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Paul

Cold hunt - models and chat

Paul

Please ensure that the majority of your posts in this thread are model related - a theme of model discussion needs to run throughout.
Some off topic chat and reactions are ok, but please use other, more relevant threads for entirely off-topic chat (such as snow reports, met office forecasts and general chat/moans about the weather or this winter).

For more no banter and just model discussion please head to the new focused model thread - this is also a great place to post (or cross post) your longer model summaries or thoughts around the models.

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Tick tock goes the clock, not over yet...is it??

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21 minutes ago, edinburgh_1992 said:

I agree, i think I'm going to give the models a rest for a while as the output is just depressing at the moment. Just as I start thinking to myself "-4 uppers, could be worse, at least it'll feel wintry", the models hit me back with raging southwesterlies. Hopefully by next weekend we should start seeing some clearer signals in the right direction. 

Been hearing that all winter. We may have to face facts that this winter will go against all the signals. Yes there is still time but the chances of getting another beast at the end of Feb for the second year running is remote.

What would be interesting is if Feb turned our to be the complete opposite of what the signals suggested. I for one would never believe them again.

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2 minutes ago, Djdazzle said:

Been hearing that all winter. We may have to face facts that this winter will go against all the signals. Yes there is still time but the chances of getting another beast at the end of Feb for the second year running is remote.

What would be interesting is if Feb turned our to be the complete opposite of what the signals suggested. I for one would never believe them again.

Good point, but perhaps no more remote than the fact we had 2 large scale SSW events I side a year! 

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1 hour ago, Catacol said:

I’m not convinced about early spring - while we have failed to get a reversed pattern we have seen cold air spill out of the arctic, and the jet overall has dropped further south. I don’t see a warm March - anticyclonic and grey would be my call given ongoing expectations that the Atlantic will gradually fade under SSW conditions.

Totally agree about North Atlantic rolling over the top. The odd thing is that it hasn’t actually been stormy. If we think back over the last few weeks we have had very little in the way of strong cyclonic activity.....and yet still we haven’t managed to get a block to pop into place. It’s as though the 2 sumo wrestlers in an earlier analogy have actually found themselves both to have a pulled hamstring!

But that doesn’t make sense when one considers the momentum profiles over the winter so far and the easterly bias that has definitely landed now on zonal wind profiles. We have Masiello posting GFS flow diagrammes showing a big Siberian high building as this easterly momentum gathers influence, but the North Atlantic remains blissfully in a +NAO state. I like to try and see through the language of expert posters....and I thought Amy Butler’s tweet earlier was interesting- advertising a tanking AO heading to around 2 or 3 SDs below 0 and then adding in passing that the NAO however was set to remain positive. No explanation of that fact - just a statement. Also therefore puzzled? And Dean from the Met on twitter posted that the SSW was so severe in its impacts on the trop that it was blocking the MJO signal. I’m lost on that one - it’s an interesting view and probably reveals my lack of understanding....but conceptually I don’t understand what he means by that, and it feels a bit contentious.

Best argument out there to me has been the idea that the atmosphere has actually been very unstable and twitching in response to the interplay between a very warm polar stratosphere coupled with a very cold tropical stratosphere. Suggestion here is that, under very cold tropical strat conditions, the MJO loses its coherence and jumps around a lot....and that the speed of transfer between phases without any sustained holding in either 7, 8 or 1 has prevented the block from forming. We certainly have had some very swift MJO progression so maybe there is something in this explanation...and a twitchy atmosphere would create tropospheric vibration too insignificant to shift the whole pattern. Maybe.

I did also read earlier today the article linked by Butler to QBO research. Authors acknowledge a definite connection between QBO sign at 15 and 30hpa and NAO and AO tendency. We have been wQBO at those heights for a while, so there is a forcing we can grasp. I think we all knew going in to this winter that it was disappointing that the eQBO was on its way out, and back in early autumn some of us were posting hoping it would slow its progress. This fact we have been ignoring over the last month.

Anyway enough waffle - I am looking forward to seeing whether late winter brings any interesting variations. We should all know by now that the long range Met forecast isn’t worth toast and jam.... and twice in six years March has delivered more cold and snow than any of those same 6 Februarys.....so maybe we are seeing a pattern developing regarding the back end of winter in the current period. Cold and anticyclonic March wouldn’t need too many tweaks to become blocked and easterly.

And this EPS chart isn’t far off being interesting. Winter isn’t over yet....

91E8D10D-38FE-4C4D-B239-CB76CDB2322A.thumb.png.dbb2548c2590a45b7f9547e81b968dc9.png

 

My take on the winter as a whole .....if you did ignore the science, background signals, favourable this and favourable that, and just looked out the window 99 % of UK folk have so far  experienced nothing short of standard fare winter weather. I don’t think anyone denies these signals have a correlation to wintery weather....but pinning a certain signal to a certain outcome is, for this moment in time,  a little Russian roulette with Lady Luck 

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After taking a break from the models the last few days, I think I will continue to take a break and enjoy the snow I currently have.....

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7 minutes ago, Don said:

After taking a break from the models the last few days, I think I will continue to take a break and enjoy the snow I currently have.....

Nice on. See you in October. 

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Just now, mountain shadow said:

Nice on. See you in October. 

More like Sunday evening as this cold spell ends!  ?

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3 hours ago, Catacol said:

But that doesn’t make sense when one considers the momentum profiles over the winter so far and the easterly bias that has definitely landed now on zonal wind profiles. We have Masiello posting GFS flow diagrammes showing a big Siberian high building as this easterly momentum gathers influence, but the North Atlantic remains blissfully in a +NAO state. I like to try and see through the language of expert posters....and I thought Amy Butler’s tweet earlier was interesting- advertising a tanking AO heading to around 2 or 3 SDs below 0 and then adding in passing that the NAO however was set to remain positive. No explanation of that fact - just a statement. Also therefore puzzled? And Dean from the Met on twitter posted that the SSW was so severe in its impacts on the trop that it was blocking the MJO signal. I’m lost on that one - it’s an interesting view and probably reveals my lack of understanding....but conceptually I don’t understand what he means by that, and it feels a bit contentious.

 

Its certainly all very interesting!

I seem to keep on remembering though when the vortex shattered it split into many splinter pieces, there were like 3-4 different lobes, and indeed even now if you look there are various lobes splinting off, like the snow system we've literally just had. IMO these little lobes right at the start of the event prevented any northern blocking and actually kept the pattern quite flat (the squeeze job in the failed easterly is a perfect demonstration of that in effect, the space just wasn't there for any subtropical ridging to punch through the ring of PV lobes that were littered everywhere.) I think had we had a cleaner split from a less severe SSW then there would have been that breathing room for northern blocking to blossom and then it would in itself start to modify the distribution of the key features, I'm thinking like the 09-10 type winter.

However because it didn't take hold early enough one PV lobe latched it itself into place over Ne Canada, a favoured spot, and has basically spun away unfetered. And with no ability to have another SSW and a messed up tropical signal, we've had no real way of dislodging it from its spot. Now we are finally getting a response from the troposphere but the pattern is very locked in place now. Probably won' shift much until any final warming IMO, unless the Siberian high grows so strong it starts to disrupt the pattern again, but that feels a long shot right now.

I do also agree regarding the QBO. Once again I remember some statistics that in this mode of the QBO, only 2 out of 13 SSWs have had any major impact on the troposphere. That's very poor average, and one of those was 2013 which took the best part of two months! So this maybe the 3rd out of 14 to have some major impact, even if it isn't benefitting us.

Also, I do vaguely remember reading what someone on Americanwx said that a lot of the indicies at the moment seem to be loaded to extreme ends one way or the other, they aren't often middling in the last few years. I suppose US PV outbreak and our summer are examples of the results when an extreme pattern can set-up.

Edited by kold weather
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Looking forward towards end of Feb and March, that's when proper cold and dry snowfalls seem to happen now so back in a couple of weeks when the models should be picking up the signals ⛄❄️⛸️?

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5 hours ago, Don said:

After taking a break from the models the last few days, I think I will continue to take a break and enjoy the snow I currently have.....

At least you got some snow! It’s delivered pretty much nothing in Essex.

I am now almost longing for the warmth of the sun on my face.

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Regarding the hunt for cold, with the countless charts from various models I have reviewed this morning I think it's fair to say, by far the best by a country mile for cold and snow potential are the ones at T+0 !!

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My God, has anyone seen this mornings GFS?

It is seriously bad and brings us a mega Bartlett and blow torch conditions from 7 days out, you could ignore the run except it mirrors yesterdays ECM.

February is looking more like 1998 to me than 2018!

Oh dear................

Andy

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You thought yesterday's ECM was bad then close your eyes today

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But the back ground signals all say different.  Oh wait they have been saying that since December. 

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7 minutes ago, minus 9 said:

But the back ground signals all say different.  Oh wait they have been saying that since December. 

Short term modelling has improved greatly over the years but it’s fair to say that long range forecasting hasn’t. The weather still retains the ability to make fools of us.

The big problem with long range / background signals / teleconnections etc is that they all come with so many caveats.

All we need now is a summer dominated by northern blocking! ??

 

Edited by Djdazzle
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33 minutes ago, Penrith Snow said:

My God, has anyone seen this mornings GFS?

It is seriously bad and brings us a mega Bartlett and blow torch conditions from 7 days out, you could ignore the run except it mirrors yesterdays ECM.

February is looking more like 1998 to me than 2018!

Oh dear................

Andy

The op being on the mild side of the ensembles with attempted ridges both of the high towards and over the UK.

i suggest you look up what a Bartlet high is maybe you can show me one for example that has a low over Europe?

C2523986-A6D0-40CB-AE51-1AF608F6212C.thumb.png.ad1fc8c00102d68fb345c8c1022c5e53.png

 

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Surely the likes of Tight Isobar and all those who solicited false hope re the long range teleconnections/ssw effects etc etc must be tucked away in a corner somewhere eating humble pie right now having seen some of the latest stomach churning FI charts..:help: Perhaps time to admit defeat eh ? I’d challenge anyone to put a positive spin on this chart.

E0FFF0C4-A038-484E-B561-4957BD4899F9.jpeg

Edited by Newberryone
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1 minute ago, Newberryone said:

Surely the likes of Tight Isobar and all those who solicited false hope re the long range teleconnections/ssw effects etc etc must be tucked away in a corner somewhere eating humble pie right now having seen the latest stomach churning FI charts..:help: Perhaps time to admit defeat eh ?

E0FFF0C4-A038-484E-B561-4957BD4899F9.jpeg

Is that chart at day 10 going to verify

i think you can only feel let down if you are a child 

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7 minutes ago, Newberryone said:

Surely the likes of Tight Isobar and all those who solicited false hope re the long range teleconnections/ssw effects etc etc must be tucked away in a corner somewhere eating humble pie right now having seen the latest stomach churning FI charts..:help: Perhaps time to admit defeat eh ?

E0FFF0C4-A038-484E-B561-4957BD4899F9.jpeg

Time to admit defeat over a +10 day chart? F f s! 

Edited by Stevie B
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1 minute ago, knocker said:

It is not fair to say long range forecasting hasn't improved. Some people just expect too much.

But this one looks like being completely wrong! Maybe I should clarify my previous post to say that they still have a long way to go in terms of reliability.

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I would be a liar if I said the GEFS 00z mean was anything other than abysmal for further cold prospects out to mid Feb and beyond..there's lots of mild in there.

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7 minutes ago, Newberryone said:

Surely the likes of Tight Isobar and all those who solicited false hope re the long range teleconnections/ssw effects etc etc must be tucked away in a corner somewhere eating humble pie right now having seen the latest stomach churning FI charts.. Perhaps time to admit defeat eh ?

E0FFF0C4-A038-484E-B561-4957BD4899F9.jpeg

I like reading posts by people such as Tight Isobar, Steve Murr etc. But too many people (especially newbies) read them and believe it’s a dead cert. Then other less experienced posters ramp it up.

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8 hours ago, Quicksilver1989 said:

I think sometimes an SSW may work against us? If we get a split vortex then the lobes may fall into the wrong place? If one happens to fall into NE Canada than that may well just power up the jet. The temperature anomaly patterns certainly suggest that there has been an increase in cold air spilling from the arctic into mid-high latitudes

image.thumb.png.538eae18fcc8c1a5043a78df4bd78d21.png

Perhaps we were just in the wrong place?

Last two weeks certainly shows a typical ssw response but as is often the case, the uk is at the end of the line and with a strong Canadian vortex in place, the conditions we have had would i guess, be expected as we sit in the battleground 

14D956BE-182E-4EAC-A67A-2452883AED31.thumb.jpeg.9693c844bf8f61f67b0565f495e1a8f5.jpeg

8 hours ago, Catacol said:

 

I did also read earlier today the article linked by Butler to QBO research. Authors acknowledge a definite connection between QBO sign at 15 and 30hpa and NAO and AO tendency. We have been wQBO at those heights for a while, so there is a forcing we can grasp. I think we all knew going in to this winter that it was disappointing that the eQBO was on its way out, and back in early autumn some of us were posting hoping it would slow its progress. This fact we have been ignoring over the last month.

 

 

Still not sure why weatherbell nao charts are different to others ......that shows a fairly neutral resultant nao but certainly not a positive one over the past couple weeks 

8E0EE97A-250E-4C6B-9ECF-6145832FD337.thumb.jpeg.c3e5ed8fdeb7167b0d407d3550ddbfa4.jpeg

 

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