I actually believe we have an SSW underway right now, and the confusion in the models is reflecting this.
Originally Posted by: Sevendust
The warming that occurred post Christmas + general stratospheric warm up since is probably the reason things have slowed somewhat and we can see some cold in the models.
Originally Posted by: johnm1976
Be interesting if that could be proved
Meanwhile, the 6z shows a messy picture. The UK under trough based slackness which eventually allows an easterly in FI
Much as the MetoFaxes indicate, a low looks set to slide under the Scandibloc but the uppers aren't that great
Plenty more rain for some in the next few days
Originally Posted by: warrenb
Well, correlation is never total proof of cause, just a probabilistic balance.
I've been watching the strat for several winters now, on a purely subjective observational level.
It is my perception that even small changes in strat temperature produce tropospheric results, sometimes subtle or short lived.
An example would be a slight shift in stratosphere temp from below to substantially above average in late November/ early Dec 2012. It really was a blink and you'll miss it kind of event, however....
This preceded a great deal of excitement on these forums and a week or so later we had transient, localised ice days and some lying snow.
As the warming was relatively minor and transient, however, I did not expect the cold to last and sure enough it was not until a much bigger warming the following January that we got a lasting snow event which was followed by incursions all the way into Spring 2013.
On the flip side the major SSW of late January 2012 delivered sustained deep February cold to continental Europe, but the same plunge merely kissed our East Coast, so it is far from exact.
There are people with far more knowledge than me and better brains who could probably make more of this.
For interested model watching coldies who are condsidering a jump off the Humber Bridge in an endless zonal winter, however, I would say the strat is always, always worth a look before you go! You can go all the way out to t+384 on GFS at both 10 and 30 hPa and it's accurate out to about t+192, and still better than tropospheric modelling at t+240.
The only bad thing is that it is difficult for those without a great deal of time to access ensemble data. You can get raw data from NCEP or pay to see it on a specialist site.
I would say if the tropospheric ensembles and the control runs don't deliver but the strat has been warm, then have your snow shovels and sledges ready and expect a flip..... that's how strong I think the correlation is from having followed it for a while.