday a la December 2010,then a backtrack to less cold conditions and today models have swung more in favour of quite a decent cold spell for some with elevation playing a key part in terms of snowfall. If we can get the cold in and it lasts till this time next week or even longer I am still holding on to GPs comments and Tamara"s comments and hope that their thoughts come to fruition going into the final third of January. Interesting times compared to last 2 winters ...   

 

[Captain Shortwave]

That's yesterdays day 5 chart Carinthian (not sure why it hasn't updated on meteociel but it has on here)

The front clearing the south east will likely have some back edge snow on it, actually a rain to snow event looks most likely in my view with cold air digging in behind that front with the 528 dam line well south of the UK by then.

This coming week shows a lot of disturbances and with conditions turning increasingly cold, so does the chances of snow at low levels.

Edited January 9, 2016 by Captain Shortwave

[feb1991blizzard]

Just now, Nouska said:

The 12Z parallel also flirting with this.

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=204&code=0&mode=10&runpara=1&carte=1#

Good spot, I haven't been following the parallel as religiously as I used to, has the parallel got any early signs of good verification?, probably one for Recretos to answer really

[northwestsnow]

2 minutes ago, Captain Shortwave said:

That's yesterdays day 5 chart Carinthian (not sure why it hasn't updated on meteociel but it has on here)

 

Looks good to me

[nick sussex]

Its funny although the easterly drama of last week went pearshaped the cold that left to the ne has resulted in some unusually cold 850's showing up on the UKMO charts for the actual synoptics on show.

Roughly -8 Midlands to around -10 towards Scotland at T120hrs.

[feb1991blizzard]

10 minutes ago, nick sussex said:

Its funny although the easterly drama of last week went pearshaped the cold that left to the ne has resulted in some unusually cold 850's showing up on the UKMO charts for the actual synoptics on show.

Roughly -8 Midlands to around -10 towards Scotland at T120hrs.

Surely that's guaranteed snow territory in terms of PPN type?

Edited January 9, 2016 by feb1991blizzard

[northwestsnow]

1 minute ago, feb1991blizzard said:

Surely that's guaranteed snow territory in terms of PPN snow?

You are similar to me height wise around 200m - should be good enough i would have thought

asit stands 

Edited January 9, 2016 by northwestsnow

[feb1991blizzard]

4 minutes ago, northwestsnow said:

You are similar to me height wise around 200m - should be good enough i would have thought

asit stands

I get the feeling though that there just isn't going to be enough PPN around, lower 500mb temps thus steeper lapse rates in between fronts would be great giving higher cloud tops.

Polar low definitely off the menu now.

Edited January 9, 2016 by feb1991blizzard

[northwestsnow]

Just now, feb1991blizzard said:

I get the feeling though that there just isn't going to be enough PPN around, lower 500mb temps thus steeper lapse rates in between fronts would be great giving higher cloud tops.

You could be right, but there appears to be a fairly sturdy trough pushing SE - im guessing the irish sea will aid precipitation intensity as the system moves in.

All conjecture at this range might push through NI/Wales yet, i wouldnt be suprised.

[nick sussex]

2 minutes ago, feb1991blizzard said:

Surely that's guaranteed snow territory in terms of PPN snow?

That's just off the raw output and using that 850 guide. I think inland away from coastal regions with that onshore flow will help and of course your altitude certainly helps. Unfortunately the UKMO keep too much data under lock and key as if protecting the Crown Jewels!

[Mark Neal.]

Yes Nick just been doing the Meteociel upper air temp look on UKMO charts using the Pressure, Dam Line table. 

Edited January 9, 2016 by Mark N

[nick sussex]

Just now, Mark N said:

Yes Nick just been doing the Meteociel upper air temp look on UKMO charts using the Pressure, Damn Line table.

Yes that's the guide, its certainly a help but it would be even better if the UKMO would just be less stingy with their data. Be careful apparently the UKMO Data Protection Unit will be after us for having the cheek to try and decipher their cryptic outputs! lol

[Tamara]

1 hour ago, karlos1983 said:

Well I'm glad Ali put it out there as I was thinking the same I must admit after your post. Last thing we want is a positive AO And NAO, although you didn't state that exactly, that's where my head was. 

I'm considering a cheeky PM to Stewart or Tamara. I'm in need of some urgent torpedoe reassurance 

Well I will try my own continued thoughts from recently anyway. Stewart would I'm sure be able to give you a more technical insight answer

Trust in the upstream loaded amplification pattern was a main mantra of the last post. The last couple of days have been well worth sitting out I think whilst intra day modelling has ground on with solving the minutia placement details of this upstream pattern shaking hands with an end of the line euro/UK trough buffer. Almost insidiously, ongoing GFS machinations aside, agreement is being reached (and it will be) on the upcoming cold spell lasting into next weekend at least.

Meanwhile, out in the bigger picture, with these fundamental changes happening across the synoptic pattern, we should also continue to trust in the insanity of the state of the atmospheric circulation to provide us with more than just a one-off cold spell this winter  - following the ridiculously above average temperature pattern in UK and NW Europe of the first half of this winter ,

Its a historic Nino atmospheric response for sure, and it cannot be emphasised how unusual this is, and hence the modelling dis-array at the same time as a tropospheric tsunami assaults a cold vortex from below and starts changing the northern hemisphere pattern which is becoming increasingly receptive to very high AAM poleward flux plumping up amplified ridges at higher latitudes in stark contrast to what we have seen so far this winter

That is of course the same link as posted by Lorenzo this evening with his good analysis on the other page - but for my purposes of reply, the supply line of those deep orange colours above the total AAM line graph (which are indicative of poleward directed Teflon coated Pacific westerly wind anomalies) is far from finished and will continue to have implications for the polar profile and our upstream jet implications in the further outlook period and indeed the rest of the winter

Simple me as I am I've not , and have not at any time this winter as most will know, used composites or analogues beyond (in the here and now) keeping Jan/Feb1983 as a mental benchmark comparison (which I'm very pleased Stewart endorses) in terms of the way the atmosphere is behaving - although 2016 eclipses it in response extremes. In truth, I am finding comparative analogues impossible anyway to find based on the uniqueness of  the ocean/atmosphere state of 2015/16

A few things though:

1) First of all there is further significant kelvin wave activity in the Pacific generating yet further westerly winds to be fluxed poleward and supplement ongoing amplification from upstream, and bolster atmospheric angular momentum.  WWB's are common right through the mature stages of Nino events but based on the unprecedented nature of this one, what is important is that its forcing influence looks set to become increasingly focussed from the Central Pacific as relative cooling continues on both eastern and western perimeters of the ENSO regions. This more centralised forcing teleconnects increasingly, the longer the winter goes on, to subsequent +AAM based poleward flux increasingly shifting the Atlantic pattern east and locking in any future amplified ridges accordingly - so that the cold cannot lift out as easily as a west based pattern - especially with cold air rapidly accumulating to the NE to quickly tap into *See 3 below*

As I posted the other day, with Feb archive charts, this type of synoptic representation occurred in Feb 83 - with the amplification ridges eastward of where the upcoming amplified pattern looks to be setting up. We maybe very slightly ahead of 1983 even in terms of latent amplification potential. Its going to be highly interesting to see exactly how the rest of Jan, and especially Feb pan out.

2) In conjunction with 1) to the amplified supply line, It looks to me that we are on an accelerated track in terms of the next tropical convective cycle back to the Pacific that raises large doubts about the current modelling interpretations post next weeks amplified cold pattern to return to a +AO/NAO. Certainly anything sustainable. I wouldn't be too taken in by the COD  ( no added interference of any kind with the base Nino state) and or new cycle Indian Ocean influences dampening GLAMM at face value

Based on what were very tentative indications of the start of the current cycle (now concluding) which I posted at that time (end of November) as indicative of future activity finally arriving in the Western Pacific by New Year and having implications as one major contributor to a mid season regime change (which we are now seeing), I am taking similar very provisional tentative ECM ensemble hints of a rapid recurve of the next MJO cycle through the COD diffuse response area and back towards Phases 5/6 as indications of how the regime change is set to kick start fast track seasonal tropical activity. Fast enough to highly impact February

Any accelerated tropical convective cycle track, in itself, tells you that a business as usual sustained +NAO is counter intuitive, and I think that the models will underestimate the latent amplification flux lagged in the atmospheric circulation, and, as the vortex continues to be assailed by WAA attacks from the Pacific conveyor,and the natural seasonal longwave pattern tightens the screw, the models will overestimate increased polar jet flow (as a result of underestimating +GLAMM or overestimating the effects of any drop in relative AAM) that in turn would suggest sinking ridges back into Europe and instead adjust jet flow back south accordingly

Wrt the extratropical GWO signal which will be a much better guide to the way the synoptic patterns unfold than just taking the tropical MJO signal in isolation - an orbit through Phase 7 is ahead, tropical activity waning (temporarily), and then, as further wave flux from the Pacific ramps up AAM yet again, a further obit return to Phase 5/6 which is favourable for any mid latitude ridge still around close the UK to morph NE into sourcing some of that cold from Scandinavia. Beyond then, further retrogression looks good to take advantage of the next round of amplification coming from upstream. Next time, less west based. We then look towards further possible MJO Pacific torpedo engagement as discussed above

3) In addition to this poleward flux bombardment, we have the increasing instability of the trop/strat profile in relation to the Kara Sea height anomalies as a result of the seasonal sea ice anomaly departure albedo feedbacks. The current erratic modelling is illustrating hints at this well enough, and this also supports heights to our NE playing a part increasingly in the extended period

In simple terms we have different tin openers in operation eating away at the vortex:

The immediate effects are appearing less remarkable in proportion to the assault that is taking place above our heads, but my little analogy here of the way the trop/strat hemispheric pattern is heading through the second half of this winter is like looking at a wide car windscreen which receives a few very potent but finely focussed blows from separate pieces of debris in the air while the car (the vortex analogy substitute) is driving very fast on the motorway. The initial reaction of the glass is to crack and split at the stress centres. But then over a period of time, the stress fissures in the glass start to gather minute fracture faults and extend over wider and wider areas.....

So, ignoring the intra noise model shenanigans, the overall song remains exactly the same as before. As previously covered. The cold upcoming period is well in focus, and, a following a pause and further re-arrangement of the deck chairs thereafter we are set up up for another assault into February and, imo, the coldest potential of the winter

 

[Timmytour]

A day of mixed emotions watching the models.....always better when the mix ends up in optimism at the end of the day, though nothing yet is suggesting that a prolonged cold spell is anything more than 50/50 at best at the moment

I won't believe we are going to enter a pattern that will endure well into February until I see GP's torpedo listed in Nick F's signature

[feb1991blizzard]

Ens mean now quite significantly starting to back up some sort of warming event at 10mb, cant help thinking though its not going to be the silver bullet (SSW), chiono would have already told us it was likely to start coming in range if that was the case, he's usually cock hot when it comes to predicting modelling of SSW's

Edited January 9, 2016 by feb1991blizzard

[Trom]

Tamara - what did you make of that strange loop the GFS threw up in phase 8 the other day if you don't mind me asking?  It certainly seems to explain why the GFS has been at odds with other models.  It's interesting to see that you think that speed of the MJO is underplayed in the early phases.  If correct it means Feb could be very interesting.

Edited January 9, 2016 by Trom

[liam300]

Looking at the latest GFS, it doesn't look good for the snow on the south coast. Marginal in terms of cold and precipitation 

[BLAST FROM THE PAST]

Quote

2016 eclipses it in response extremes. In truth, I am finding comparative analogues impossible anyway to find based on the uniqueness of  the ocean/atmosphere state of 2015/16

Maybe T because one might have to go back to Dalton or Maunder times

 

BFTP

[Man With Beard]

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=192

GFS 18Z ens - I count 8 out of 20 still on a cold northerly by T192.

Been a strange few days for the GFS - the ensembles remain in no-mans-land.

Having taken in all the output of the last few days, I'm wondering if a High Pressure centred somewhere NW of Scotland is our next destination after D7

[lorenzo]

10 mb looking v interesting ... 

[feb1991blizzard]

1 minute ago, lorenzo said:

10 mb looking v interesting ... 

Looks better although doesn't the blue blob right up in the right hand corner spoil it a little?

[Bullseye]

Some signs showing for extended period? 

 

[Mark Neal.]

Sounds even more encouraging Stratospherically speaking then   Certainly encouraging that tweet with longer range models showing good signs.