john w

Those wanting a red warning...you know it doesn't actually change the amount of snow that will fall. That's down to the physical now cast this has now become. So the radar rather than any red warning is your friend/enemy. A northwestward movement must surely be due now.

Dave, Either I've lost me marbles or this is way east of where It was meant to be. I seem to remember a potential band this morning. This then concentrating to the SW (what is in the present red zone) until about 2-3 in the morning. With another band then following up tomorrow. I do seem to remember one model throwing things a bit further east. But not this much and for this long?

Enjoy it guys and gals. On the train east to my weekday location (london) and it's just grey here. Hoping for the bonuses referred to last night!

Nope

Caught the train to London...may have been an error. But a good 3-5cm in places on the walk in and light snow at ascot. Hoping today people stay safe. Not sure how much to expect here yet. 5-10cm seems about the mark

Couldnt have put it better myself

The stuff in France is NOT the main low, it is convection and a weaker front ahead of it. That band may give snow slightly further East than was expected but to put your minds at ease the 18z Harlem, the same model everyone on other side of the A3 are raving about shows this: That was always the main event, anything earlier is bonus, anything after is a bonus (and I wil probably be banking on the bonuses rather than the main event). People will always post the chart they want to see....well, most do.

Im looking out for BB1963's second post, has he done it yet. It is finely poised but I cant see this going pear shaped and I really am a sceptic.

Some perspective time and I lurk here a lot. The Aperge and Harlem 18zsssss have NOT pushed this east, they have extended the precipitation eastwards. More East does not mean less west unless your right on the tip of cornwall. Shower activity in France will be a great deal convective as well as frontal. Looking at the radar I cant see the low is much further East if at all, than forecast. More of its boundary airmass may be being disrupted, but that doesnt mean the track will change. The only fly in the ointment I can see is the 18z GFS brings warmer air slightly further north, but even that away from the very south coast means any of Fridays evening secondary feature coming up may be marginal. The geographical coverage of snow looks to be broader, but the sweet spots I would say are still where the Met think they should be. (I also think they would have been extremely careful to have amended the warnings and forecasts for the 10:30pm regionals and they would have had Harlem and Aperge at their disposal. The SW still looks poised for a great event...just more in the East (and I would include myself in the latter) look like also JOINING in on the fun, not taking it.

Never trusted these but it does show the m4 snowshield being obliterated

If your in the coppid beach or Hilton you can always pop to the John Nike ski slope!

M Great Reading David. Look forward to later. The depth of the atmosphere is always great to see when you see clouds moving in different directions on the IR and helps explain fronts too. Great post.

I spotted that on some of the models this morning...just about spitting out that secondary low. Interesting stuff.

That almost has a A329M snowshield on it

Nice summary Gibby. I have been trying to look at the t0 low on the 00z suites and compare it to the 12z suits from yesterday e.g. t+12. The GFS had a 978 low just about over the Azores at t+12 which is almost identical in form on the 12z. The ECM and UKMET does not offer a 12 hour timestamp on the sites i use AFAIK so cannot compare. Aperge is a tad southeast of where it thought the 980 low over Azores would be. Interestingly the disruption to the low on the ICON looks to be flattening it someway South when compared to the has. ICON almost mirrors the GFS and is close to developing a secondary feature east of the low. So the low in my view is going as expected. The next 12 hours will be key as to when it begins to turn and head north then (and it isn't often you say this) northwest. I wouldn't want to call it but I can see the disruption against the cold air flattening the low a bit more and therefore extending the coverage of the showers slightly further wast. But I think the met have this pretty well thought our now. Draw a line from bournemouth to Dublin and i think your in for a memorable event. My area...be hit and miss. 50 miles further east we will get a pasting too. Present track...a small covering (5cm)...much further west...probably similar to last night's. I'm too drained to look at the secondary feature.

Had me 0.01mm of snow here in good old bracknell. Never quite sure whether we belong in central South or South East tbh. Friday looks like delivering 2-5cm at present. But other than that I'll take the hat and scarf weather and the sunshine before we head in to spring. Be interesting to see who gets what from Fridays event though. The sw looking most favourable from the majority of model outputs. But a 100 mile shift in a any direction is entirely plausibleat this stage.

So the beast arrives. Had a walk to the station this morning (Bracknell) cold. The most memorable thing this week will be the cold and windchill. Now on the train to London. It is getting cloudier but no sign of the snow yet. Just near staines. My patch of Berkshire can do well out of easterlies if a Thames streamer get a going or a channel low incursion or shortwave gets set up. The former seems a good possibility today in tomorrow and we may well get some carrying snow from the northeast tomorrow. I notice the warning for me don't cover my area at all, all week Friday looks to be the main event. Models really differing I'm what will happen. For those watching. The meto is the one we want to come off. Though all would give snow for a time or all of the time in my patch (and I'm just South of the heat element that is the M4.). Enjoy whatever it brings you.

I am inclined to agree with this. The GFS evolution is quite interesting if you look in to it a bit too: Shortwave over northern greece that seems to be thrown off from the low heading northeast on to Russia: Some time later it causes the formation of a small high over the adriatic/balkans at the exact time the low is coming in over iberia...Almost a mini block, in itself crucial as it sets the direction for warmer air: By Friday there is a sector of warmer air pushing in to the cold, but, the low already begins to close this off with wraparound. Leaving a knifedge -4 850hpa isotherm that could replace the M4 on a road map on Friday lunchtime Two key questions for me actually are: 1. How much will that shortwave actually cause the formation of the mini high and....will the low bow so easily to the presence of that weak high over the balkans. 2. How far north will the warm sector get, it will be heavily modified by the microclimate of the alps. Note, this is just me trying to explain what I see...it is not a prediction. Any thoughts on this also appreciated.

I remember that channel low from the south 2010 i think. The red warning moved west and South 6.hours before the event. In these setups nothing is set in stone. I may be wrong on the year. But I remember it Well!

In the hole near reading...

Wet covering here in bracknell. I reckon we managed 5mm. Just South of the m4. Light breeze and a bit of rain.

Well Ill happily eat my hat from earlier on. I thought the first band would fizzle and leave the main affiar for the stuff in the channel now. We had some very intense rain for at least 30 minutes, extremely gusty, if anything there was an element of rotation, but noting major and certainly nothing to hot the ground. What must have been impressive was the height of the system, Despite extremely frequent and bright flashing, the vast majority was intracloud and the actual loudness of the claps was rumbling rather than the sharp cracking you get when it is lower. I am not surprised it has disrupted Heathrow's easterly ops tonight and they will be playing catchup for an hour or two I suspect. The stuff in the channel now has some real potential I suspect.

Well there could be some surprise inland intensification and uplifting, but I reckon you're right. Fizzling out instead of intensifying seems to be the trend.

So so far today the Gfs and ecm have both returned a mobile pattern for the 19th. The Gem stays put at mobile and the uk met continues its trend of sinking the high south (someone seemed to intimate it was going with the ecm and gfs high solution) but I disagree thinking it was shifting south. I wonder if this sudden change is due to models getting a handle on upstream changes. But still its quite a dramatic change from 2 of the big 3. I also wonder of the gem has some real good embedded code and dynamics for handling the virtex compared to other models. it seems to have done well from time to time. We await next week but one must not complain. This week has been crisp first thing but extremely pleasant

Interesting how the GEM keeps to its bones. I have a small want for some unsettled conditions near the alps w/c 15th. But the main dynamic in the models seems to be if and where any high builds to come this time next week. The GFS has flitted between it centering over the UK, Eastern Europe/Scandi...or the pyrenees over several runs now (post t192) making it hard to draw on any consistency. I dont want to try to predict what may happen but I agree with Damianslaw that a sustained settled spell is only progressed on the GFS and it keeps flipping to where it wants to take it, questioning the length of any 'settled' spell. But we must put things in to context. Even if it is not 'settled' by comparison I expect it to be drier and much less windy than it has been of late, with conditions being much more near average as opposed to record breaking.