[Model Output Discussion - 28th November]

But 'so many possibilities' are showing just because its FI.

Well it depends what you mean by FI. If you think FI is beyond 100 hours then you're not going to believe a cold spell is coming until you walk out the door one day and see it snowing. The time period between 100-168 still has some credibility and it has to be taken with some seriousness. At the moment this time period is looking better than it was a few days ago, we have most of the models agreeing that the low that disrupts the blocking will still keep the UK relatively cold and that we will get a brief northerly from it after. A few days ago, GFS and ECM had that low tracking a lot further North and then showed mild zonal weather after that as a result.

[Model Output Discussion - 28th November]

I don't think there's much difference between the GFS a and ECM in mid-range and I think there is less difference between them than there is between ECM and UKMO. They both show high pressure building towards the UK with a deep low heading off to north scandinavia, which is how most Greenland Highs form and it's the type of thing we saw in 2010, 2009 and even 1962. In fact the set up ECM is showing in FI is ridiculously close to the set up just before the 62/63 winter got going (not making any assumptions here though haha). Either way, it's encouraging to see so many possibilities where we could get a good cold spell, unlike a few days ago were both ECM and GFS went for zonal.

[Model Output Discussion - 28th November]

UKMO once again keeping things interesting with high pressure building above it, unlike the other charts.

[Model Output Discussion 12z 27/11/2012]

Some small but great changes at mid-range. Looking good for a snow event on Monday in Northern and Eastern areas, plus the low is tracking 200-300 further south keeping us under some relatively cold air with most places staying in negative figures for 850hpa temps.

[Model Output Discussion 26/11/2012 18Z onwards]

Big difference is also a ridge of high pressure forming in the Atlantic at t150 which wasn't there in the 12z. We might (hopefully) see that push North and possibly link with a weak high in Greenland. Though of course this is deep fi considering the circumstances.