You know, a month as cold as December 2010 isn't quite so unusual if it's January or February
Let's try not to drift off topic here please - the models are showing some interesting longer-term prospects at the moment, so let's discuss them
On a broad scale, I'm seeing an ever-stronger signal for the jet to tilt NW to SE, followed by an amplified upstream ridge potentially reaching up to Greenland for a time, after which we look likely to see the energy driven down into Europe becoming quasi-stationary, with a high risk of dank, uninspiring easterlies due to a major lack of cold pooling over the near continent. If we end up in that situation, retrogression of heights NW will be the greatest desire for coldies - and would be entirely possible given the overall setup at play.
GFS gets the upstream ridges going sooner than ECM thanks to a trough tracking north of Greenland rather than right through it. ECM goes with the typical track straight on through, but has a very promising trough/ridge combination unfolding on day 10, so really it's just a variation of the same idea.
We still have more than a week of westerlies to get through before the currently progged period of changes, but at least they look to slacken off under high pressure at times next week. Not sure if it will be crisp and clear, though; the airmass source looks to be a mix of tropical maritime and return polar maritime... sunny spells perhaps? GFS shows a few ground frosts to be had.
Overall I feel that the signals from the models are typical of the run up to a cold spell, but that could be anything from 1 day to a fortnight in length as far as can be determined at the moment.
Originally Posted by: Stormchaser