These charts from 1966 give an indication of what is possible based on the parameters that are presented by them.  Agreed, they do not present dew points, lapse rates etc, but the 500mb charts look about equal to what is being predicted by the GFS on Saturday in the West of England across to South Wales  and at this stage, in this area the 850s are predicted to be substantially lower on Friday .  I say this because in Bristol snow started to fall on this day at around 8 AM and continued well into the afternoon depositing about 4 inches. Now this was April not January, or even February, precipitation started as snow, and was entirely within daylight hours.

1966

http://www.wetterzentrale.de/pics/archive/ra/1966/Rrea00119660415.gif

2016

http://www.wetterzentrale.de/pics/Rtavn1141.gif

1966

http://www.wetterzentrale.de/pics/archive/ra/1966/Rrea00219660415.gif

2016

http://www.wetterzentrale.de/pics/Rtavn1142.gif

This is not meant to be a conclusion but merely the presentation of an example to show what is possible.  This post is purely related to frontal precipitation.  I say this because I feel that the arguments presented on here relating to snow risk in the up and coming spell have been rather confused as members in the North and Eastern camps have tended to assume the case for showers and those of us in the South and West have tended to discuss the frontal variety.  With respect (I am not an expert, just an experienced observer and model watcher), I feel that the cases presented do need to include specification of the exact weather type in question.  

Thanks Dave we get the point

Mine duplicated earlier not sure why though?

I think this is a fair comment, although both modes (eastern convective, SW dynamic) look right on the marginal so I'm not making a distinction - well maybe not yet. Come Thurs/Fri we'll have a handle on the dynamic influence from the SW. And then a day or so to think about convection, if any occurs.

I like your 500mb matching, but taking the general synoptic set-up in isolation is a bit like calling one bean on toast a meal.

Nice update for the week ahead. Meto going for snow showers in the East once the easterly kicks in. One too watch.

http://www.bbc.co.uk/weather/features/35636442

Defintely an issue with posting it seems to get stuck when you hit post?

My problem is there are 3 significant differences here:

1) Wind direction in the 1966 chart is more definitely north easterly rather than an easterly. Its a surer way to deep cold.

2) The LP in the 1966 chart is a fully blown atlantic depression with extremely well defined fronts and is in a mature rather than decaying phase - intensity of the precipatation really matters I think, well defined fronts can cause alot of snow. We have a very weakly defined occluded front (see my front overlays)

3) Precense of warm seclusion, note that in the 1966 chart the centre of the LP is not over the UK, the precense of an LP centre causes warming always this is regardless of the presence of a warm sector. The problem is occluded depressions have a small warm core; when that is over you it isn't great at producing snow. Northerlies are okay because the warm seclusion tends to be over the north sea, and channel lows are okay because the seclusion is over the channel.

My honest view: Saturday will dissapoint you all. There is no energy here, frontal debris is never going to give significant or widespread snow.

I completely agree with you, and this is why I really wish people would break their dependancy to 850s, they are intended as a guide only. The most useful model charts are SLP+500hpa, there is no long fetch NErly, and there are frequent incursions of eratic frontal systems from the atlantic; sure the 850hpas might be cold but there is no time to get the cold feed down to the surface before it is cutoff. To make things worse these frontal systems are kata, weak, decyaing, frontyltic occlusions which will produce patchy rain and drizzle.

A good warm front or warm occluded front coming into cold air is what we need or a NErly feed that lasts more than 2 days. We have neither.

This is going to be a bust until this changes, and Saturday will be a bust unless some energy is injected into that pathetic low.

With regard to the above I want to make it clear; I am not saying occlusions cannot give massive amounts of snow. On the contrary the ana warm occlusion is perhaps the biggest snow bringer in the UK. But this is the case for fronts that actually represent a meaningful boundary between airmasses whether its at the surface or a bunch of warm air has been lifted aloft. I see an initially well defined occluded front pulled and stretched out with some energy going north and most going south while a warm seclusion develops over Ireland. This is not what we want. 

Re comments by Quantum on 1966 comparisons.  Agreed, as I mentioned the comparisons only tell part of the story and to actually expect expect 4 inches of snow is pushing it a bit, but I am not writing off the prospect of any at all as forcing sometimes comes into the mix quite unexpectedly and it is not totally clear at this moment the precise direction of energy transfer, (could even force the milder air back northwards across the South as per GME, JMA and Navgem).  Along the way you presented the problems far better than I could have and in fact this has IMO brought more clarity to the discussion, so thanks for that.  

No problem, I think for the event to be more than eratic patchy rain and sleet the low must change not only its location but also its shape.

A great irony in all this is that the warm sector is just too far south. That's a complaint you don't hear often but I think its true, when the warm sector is 'too close for call' but doesn't actually go over you that can great huge snow events and subzero maxima. The trouble is the warm sector is dissapearing into the south mediteranian and taking all the energy with it. A warm sector is well defined and only causes problems when you are in it, a warm seclusion on the other hand has really no positives unless you directly compare it to being inside a warm sector (when the change of snow is zilch). 

Will it or won't it?

From IF

if anything, tonight's EC Monthly - which, like GloSea, has performed well this season - adds further weight to notion of a chilly start to Spring.

It has markedly strong -ve temp anomalies end of Feb & 1st week March, and then retaining (albeit weaker, but that's normal as lead time extends) -ve anomalies right to 3rd week of March. Equally, it shows blocking initially to W then becoming dominant to NW later, with - and this in key contrast to last Thurs output - a drier outcome generally but notably so by 3rd week as signs of NW block establish. This *may* be the model toying with SSW impact. Not sure. Flow throughout is broadly from N (from NW phases at first to more N/NE'ly after mid-month). So nuances aside, it certainly doesn't look mild: at least in *overall* sense.

Met Office today retain the broad idea of a prolonged phase of below avg temps into at least early March, possibly further, and EC will undoubtedly strengthen their view. However, GloSea5 *had* been (I haven't checked today) less bullish on colder weather a bit further into the month. Hopefully it's right...and spring can get running after only a temporary chilly start! We shall see.

The difficulty here, communication wise, is that some people (not just elements of media) run off with ideas about 'below average' equating to the exceptional conditions of March 2013; or being some coded forecast for Snowmageddon/Big Freeze. Neither are true, of course: we see nil exceptional re severe cold looking ahead. But clearly, snow could be possible. That's not a core part of message until much shorter, reliable lead times. 

Yep, On Friday and Saturday The UKMO and GFS looking much the same, there looks to be some cloudy and cold weather but not much snow potential on Friday and Saturday, the 528 dam line and the -5 to -7 at 850 hPa not close enough to the Cold Pool that from Friday to Saturday looks like may affect the far SW side Froday night, and main focus on Cold and Warm/ Occlusion goes to West Spain and West Central France Friday night and during Saturday.

It looks to some extent similar to 8 days to 9 days ago in Sat/Sunday before last week!.

And by this coming Sunday and first part of Monday, and from Saturday night that the Colder air finally returns back after what it looks like it eases on Friday to Saturday teatime..., the 528 dam line just moves away as the SE winds push in, so it then seems by Saturday we could be seeing cold rain with hill snow ahem.

On the other hand maybe some beefy heavy blustery cold sleet and snow showers from 00z Sunday to 00z Monday or 12z Monday could give us Sun 528 dam air and -5 to -8 at 850 after 06z Sunday a.m.

It looks good for SE England and my area on Sunday, but I think the  wintry showers will either hit or miss the location in E London, unless there are east-to west moving through Central London, if they com along with NE winds the hilly areas catch them!.

😆😃🌤.

Ps. Someone tell Brian to reboot the server!!!

Agreed.  Looking cold, but not spectacularly so as in 2013.  However, meteorological spring will deliver a winter's tale.

Reply from Weather Idle

Agreed.  Looking cold, but not spectacularly so as in 2013.  However, meteorological spring will deliver a winter's tale.

Yes, all you can see for the foreseeable is intermittent northern interruption, rather than northern blocking.  The mobility of recent winters has been astounding.  Blocking of any type has been hard to come by.

Agreed

Looks cold for the next few weeks

I think borderline not just for you but most of lowland southern England to be honest - good synoptics but as Quantum and others have posted it just doesn't look cold enough to deliver in the South. Maybe further north and on high ground a chance of some snow, but all a bit of a wasted potential really - I think a lot of people would just prefer some spring warmth now if we can't have proper cold. Looking at the output this morning no signs of that currently - I think cold and frosty with wet (at best sleety spells) away from the high ground is most likely.  Nice to be surprised but I doubt it.