virtualsphere

Free online if anyone's interested: http://onlinelibrary.wiley.com/doi/10.1002/wea.6080581205/pdf

Yes, noticed on the GFS that 850hpa temps moderating after tonight, highest on Friday and then drop back below -5C on Saturday morning. Possibly a nice set-up for those of us in SW Wales on Sunday if the wind aligns in a favourable position for those showers to come off the sea in the colder air, GFS 18z looks good for this, but plenty of time for changes before then in this kind of pattern. After getting thundersnow from a south-westerly a couple of weeks ago, anything seems possible!

MetOffice weather maps have a fairly straight westerly overnight, also moving to more WNW by tomorrow lunchtime. Still more of a westerly than northerly component up until Friday morning though if these are to be believed. NW / Northerly then lasts Friday through until at least Monday.

2.6C for me please.

5.3C please

It was certainly a great snow event but don't envy you having to work out in it! I've posted this news article before in a different thread, but worth another mention http://news.bbc.co.uk/1/hi/uk/6338151.stm Here in the west the cold only lasted a couple of days before the return of the rain, but I remember it well because the snow came down thick and fast and the main roads were closed resulting in a 3 hour journey home from work (usually 20 minutes). We ended up with the most snow I've recorded in one single fall since moving here in 2003 - probably because the wind came more from the south, as we tend to be sheltered from northerly and easterly events here. Although we had more lying snow in 2010, it accumulated from several falls and not in one go.

A relatively recent example which delivered heavy snow for us here in Wales (albeit short-lived):

Try http://www.nc-climate.ncsu.edu/climate/patterns/NAO.html Scroll down to "positional effects" - there are some nice charts with examples of how the height anomalies are further east or west based for -NAO.

Excellent - thanks Bryan. If I'm way out with this comparison, at least I can be more accurate in future

The current synoptic set-up for our part of the world doesn't seem too far away from mid-January 1965: Fast forward to 48 hours out and still fairly similar, but you can see that the base of the trough is allowed to progress further east in 1965: 96 hours out, and you can see how the 1965 evolution allows the cut-off low to sink south, bringing an easterly flow. The difference here is that the trough over the UK is allowed to sink further SE in 1965, linking up with the lower pressure over southern Europe, while in the current GFS modelling shown this doesn't occur. An additional caveat is that the 1965 pattern wasn't particularly remarkable as far as I'm aware (Jan '65 CET 3.3, Feb 3.1) but the change in pattern does allow the lows to track south and the blocking from the east to back west over and to the north of the UK, which is similar to what some have suggested as a possible evolution in the longer term this month. So this could be an example of how such an evolution may be able to play out if the current pattern persists, probably not this time around as those who have studied the 500mb charts have suggested, but there may be further opportunities as the set-up seems to continue for a while to come, e.g.: Unfortunately I can't seem to find northern hemisphere archive charts so I can't see how similar the overall pattern is - which is likely to be driving developments here.

Refreshing change having to dust off the ice scraper again after last year... long may it continue!

Interesting stuff - of those winters, we get CET figures of 1.9, 1.6. 0.9 for 1916/7, 3.4, 1.3, 0.4 for 1928/9, 3.1, 2.2, -1.9 for 1946/7 and (perhaps the odd one out) 5.5, 4.5, 5.4 for 1966/7. The first three also all follow a descending pattern from moderate cold into severe cold as the season progresses. Would this be part of the reason you revised your winter forecast CET downwards Roger? Of these, 1928 seems to be a good match for our part of the world at this point.

4.4C for me please (and not just because the previous two entries have been 4.6 and 4.5... honest!)

Just to add my thanks for the forecast, as always very well explained and clearly a lot of work has gone into it. I like the prospect of a 'cold hearted' winter with the core of any cold spell falling in late December / early January - in my opinion the best time to experience cold weather to make it very seasonal - so am hoping the forecast is a success!

Yes, beautiful day today, let's hope it's the first of many... Worth remembering the start of December was fairly settled even last year - here, the first 10 days were completely dry. The real horror-fest didn't get going until around 15th. Not that I'm suggesting we're likely to get a repeat, but it's strange to think that last Christmas we were only really into day 10 of the wet and windy weather that would give us such a dire winter.

We did well here in Jan 2013 too, and what was particularly good about that spell was that the amount of snow we received was quite unexpected - had expected a dusting on 23rd but the snow carried on falling for a lot longer than forecast: http://www.bbc.co.uk/news/uk-wales-21169886! We had more in Jan & Dec '10, but generally the forecasts then were fairly accurate so it was less of a surprise. It was also our last snowfall, so hoping for more this year. If not, cold, crisp and sunny will do for me and be an infinite improvement on last winter.

The 2005 event was the best I've experienced, affecting parts much further east than usual. Here in Carmarthenshire we had the deepest snowfall I'd seen since at least 1996, possibly longer (although we've since had more in Feb '07, Jan '10, Dec '10 and Jan '13, so that may just illustrate how poor the 1997 - 2004 period was for snow here). http://news.bbc.co.uk/1/hi/wales/4470188.stm http://news.bbc.co.uk/1/hi/wales/4468222.stm Some good analysis here: http://www.geologywales.co.uk/storms/autumn05b.htm J10's earlier post also reminded me of the 2001 event which delivered some decent snowfall on Boxing Day for us: We also had a dusting on Christmas Day 2004. For Christmas Day snowfall though 1993 was the best I can remember, although looking at the charts I'm not convinced it was a northerly streamer set-up:

Worth taking a look at Roger's posts at the start of each CET month thread, if you haven't already, which have details of the all-time high and low records as well as some of the recent figures and longer term averages for both recent and historical periods. I always have a good look before posting an entry in the competition (not that it helps with my accuracy!) and if you just want to get a flavour of how the month may pan out, they are a very useful guide.

Good point. Here's their forecast for last winter: http://www.accuweather.com/en/weather-news/europe-winter-forecast-warmer/19131940 "Even with a projected stormier end to the winter, rain and snow should be no more than average for the British Isles" Not completely out, but certainly no forecast of the excessive rain and wind that we actually experienced: just a wet end to the season. It doesn't seem as if it would take a great deal of tweaking for their 2014-15 forecast to play out better than suggested for cold in the UK - note the reference to southerly and not SW'ly winds, possibly suggesting a block to the E, and the reference to wet weather over Spain and S Europe, suggesting low pressure there. If the pattern shifts further west, we could end up with a more favourable pattern for cold which would also fit in with some of the signals currently suggested by others (negative AO, Scandi blocking etc.). Of course, it could also be that we'll end up the wrong side of any blocking for cold, but certainly all to play for at this stage.

6.4C for me please

A few pics of Cbs building up and moving away yesterday evening - apologies for poor quality, they were taken on my phone.

Thunderstorm here - 4th day thunder heard in the last 6 days making this the most thundery month of the year so far.

As others in Wales have already mentioned, exceptional night here last night. Thunder heard frequently from 5pm until 7am, and again at 10am, with at least 8 separate cells with frequent lightning. It's fairly common to get the odd steric here in an Autumn / Winter cyclonic SW flow, but for practically every cell to give lightning is exceptional. The closest comparison I can think of is Nov '09, but even then we only had a maximum of around 3 storms / thundery showers in one night.

With you on the Bartlett, but I'd take a mid-Atlantic high....

Thanks J10. Not done so well this year until now, so good to get a direct hit!