Snowly does it

The GFS to T132 ties in with the MetO thoughts with cold across the East remaining and attacks from the West as that low at T132 slides under bringing a slightly less cold bent to the west for a little while. Encouraging

Might be just me but I don't see it. Looks to me like the shortwave won't make it through? I'm at T96

Medium to longer term GFS atrocious for cold weather. T168 is a mild strait jacket. For sustained cold we need to see ensembles holding and backtrack continuing.

12z GFS falls apart at T120ish when that lp anchors round the tip of GL. We need everything 200 miles west and that to ride up the west coast. As itus, SWerlies and warm air knocking on the door by T150 and no clear route back. GFS still a Major concern for prolonged cold.

Much better by T120, the lp near Iceland isn't too much of a spoiler anfpd we are not setting the flattened Azores feeding SWerlies

Pressure over Scandi better, we might be ok. Too tight to call it from this run. Exciting, isn't it?!

T78. Houston...... This is going to go pear shaped I think, looks like we are being short waved into submission

At T72, shortwave in evidence, however things to the West look slightly better. Watch what happens around GL and the mid Atlantic to T96

It doesn't. The shortwave is just a disrupting shortwave which, if modelled correctly, could ear us back to a milder outlook. SSW is a potential boon for cold prospects as it will ear to te cold flooding out like an overfilled glass. However, it is not a joker and we don't get to play it where and how we fancy. It might do us no good at all.

Add to my optimism grouping the latest MetO 6-15 dayer

Reasons for cold spell pessimism - 06z GFS run goes against a protracted cold spell, with shortwave spoilers stopping WAA, Mid Atlantic ridge gets squashed into SWerlies, pattern shows no sign of breaking back to cold. Shortwaves modelled within 'semi' reliable timeframe Reasons for cold spell optimism - all the key models bar the recent GFS runs, ensemble average broadly supportive of coldish uppers, need to see where the 06z ensembles trend. Reasons for not wanting to guess - 'record model uncertainty' - that phrase in and if itself should be warning against even cross model agreement outside of about T72-96

South westerlies by Tuesday morning. Big backtrack but was always an option on the ensembles. Be worth looking at the ensembles again to see if the trend for many of them is away from what we want to see

-5s have cleared out of England by Monday tea time, and there's no chance of GL height rises saving this run. Make the ost of the weekends offerings and hope the GFS is over correcting with that shortwave business round Greenie

OK, weekend looking nailed on 'interesting', however there is still much to be decided about the situation next week. There are hurdles to clear before at cold air starts to lock in over us, and the ensembles from GFS show some of the problems. The last thing I want to be is a party pooper but don't forget we are probably more likely at the summit ignoring the precipice than In the pits staring at the stars. Enjoy the snow this weekend and fingers crossed for the war to develop in our favour next week.

Splendid snowy runs from the 12z suite, however I would urge a note of caution based on the GFS ensembles. Cold snap ON Cold spell still to bag. IMBY - :-)

A little confused by the reaction to the model output and the 6-15 dayer, which today suggests a cold and blocked solution Sunday to the latter part of the week followed by attempted breakdown from the west with an uncertain outcome. That's a description of pretty much every cold spell in the UK and is what the GFS shows, albeit with the milder encroachment failing. We live on an island artificially warmed by the gulf stream, that's what we get. IMBY wise I am very happy with the output.

Past T180 is complete nonsense. White Xmas not quite dead in the water (ice) yet

Yes, agreed. It's preferable without being ideal.

Surely that would just migrate into a version of the hair dryer anyway?

And here comes the +10 850s Awful prospects for cold and a white Xmas on the GFS. I rather hope it has muffed up the handling of things post t96 or so but a worrysome outlook with teen temps next weekend possible here

Be nice to see this baby Easterly on future operationals, with hopefully the second low pressure weaker and further south giving the HP a chance to build properly. Better viewing than yesterday's Meet The Atlantic

With any LP in the Atlantic we need it to cross us, or better still undercut us as the cold air will always be drawn down the western flank. If its in the Atlantic it can be any size it wants, it's of no use to us for cold as we're stuck on the east of it.

It doesn't even need to be much of a form horse really, high pressure over Hudson preventing WAA, blocking Siberian high too far east and no undercutting due to HP over Europe with a ridging Azores providing a ski lift for LP..... The forecast almost writes itself!! In other words, need one of those ingredients to change, and the more the better

Crumb of GFS comfort, the ensembles are not as terrible as the operational with some potential interest in te few days before Christmas. Oh we'll, that's the most positive thing I can find.

It will ride up drawing warm air with it I'd say