ECM's in the flat-jet camp as far as the Atlantic goes, so Jacko's use of the word 'cooler' rather than colder might well be justified after all, at least for the coming 10 days or so.
There could be a silver lining though, as the storm of 9th/10th December still digs far enough south to allow the that flat jet to aim its sights at the eastern Mediterranean (the band of green on the below chart provides a rough estimation of the jet path):
This is where I was harsh on the GEM run earlier - it doesn't deliver from the northwest but it does get low heights to the eastern Med. very effectively indeed. ECM lifts a lot more of the low heights out northward from the storm of the 9th/10th, taking until day 10 to produce the right setup for a more significant push SE from the UK.
I'm not convinced that we would see the higher heights extending NW from Scandinavia for quite a while after that ECM day 10 chart though. Too much progression of the low heights from the Atlantic to Siberia.
Looking at JMA's day 8 chart, the trough behaves similar to the GFS 12z op run, but the strong mid-Atlantic ridge is absent. Probably headed somewhere between the ECM and GFS output which would be often wet and windy and without the height rises to the east. I imagine that would have some members turning back the clocks by 12 months
Originally Posted by: Stormchaser