Higher Ground

Though 216h to 240h is pretty bizarre too. Been a while since we saw a deep(ish) low between southern tip of Greenland and Iceland (I think?). Another scenario for next pattern change hinted at?

ECM 192h to 216h wins my award for most unexpected evolution of the week (SW-NE tracking low evaporates, only for the next one to intensify towards the ESE towards the Pyrenees )

I've noticed that in the latest runs, GFS appears to have consistently higher pressure over Greenland than UKMO, even from T+6 hrs (when it's 1030mb+ on UKMO but 1040mb+ on GFS). Don't know if this is just some artifact, or whether there really is that much uncertainty about initial conditions. Though I think I've heard that the initial conditions fed into models are if anything the most critical factor in accuracy further down the line?

I have been wondering if the models have been somewhat flummoxed by the SSTA patterns. http://weather.unisy...e/sst_anom.html In very simplistic terms, it seems to me that if a low pressure is likely to take a path along the lines of that currently projected by the GFS for Monday, then the colder than average SSTA's along its path would imply the tendency would be for it to take a path even further south than the models would "normally" project, other things being equal. Whereas if it were likely to take a path towards the NW of Scotland, the warmer than average SSTA's it would encounter would imply the reverse i.e. a tendency for it to take a path even further north. Hence the vulnerability of such a set-up to small initial changes/perturbations resulting in large variations in low tracks. This is just speculation, an invitation to someone with more expert knowledge than myself to suggest if the SSTA pattern might be of any relevance? Hmmm just seen GFS +114: not sure i'll get any replies to this as i fear it may be buried under a stack of over-excited snow ramps! (Edit: far south of England snow ramps; obviously now risk of being too far north even here in Midlands, but can't complain too much given we've done fairly well already...)

Centred over S Coast instead at T+78. (Or to be more precise, secondary low pressure centre failed to form to north on this run hence less deflection of jet stream to north?)

I've just been playing around with the winter (Dec-Feb) CET figures since 1660 on Excel. If the CET for Feb 2010 were to end up at 2.8C i.e. the current figure (fairly realistic as things stand), the CET for this winter would be 2.43C. This would have been colder than average for every 10-year period in the record, except for 1675-1684 and 1676-1685. [N.b. equalling 1677-1686 average.]. And at least ~1C colder than the average for any 10-year period in the past century. Also, to cherry pick an interesting fact, even in 1940 it would have been the 3rd coldest winter in 45 years. Further, it would bring to an end the longest run of winters greater than 2.5C in the record (1980-2009 i.e. 30 winters). Same with the longest run of winters of 3.0C or greater (1987-2009 i.e. 23 winters). Though interestingly it would also ensure that the longest run of winters *greater than* 3.0C in the record, that is 3.1C or above, remains 1896-1916 (i.e. 21 winters) for at least a couple more decades! [Coldest winters between 1896 and 1916 were 1900 and 1907 with average CET of 3.1C, whereas in the last 20 years both 1991 and 1996 had a winter CET of 3.0C] Just a bit of fun! (And perhaps worth double-checking as i just calculated all this quickly in a spare moment).

Snows of 1990/91 winter set a benchmark here still not equalled since. The Dec snowfall produced over a foot with drifts over 2 foot, all in one go (overnight into the morning). The Feb snowfall was virtually a foot as well - 11.5 inches i seem to recall. And both Dec and Feb snowfalls brought similar amounts to lower ground too i think. In the past 2 winters i don't think there has been a single fall which has produced more than about 5-6 inches. The accumulated totals have been pretty good here on the Lickey Hills though (often right side of marginal compared to lower ground). Last winter peaked at 8 inches/20cm depth (Feb 2009), and this winter at 10 inches/25cm (Jan 2010). We're currently back up to at least 4 inches/10cm as of my measurements half an hour ago, Feb 18th 2010 Will be out sledging in the next couple of days without a doubt! [Edit: just to be pedantic i'm pretty sure the blizzard was on 8th Dec 1990, rather than 12th]

Pleased for you! Even looks like PPN over West Mids has intensified slightly in places over between 6.30 and 7pm judging by raintoday radar! We're doing just fine here too

Thanks! That would have been bugging me otherwise!

OT but why? I'm thinking that even when it's 10cm, they still have to clear the lowest 1-2cm if you get what i mean? Edit: scrub that, re-reading the original post i think i get it now! just being thick.....

After all the fuss about the GFS and UKMO, the ECMWF takes the low further south at T+96!

Got close to the predicted 10cm here

To be fair you and others have seen this coming (just outside the reliable timeframe, or even occasionally within!) for months LOL GFS +180 and jet continues well south after all?

Yes, fair enough. I just checked the UKMO and it's quite a sharp left turn from the low between +72 and +96 hrs. Sure, if that happens, it's likely a major step towards a more "normal" atlantic pattern. *If* that happens.......hmmmmm...... but then it is well into the traditionally reliable timeframe. Wouldn't want to call it just yet considering all the talk of fat ladies entering the building the past week, only for it to turn out they couldn't make it through the marginal snow.....

Just to clarify you're referring to the chances of a snow event on a particular day right? I got the impression you meant the whole extended forecast has shifted dramatically away from cold, but I'm glad I just looked at the GFS charts myself on Meteociel because e.g. at +132 it looks even slightly better, rather than worse for cold/snow, no?

Winter wonderland - temp finally went below freezing about half an hour ago. Been treading water with 2-3cm of snow on top of Beacon Hill (similar to yesterday - seems that the snow up until half an hour ago almost exactly topped up the existing snow as it melted). Was interesting half an hour ago to see a clear snow line half-way down the golf course - at about 240m or 800 feet altitude. This means that most of of the sledging run should have a nice icy base! Shame that snow is back to just light/moderate, but seems there's plenty more to come?!

I agree - although it's been snow all the way here, it's amazing that it's settled in Worcester but not here. Never known that to happen with frontal snow, especially coming from south. I guess maybe due to the complicated way the cold/less cold sectors have been wrapped around the low pressure area given the existing circulation from the original low..... Edit (just seen previous comment) - it's certainly been pretty intense here, just not quite cold enough to settle

Well obviously very lucky to have been just the right side of marginal here yesterday, because just the wrong side so far today. It's snowed all the way through, and pretty heavily for at least the last 45 mins or so. But just not quite managed to settle properly, even though it looked like it was starting to. It may have accumulated a little on the top of the hill where there was already 2-3cm from yesterday, but other than that I'd say about 5cm of potential accumulation down the drain so far

*JUST* about starting to settle, and that's after probably 10 minutes of heavy snow with huge flakes. Much more of a struggle than i expected.

Just checked the latest temps here http://www.trafficweather.info/roadWeather/rwisMap.jsp Unusually, given PPN coming up from south, it's significantly colder at Fish Hill in Cotswolds, than here, so that's a good sign for shift towards accumulating snow i reckon (hope?)

Seems like you've been in just the right spot for the heavier stuff!

Hmmm the intensity seemed to peak around Evesham/Stratford; and still no sign of eastward movement? Though at least a new trough forming behind first line. http://www.raintoday.co.uk/ (enter postcode on LH side)

Darker again to south, hopefully bringing heavier snow again as it's gone back to light here. I think even at this elevation it's going to take prolonged heavy snow for it to settle significantly. (Though we have an icy covering left over from yesterday on the grass so showing more signs of starting to settle there at least).

OK the serious stuff has been here for a few mins now, with some huge flakes. Barely settling though, could be more marginal lower down than hoped?

It got moderately heavy here, now gone very light again, so the main intense part of band still not here yet - therefore will be a while yet before it gets to central Brum etc... (Assuming there is more intense snow still to come? Sky looks a fair bit lighter to the S again )