Think its time for one of these threads. Ive been very generous with the bounds here, but I think its necessary to cover most reasonable possibilities. There is a small (say 10%) chance of snow even to lower levels tommorow if any cold air can advect from the north sea, before the band of precipatation clears. Thursday sees some polar maritime air mixing into our low, and precipatation on occluded fronts could again turn to snow, possibly more likely this time but still marginal. The friday to saturday period doesn't currently suggest anything in the way of snow, but I include it because of the nature of the frontal system. We have a strong ana warm front with southerly winds on its leading edge;it would not take much of an upgrade even now to make it cold enough to produce snow on its leading edge given that the cold air will only be half way across the north sea by then. 

And now some rough snow checking bench marks:

850hpa temperature:

-3C: Strong ana warm front or evaporational cooling event 

-4C: Well defined warm occlusion

-6C: Showers, cold occlusion or kata warm front

-7C: Cold front

-8C: Warm sector precipatation

500-1000mb thickness:

Roughly 534dam for Strong warm front, otherwise closer to 526dm. Highly variable. 

850-1000mb thickness:

129.5dm is usually an excellent benchmark for wintryness. <129dm would be almost definately snow.  

In evap cooling event may rise to 130dm.

Dewpoints:

Snow very unlikely if d.p >1.5C. Good benchmark is 0C in general.

2m temp

If the 2m temp is 0.0C or lower, check 925mb temp; if this is significantly above 0C expect rain or freezing rain.

If the 925mb is around 0C then ice pellets, freezing rain or snow.

if 925mb is below 0C then snow.

If 2m temp is above 0C then very rough benchmarks:

1.5C: Frontal based precipatation

3C: Showers that come from the north sea

5C: Showers from a strong NWerly wind in winter

8C: Showers from a strong NWerly wind in spring

Soundings

Provided by the GFS and WRF from meteociel or weatheronline.co.uk. Limited range and accuracy but more obvious whether rain or snow likely from size of warm layer.  

And to be honest, it is a bit hard to get that excited about this one when 1) it'll all be mostly high ground marginal stuff (cold rain for my locaton) and 2) another round of strong to gale force winds and heavy rain will come sweeping in from the Atlantic to shift all that in a blink of an eye.

But, hey, a change is as good as the rest, I guess. 

Might be, but considering we have only had 58% of the winter, there's a good chance it won't be.

There seems to be a perception on here that we are on the home straight of winter - I sometimes wonder if I haven't overslept and woken up on February 22nd, not January 22nd!

This thread started a bit early for lowland Britain?

0-3 days i.e. 22nd onwards, highland areas only

http://www.snow-forecast.com/maps/static/uk/next3days/snow

3-6 days, i.e. 25th onwards, and the snow spreads as far south as the Chilterns

http://www.snow-forecast.com/maps/static/uk/next3to6days/snow

Would it be worthwhile extending  the  snow potential thread to cover next week  which does seem to have greater potentila than this week.

Ferguson saying METO are only concerned about snow for Scotland and NE England for Wednesday. Then a return to zonal most likely as we have seen from the the publicly available output. MOGREPS only have 10% chance of an easterly later

So the coming period will be zonal but cold zonal and a good test to see if it delivers anything wintry away from the favoured locations.

further my post before

here is some Snow porn

http://www.bbc.co.uk/news/uk-wales-21910737

Mold received around 90cms in one night.  This area isnt on high ground situated around 100m asl.

Magical things can happen quite late in the season.

Left work to rain, which turned to hail and then snow. Some really quite big flakes and heavy snow near home for a time. Took a detour over the hill a couple of miles from my house. Snow is on cars down to around 230 metres. The snow started on the road at 270 -300 metres with a full covering and a temp of 0c. At 400 metres (the top of the hill) there was a full light covering on all surfaces. Can't be too clever on the Snake summit now

Just had a hail shower which, as it eased off in intensity, turned into a mixture of big fluffy flakes of snow mixed with raindrops - the first snowflakes I've seen this winter!

Before it started the air temperature was +5.6C, dew -3C. It's now +4.3C, dew -4.2C (according to my station, which does tend to report dewpoints a couple of degrees below the actual).

Here's a pic during the hail phase:

Had some heavy snow earlier, most of it was wet, however we had some small deposits on the car. Winter finally arrives!

Observed a sleety hail shower just after 6pm here. My waiting to see an actual snowflake this winter continues...hopefully by this time next week that wait will be over. 

I also saw a sleety mix in a heavy shower early yesterday evening. The question is... is that my snow lot for the season?