ALL ABOARD

I appreciate what your saying but your taking a 240hr chart and saying that it will depict the weather going forward. The part in bold?? are you able to accurately predict this? The whole point of watching the charts is to make educated guesses and try to provide evidence of why you have chosen them exactly as Steve has done. If it does not come off then at least he has provided a reasoning to why. For example I have taken the ECM from the 16th and posted the 240Hr chart below Now If I had said to you at this point that we would end up with a Greenland high you'd have written it off as fools gold. But here is todays chart. Completely different as yet again the PV remains on the Siberian side where as it was previously modelled to move back. I am not saying that we aren't in for a zonal spell nor am I saying that the cold wont continue but with regards to the trough digging into Europe and the Scandy high becoming a player surely it cant be written off till the event has occurred.

Appreciate that but my point was that it didn't model it correctly then so there's a chance it may not be again.

Feb just for reference go back to December 2017/January 2018 were you were posting the same tweets from the met office stating that GOLSEA5 wasn't showing a SSW, in fact it only saw a weakening of the SPV whilst other models were more bullish. We all know what happened next

I just don't see how you can spend millions developing somthing and then release it without a long period of testing in which you iron out issues. Imagine it misses the whole thing altogether?

Indeed. But GFS slightly more amplified at 108.

Just to show people how background signals can sometimes skew a FI on a model until such an event happens. For example this chart was taken on the 19th of November GFS for the 21st And 384 hours of the same run What actually transpired. Hold onto your hats it's going to be a fascinating ride. I'll add a bit so that it's relevant as don't want it moved although one would argue I'm highlighting sufficient details as to why the models shouldn't be taken at face value until said amplification has taken place. The icon was an improvement from the 12z and although we can't see it any further I'm expecting the 18z to pick up the baton.

Indeed its strange. It will be interesting to see where we go after the cold spell (if it materializes) Backgound signals showing a return to a more typical December but as each run toddles out the low solar activity may mean that the atlantic might not have as much energy as it may think.

Enough heights collapsing over scandi to allow a scandi high??

Yes further to my post above much better.

At 144 the center of the low is further north, hopefully meaning when the WAA starts to be sucked towards Greenland it will head further North.

Could it be that the latter stages of the models are reacting to the background signals that are causing the monlthys to ramp the atlantic up, but as we move closer other background signals are causing a southerly tracking jet and higher pressure to our north? It's been the story so far this autumn and if the monthly were to be believed we shouldnt be in a position were in fact heights are building towards Greenland.

Better chart from the 18z with regards to the WAA. All academic at this range tho as that low that cause the high to collapse may be a lot shallower(or not)

Sorry Mia what exactly are we looking for? Trying to learn a little bit as I also believe that an earth 4.5 billion years old dosent have its own way of doing things regardless who's around at the time.

Choo choo. The ECM picks up the Batton and dosent dissapoint. The whole PV is on the right, wrong side of the pole (depending what camp your in) Where is the atlantic? Anyone?? 216 ECM

And so the train rolls on. Icon 120. Better heights into Greenland.

The persistence of heights in and around Greenland in the continued model output is frankly remarkable. The Atlantic is dead at a time when it should be ramping up. Also there is no appetite for the vortex to set up shop where it usually does,

Much better heights into Greenland at 150. Definitely trending the right way.

''Major SSWs occur when the winter polar stratospheric westerlies reverse to easterlies. In minor warmings, the polar temperature gradient reverses but the circulation does not, and in final warmings, the vortex breaks down and remains easterly until the following boreal autumn". Butler, Amy H.; Sjoberg, Jeremiah P.; Seidel, Dian J.; Rosenlof, Karen H. (9 February 2017).

This is my understanding also. Major =reversal Minor= no reversal but slowing

Good point Feb. Wish we had full data runs to the 50s as I'd love to do a comparison.

Just to offer a different view on the winter prospects I decided to take a look at where we were this time last year, 2017 and 2016. 2018 GFS ECM 2017 GFS ECM 2016 GFS ECM So just a quick snapshot of the last 3 years and maybe a slight tempering of my own enthusiasm. On thing they all have in common including this year is higher heights across the pole and a disorganised vortex. As they say the rest is history.

Thanks for the clarity. Just seems a strange pattern high pressure trapped between lower pressure to the north and the south. I haven't seen any evidence yet of the PV wanting to locate to its usual place and the longer this goes on were bound to have the winning lottery ticket at some point.

Yes BA. Heading into December January with that profile I'd imagine a few snowblowers would be missing from the shelves. Would this pattern not present itself as a positive NAO signature on a monthly forecast?

What a strange strange chart for this time of year. Scrap that. Anytime of year

If and it's a big if the picture plays out like the 18z than can we call it a first win for old ensembles over new FV3. Maybe a downgrade more than an upgrade?