Well this is what makes model watching so good. Honestly like watching a thriller football match at times, flipping one way, then another. Fascinating viewing.
The intense cold is essentially dependent on the behaviour of that storm coming out of the US. Which model handles those most accurately? As the experts have said, ECM. The ECM shows that low heading south down the UK which results in a much better synoptic set up for us. Looks like the GFS has finally gotten with the programme and fallen in line with the ECM.
The UKMO is still the odd one out. However, we have an SSW, favourable teleconnections, low solar activity. It seems as though everything points towards a cold spell and because the ECM handles those storms better, and the cold spell is dependent on the storm, I think the logical step is to back the ECM on this one. Expect the UKMO to come on board soon. Nothing is ever guaranteed in this business but my eggs are in the ECM basket.