just like the good old days😀

Some incredible output this evening again

That's pretty much my concern Darren.   We all know how rare it is to get all the parameters correct for a decent snowfall and the 12z GFS run demonstrates that perfectly.

But as you say, the detail will change from run to run.  The bigger picture at least is that we're heading for colder weather; whether it will be very cold or something less remains to be seen but at least we'll get below normal temperatures for the first time this winter down here.

Your part of the world desperately needs to dry out so you should welcome this.

Even if, you miss the snow altogether.

A perfect snowy GFS for some. And with a slight adjustment southwards, it would be perfect for us S of the M4. Time will tell!

Where is the " Like " button!

control thus far n/easterly setting in?

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=174&mode=0&carte=1

had a quick scan through some of the ens. I think we'll find a lot more scatter than this morning's set...

EDIT: Start of FI and this is actually some mean to behold: http://www.meteociel.fr/modeles/gefs_cartes.php?ech=192&code=21&mode=0&carte=1 

I think I might be getting caught up in superficials along with some others - the lack of yellows in the north atlantic and southern greenland seem disappointing, but that doesn't mean the overall pattern isn't equally conducive to something as good if not better than what was shown earlier..

AH this is too confusing. I'm off till the 18Z. Mild cluster definitely coming back in the ens. need to watch. other operations gone against GFS tonight though, so lets see where ECM lies in an hour and what the 18Z does. 

I'll bank the GFS 12z from a NIBY stand point.

Another Narnia type run from GFS but this time the back of the wardrobe is situated somewhat north of the M4.

Looks like it - there are quite a number at 240 with even milder temps down here than the operational. The majority are still cold, but the milder cluster is certainly gaining strength this evening as far as GEFS goes! Of course anything that far out is all moot anyway, but there must be something that's being picked up much earlier on to generate the change.

This is, of course, the great risk with a northerly. We do need lows to encroach in order to bring moisture if we want to see snow inland, but equally well just a few miles too far north and it's a rainfest for some. Too far south and only the southern strip gets snow...

There's also the risk (as shown in several ensemble runs) that a low actually makes it on an NE'ly path and brings a return to SW'lies.

Thankfully it's all too far out to be a great worry.

Indeed my concern is that the mild air could push too far north and lead to more copious rain from Cumbria and others that dont't need it if things go wrong. Thankfully this isn't showing at the moment but the trend has been to rise SLP to our South which MAY encourage the Azores low to move North.

We need SLP to remian lower over Spain if this is to be a countrywide cold spell that is long lasting, if not it may lead to only a transient cold spell although a good snowfall in areas. However if pressure does rise any subsequent return to cold would depend on heights over Greenland. The GFS has a mighty Greenland high but will it be that strong?

On the flipside if the low crosses the channel then that would leave some pretty damn cold air in its wake.

Still this cold spell remains poised the Azores low is the wildcard, for northern areas it's definitely looking good at the moment.

The trigger for these much milder runs from the south is the weakening of the Mid Atlantic ridge from Greenland.  In those runs where this retreats north to Greenland,  there just isn't enough time to establish a coherent N flow over the UK before low pressure arrives from the SW.  

We end up with a lovely Greenland High, but it's just too far away to keep it cold for the whole of the UK.

Where the ridge is maintained, we get enough of  pressure gradient W->E over the UK to drag cold air all the way south, AND deflect the low a little further south.   

Worth keeping an eye on in all the model output.

Control has full on SWerlies by the 21st too (without even a breakdown snow event, as the low approaches on a NE trajectory).

In the NH view you can see that the GH retreats all the way to Canada and dies over there. The vortex is fully reinvigorated by the end of the run.

http://modeles7.meteociel.fr/modeles/gens/runs/2016010712/gensnh-0-1-336.png

Ok, so this is a considerable downgrade for Sussex.   We were seeing good 45% - > 35% snow chances this morning.

This uncertainty must be what MOGREPs is picking up and not allowing the met to be more confident on a prolonged cold spell.

You can see why the Met Office still talks about westerlies likely to be re-established by the 21st.

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=272&y=22

Leeds - not too bad, actually an improvement on last night's 18ZEFS, albeit a downgrade on the best set of the season this morning. Certainly the further south you go the less pretty the picture, which always gets me worried