Well the risk is the low positions itself too far west and we stay in the modified flow for longer. It would be unusual but I wouldn't put it past it the way winter has gone so far.

I was thinking the same, let's hope it's the second one for Wednesday! Just had a quick flick through the charts on wetter and the agreement is good for this upcoming cold spell, in terms of when and how it starts, but how it progresses is less clear cut. ECM shows a northerly flow maintained throughout, whereas GEM shows high pressure sliding across us from the south/mid Atlantic.......I hope for prolonged personally😛

Of course this is looking at the 12zs, with 18zs out soon could well change......

Its nice to see such a powerful event being forecast at quite a short timescale.  Looks like its going to begin in a very strong northwesterly snow showered format.  That cold front ploughing through on Wednesday will bring a whole host of weather features, and i suspect may even get a thread of its own to study and track.  May even get some rain to snow in some parts as its chased into the southeast.

After that - things concern me a little... this chart sums it up :

Lots of diluting of the cold as we saw with the recent cold spell.  I fear this may also taper off quite quickly into a messy marginal setup unless we start to properly tap into the cold potential to our north .

Seems we lose our connection to the very cold pool of air to our north very rapidly.

This should put a smile on a few faces. 

That'll cause the daffodils to burst forth if that actually came off.

Actually - this poses a much bigger point.  Ignore the fact we may get warmer temps... That Azores high has finally lost its anchor, and the charts are happy for it to move away from where its been haunting for the past 2 months.

This is much bigger news than how warm it will be - will be interesting how the charts handle this bit of analysis on the next few runs.

Edit:  anyone got ensembles for Ponta Delgada lol

So that's it....  it's all over for this 'so-called' cold spell ........   that's the cold spell that's still nearly a week away from starting (if it does) following a milder spell that's following the tail end of the current cold spell we're coming out of. 

Seriously though, much as I'd like a wintry blast, it does look very pleasant and spring-like!

Those are stunning charts. 

Sadly, they're about as likely to be accurate as any other chart at that range. I won't be digging out the speedos just yet. 

Looking for warm synoptics at the far end of La La Land is as ridiculous as looking for cold ones IMO.

Still this is the model discussion thread as someone will no doubt remind me shortly

We might be close to cross-model agreement, but we certainly have not got intra-model agreement.

Just had a look at the short GFS ENS, and at +180 they're is quite a scatter of options and not all agree on a Scandy low set-up and mid-Atlantic ridge.

Beware the Trojan Horse!

ARGH ha! But I was informed to ignore those FI charts.

GFS still brings snow showers across large parts of the UK Wednesday evening through Thursday and into Friday.

This happens as a result of the air mass being both a little colder and a fair bit more unstable than was seen early this past week. The most notable difference seems to be lower dew points. A benefit of having sourced it from an area of uppers of below -30*C over Canada on Tuesday, this cold air mass reinforced to some extent a flow coming in from the NE, having across the length of Greenland, on Wednesday.

The situation actually looks more positive for cold enough conditions across the south on Thursday or Friday (depending on which model you look at) than further north, as this is where the air mass remains the most 'pure' with the least mixing thanks to a fast flow around the western periphery of the low. Northern parts see the center of the low very close by which allows more mixing out of the cold air to occur.

...but will there really be as much shower activity across such a wide area as GFS suggests? Recent experience of (admittedly less unstable) cold NW flows suggests not, with showers tending to be fairly well scattered. On the other hand, the signal for showers across much of a 24 hour period from GFS means that even a hit-and-miss situation could still deliver something to the majority of places within the region.

It will be interesting to see how close to this initial assessment conditions end up being. For what it's worth, with an outcome close to the above, I'd expect many areas to see a cm or two Wed-Fri, though settling is not guaranteed. Lucky spots (happening to catch a particularly heavy shower or a chain of them) would probably see more than double that.

Yes - But Met Office and BBC hasn't picked up on this - BBC forecast did say it will take a while for the cold air to reach the south but all of Wednesday into Thursday looks very wintry:

Sleet and snow - almost everywhere:

Rain and sleet showers finally turning to snow over lower levels in the south and reaching all areas by Thursday lunchtime!?

I am going to take this as a foot of salt after some charts/runs a week or so back which initially forecasted a period of "sleet/snow" and BBC saying potential for "Significant snow for the south" (During last weekend Sat night  into Sun morning), which as we know - failed to materialise!

ECM at T168 this morning:-

I think it is fair to say that low level snow is not on the cards for most areas during the working week this week. I'd still say cold rain for most but with some wintry ppn in the N at times and more so, on higher ground/hills. It could be until Sunday before the colder 850s start to flirt with the N. The ECM chart above would also suggest much dry weather down the spine with showers along W,N,E coastal districts. Usual areas exposed to the N wind will catch some snow showers too - eg Pennines, NYM etc.

Even a NW'ly component for me on this chart  

As Neil infers, patience is the key here. Consistent run from the ECM again.

I am sure I read somewhere that if you have very cold air at the 500hpa level as indicated by the charts that it can lower the snow level if the thicknesses are not that especially cold near the ground.

I can't remember where I saw it.

ECM ensembles this morning remain on the cold side for late next week - and maintain cold conditions out to day 10 at least...

http://www.wetterzentrale.de/pics/Rtavn1203.gif

http://www.wetterzentrale.de/pics/Rtavn1205.gif

http://www.wetterzentrale.de/pics/Rtavn12017.gif

http://www.wetterzentrale.de/pics/Rtavn1201.gif

Im confused, how is the above not cold enough for snow ( if there was ppn around) ???

 I can't remember yesterday's run in any detail but I felt at first glance that today's was colder?

I have to agree with you Michael

http://www.metoffice.gov.uk/public/weather/forecast/gcr01t9qp

Im down for a bit of the white stuff Thursday