I keep an eye on the ECM strat forecasts here:
http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html
There's been a developing signal these last few days for significant disruption right at the top, a displacement event caused by a plume of warm air being pushed over the Pole. It's also worth mentioning that at the lower levels the vortex is struggling to ramp up significantly... the zonal speeds at 30hPa aren't forecast to increase much, if at all, over the next 10 days. You would normally expect a gradual increase as the polar night sets in.
Also, back to the more normal models, the 6z GEFS has taken a marked turn torwards the colder cluster in the mid-term, with the 850 mean dropping a couple of degrees from the 4th (compared to the 0z run).
EDIT: The 0z EPS means are around half a degree colder in the same period compared to last night's 12z run, plus the 0z op ECM was warmer than the entire pack by day 10 down here.
Let's see if this trend towards colder outputs continues this evening.
Originally Posted by: Retron