Radiating Dendrite

Heavy snow in Purley for the last hour. everything covered and roads appalling!

Absolutely chucking it down in Central London and really quite cold in the rain. I think we are in with a good shot later, even now you get a sense that evaporative cooling is already initiating.

Yes, the euro 4 00z is a little disappointing but looking at 850s and thicknesses they actually look a little better and from an earlier time. Personally think now is the time to stop looking at the models and start looking up at the sky!

Not a lot has changed on the Euro 4 12z - very similar to its early run.

It was - still the very latest I can view lol. Hopefully the 12z will be an upgrade.

Yes, ideally we need it to slow up and the heavier pulses come through after sunset. Think it will be a real now casting situation as the margins are so fine but some of the heaviest snowfalls have occurred under marginal conditions - 0.5c could make such a difference!

Just checked the latest Euro 4 charts and it is going to be a fascinating event and actually quite unusual for this past of the country. The precipitation returns are quite impressive, getting on for 30mm in some parts so it will certainly be wet! In terms of snow it is looking like a very quick transition as the distance between the higher theta, 850 and dew point values and lower ones is very little so once it starts to turn it will be a quick transition to snow. Current timings for rain to snow is around 4pm for the NW of London, 5pm for Greater London and 6pm to the SE of the capital and into Kent. Anybody with a little height (150 - 200m) could really hit the jackpot. I wouldn't be surprised to heart of places getting 15cm plus but it is so marginal! The one big positive is it will be heavy precipitation so evaporative cooling should certainly help.

Personally think we will all see falling snow - the big question is whether it sticks and how much. We also have a good chance on Friday morning and given projected temps for next week, anything that falls should stick around for a while.

Think ive just wet myself!

I think there will be some big surprises with this and I am fairly hopeful of seeing a couple of inches. I have seen many of these rain to snow events and believe me once it starts to snow and DP's drop it will readily stick. Poeple moaning about ground temps being too high - we have had a number of frosty days since the start of winter with ground temps staying below freezing all day despite air temps of 3/4c - I think the ground is plenty cold enough now. Finally, if the precipitation is heavy expect falling snow even before upper air temps are conducive for it due to evaporative cooling.

Because what happens upstream in the US has significant ramifications for what then follows on over the UK.

Because what happens upstream in the US has significant ramifications for what then follows on over the UK.

UKMO at 144 is pure bliss compared to earlier! Much amplification and that shortwave is going south. Over to you ECM.....

The med is the ultimate snow machine, sea temps currently around 16c and upper air around -10c = a 26c temp difference and bucket loads of snow!!

Firstly it doesn't have an 18z run and secondly next week has not happened so we have no way of knowing how well it has performed yet.

Completely agree northwestsnow - might still take a few runs for the GFS to come on board if it is wrong. It is struggling to resolve the energy at the tip of Greenland and goes a bit trigger happy with the shortwaves. It looks a little unlikely but could end up being right. Shortwaves in the local do tend to crop up.

Almost a mini ramp there knocker GFS still makes me nervous though. It is often derided but does have a habit of picking up a nuisance shortwave before the ECM and UKMO. The ECM looks very clean in its progression which is great but I still expect a few bumps in the road and a possible crash!

Thought there would be a few more people in for the ECM. It's an absolute cracker and continues the easterly theme towards the end of the run. It has good support from the UKMO and seems pretty keen on this evolution given the past few runs. Cold air never leaves the south once it sets in so any snow that does fall could stick around for a few days. ECM is the best run of the winter for me - cold and snow now coming into reliable and no breakdown out to day 10.

Where are you skiing in Bulgaria? We did Borovets in 2013 and conditions were similar to now (100cm+) on piste. We had a good week and didn't find the queues too bad. Personally I found the piste preparation poorer than the alps and you do have to watch for the odd kamikaze but it was good value for the money paid.

Thanks for the explanation Knocker. Hopefully we will see something similar modelled in the operationals soon.

Why is this interesting Knocker? What is it showing?

Thinking 4 years of no appreciable snow is now a dead cert. Fast becoming bored with having to heat the house for a covering of frost! Summer is quickly establishing itself as my favourite season. Even a poor summer brings 30c here on more than one occasion. Models are just dull to look at in the reliable at the moment. Anything past 240+ is just a waste of time.

It is a forum where people are free to voice their views, not a meteorology learning course. Perhaps you should look at the weather guides section for help or just pick certain posters and read only their views.

ECM brings in the second northerly, though it is fairly brief before the high starts to encroach back over us from the west. I found it interesting that the GFS once again went for the easterly in deep FI, this has now been shown in some form or another for the last handful of runs. This is probably as big a trend as you would ever get from the model in FI land. GFS FI is usually characterised by big swings in synoptic patter from run to run, so for it to keep landing on the same sort of solution is actually fairly unusual. Personally, I think we will eventually end up with the high back over us, leading to cold and frosty weather. What I have found with our weather over the last few years is that it has become very "stuck in a rut", a synoptic pattern tends to keep repeating during a season. This has been in evidence the last few winters and this winter seems to very much be mid-lat highs either over us or just to the SW / SE with lots of dry weather with cold and frost in the air when we bring in a slightly colder feed or inversion. Think we may be stuck in this pattern for a while yet, it could be worse I suppose.

I don't see anything sinking at 144 on the UKMO - though the GFS medium range is 100% accurate after all