comet
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If the outcome in 7 plus days time is anything like what we are seeing tonight on the pub run remember the lowly GFS 18z delivered it to us first.
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I said a few days ago that the models could be making a meal out of the troublesome lows in the Atlantic that are hindering height rises north this could still be the case. By Sunday we should definitely know one way or the other what sort of weather we can expect the weekend after next.
The EPs, Met etc will be no benefit either. I'm afraid they to have been just as fallible.
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36 minutes ago, chionomaniac said:
Cough... This statement couldn't be more untrue, lol. SSW late Dec 86 leading to this:
I have seen this before but there is no trace of it in the lower strat when you look on the ESRL daily mean composites charts above 100mb. Just realised I should of been looking at the anomaly charts rather than the mean. Good to see that the records back each other up. I had been dubious of the ESRL charts for a while now because of this. Cheers.
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Seems to me that Mr Cohen does not have a Scooby do about what may happen or may not happen. So much for a -QBO = weak vortex, this may be due though to the fact that it has been allowed to build unaffected in the mid to upper strat because of the disconnect and little if any wave breaking in the upper strat.
I think I am correct in saying that the infamous cold spell of Jan 87 was the result of a decoupled trop and strap with little in if any signature of raised heights or warming above 50 or even 100mb.
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Quite positive output tonight from a coldies perspective. I do wonder though if the models are over milking these spoiler lows but if they do manage to scupper a significant cold spell with a very conducive AO and NAO then it really will be a great chance missed. I can only assume these mid Atlantic spin off lows are a result of the Atlantic sst profile. As I said before though fingers crossed the models are making a meal out of them.
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The Ukmo charts again look positive. The 0z t120 chart almost identical to the 12z 144 chart yesterday when i said the high closest to the UK would slide away southeast with delayed Atlantic heights then building. This can clearly be seen on the 0z t144 chart this morning with post t144 looking very promising. Nothing to get hung up about I would expect a good afternoon and evening model watching to come.
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Good runs tonight. lets just hope they now build on this and not backtrack into another pickle again tomorrow.
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Good model output so far tonight even the UKMO run is not to shabby although a slight delay in Atlantic height rises until the high just to the west of the UK slides away southeast. Definitely get the feeling that there could be colder upgrades on the way. Lets hope the ECM run keeps up the positivity tonight.
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1 hour ago, northwestsnow said:
The pick of the big 3 at 144 is UKMO in my opinion.
Surely the only way forward from there is retrogression?
That said, and in the interests of balance im not sure how much stock im placing in UKMO at the moment, seems to be having wobbles.
Yes I would take the ukmo t144 chart over the other two without question. There seems little point looking beyond this time frame until the models can reach agreement.
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Take what the Met say with a pinch of salt, that would be my advice. Mind you If they happen to be right then a pinch of salt for winter 17/18 would probably be about right.
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23 hours ago, Yarmy said:
The last adjusted reading was 66.1. 67.4 was the last observed flux, but you have to homogenise the numbers to account for the Earth's varying distance from the Sun during the year. This is the lowest solar flux value since the previous solar minimum.
You are quite right. If memory servs the lowest actual figure we can obtain is 69.5
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30 minutes ago, blizzard81 said:
So in a nutshell, coldies make the most of the possible end of November cold spell?
I would not worry yourself to much, we had plenty of this in depth analysis during the summer, last winter etc, etc which at times was less than accurate shall we say. There are no experts on this or any other forum that know what lies ahead during the coming months.
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Wave 2 geopotential height rises in FI now showing on gfs instant weather maps. Got to be one of the longest sausage shaped vortices at t300 70mb before heading towards a split at end of run at 50,70 and 30mb.
Now that has got my attention.
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8 hours ago, Snowy L said:
I remember Chiono explaining to me about what happened in 2010 as there was nothing in the stratosphere happening that could have indicated the tropospheric vortex being completely destroyed twice in November and December of that year.
Basically it was wave breaking in the troposphere, so a troposphere-led split of the tropospheric vortex.
BTW I am not suggesting we will get 2010-like conditions, just thought this is a useful example of how we can still get brilliant tropospheric synoptics without the help of the stratosphere.
There was warming in the strat prior to the cold spells of 09/10 and Dec 10. Also more importantly we had increased geopotential heights up to 30mb and above None of which is being shown in the strat forecasts.
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Mr Cohen's theory has bombed the last few years, plus his weekly updates appear nothing more than guess work which do him no credit.
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Just now, oasis said:
I saw mentioned about lack of stratopsheric tropospheric coupling in near future, suppose if these charts can happen, that would mean upper vortex not filtering down?
by the looks of things the strong northern blocking being shown by the models in the mid to long range is completely trop led, with a total disconnect between trop and strat.
I have always been of the belief that such blocking would have to be coupled to the strat at least up to 30mb level or higher so I for one am very surprised to see such blocking in the charts. Mind you it has not verified yet
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On 02/11/2017 at 20:40, Blessed Weather said:
With regard the exact impact of a warm Arctic we appear to be witnessing a huge experiment playing out in front of us at the moment. But of interest to our little island, the scientific community do seem to agree that the reduced temperature gradient between the Arctic and the mid-latitudes will reduce the 'fuel' that drives the jet stream and increase the frequency of a meandering (meridional) jet and 'stuck' weather patterns. Here's a couple of snippets from a well written article by the Guardian newspaper in Dec 2016. Well worth a read.
It’s safe to say [the hot Arctic] is going to have a big impact, but it’s hard to say exactly how big right now. But we are going to have a lot of very interesting weather – we’re not going to get around that one.
The clearest connection so far between the melting Arctic and weather is for extreme winter conditions, such as the intense winters that hit parts of North America and northern Europe in 2009-10, 2010-11 and 2013-14, causing record snowfalls and billions of dollars of damage. In those years, the jet stream deviated deeply southwards over those regions, pulling down savagely cold air. Prof Adam Scaife, a climate modelling expert at the UK’s Met Office, said the evidence for a link to shrinking Arctic ice was now good: “The consensus points towards that being a real effect.
Getting back on topic, the October snow cover index has ended up above long-term average, so as Judah Cohen says "let the games begin"!!
Learn't to take what Mr Cohen says with a large dose of salt and that goes for his theory as well.
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3 hours ago, reef said:
Living somewhere that always benefited from northerlies it has definitely been a major issue in recent years. The polar air is slightly warmer, travelling over a longer sea track due to a retreated ice edge and being modified by SSTs much warmer than normal on its way here. Its a triple whammy, assuming the jet relents long enough to allow a northerly in the first place!
I had replied to your post and will try to do so again. As vizzy 2004 has also said, in the last several years we have not seen a long fetch northerly from well inside the Arctic circle for comparison purposes. let's hope this winter will change that.
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Nice post from Mr Murr, although Imho I think perhaps he is overstating the polar warming and the effects this would have on latitudes further south. Give or take a degree a long fetch northerly would I think still produce similar to what it did 30, 40 50 years ago and the same would apply to East/ north easterlies.
We are though most certainly no closer to accurate long range forecasting.
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1 hour ago, booferking said:
It's not snow were looking for it just your normal Autumn feel frosty crispy weather while snow fields build just to the east of us.
That will do me at this early stage.
It will be a welcome change if it comes off with a much more seasonal feel to the weather and yes although no one is realistically looking for snow at this stage we know it isn't outside the realms of possibility either.
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20 hours ago, KyleHenry said:
Question. Where do you surmise energy eminates from to allow temp rises in the Stratosphere and in those rare occasions what source/ sources of energy/geophysical conditions combine to produce a SSW?
If I'm looking for say an EAMT event. I look to MJO sector 3, and a significant break out from the COD region.
Tropospheric HP needs to be aligned in the correct geographical position. This I believe this acts as a springboard towards access to the lower Stratosphere.
The PV needs to be in the correct angular momentum at the exact time of this event to accept the energy transfer and allow wave 1 or 2 to progress into a SSW.
Otherwise the wave is restricted in its strength to break through.
I am also aware of the PV undulating in heights during rotation and convection phase of the Northern hemispheric winter period. To which this also adds an extra energy source for temp rises at the Strat level.
Energic particles from solar radiation of the ionosphere down to the mesosphere and possibly lower, is another theory that I need more study of, regarding knowledge of all sources from which energy transfers into Strat.
There is clearly a multilayered process, therefore there is a multilayered answer. But there is an answer.
The MJO, I believe a major key component in finding such an answer to forecast specific events in conjunction with above mentioned phases.
While I agree the MJO can sometimes given the right conditions aid in heat transfer to the strat it is not the be all and end all, far from it. Plus although heat transfer is of course important what is even more important is geopotential heights .
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I would not be jumping the gun with regard to the MJO affecting the strat etc . correlation does not mean causation. We have seen strong MJO events in the past with little effect in the strat. In fact it could be strat influencing the MJO. Also the QBO definitely in the easterly phase.
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Way to early still to get a feel for how the upcoming winter will pan out. However at this point in time I feel more confident of seeing a significant cold spell for the UK with laying snow and negative max daytime temps even if it only lasts for a week or so. Compared to the last few winters this would be notable and welcome event should it happen.
I am probably hedging my bets on what we are seeing in the strat in the forecasted period and the propensity for northern blocking that we are seeing in the model output, with the likelihood (hope) of this being being repeated during the coming winter months.
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19 hours ago, Daniel* said:
Interest builds.
The gfs has been showing this for a few days now. It would of course be a lot more interesting 5-6 weeks from now.
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Model Output Discussion 01/09/17
in Forecast Model Discussion
Posted
I still would not discount a cold/ very cold spell establishing itself in 6 to 10 days time. Still plenty to play for.
The Jarma charts for what they are worth are good.