comet

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.

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.

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.

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.

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.

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.

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.

Good runs tonight. lets just hope they now build on this and not backtrack into another pickle again tomorrow.

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.

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.

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.

You are quite right. If memory servs the lowest actual figure we can obtain is 69.5

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.

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.

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.

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.

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

Learn't to take what Mr Cohen says with a large dose of salt and that goes for his theory as well.

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.

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.

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.

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 .

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.

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.

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.