virtualsphere

3.9C for me please.

Well technically there are 12 days of Christmas so why not... are your decorations still up? Funnily enough I had a storm overnight - three claps between 5 and 6am and saw one bright lightning flash. Only the second thunder I've heard this year. Hope your dog is OK - mine used to hide before a storm hit and I could never work out how he knew unless he could sense something in the atmosphere (or maybe he had a secret NW extra subscription).

Nice video! Sounds like Boxing Day is more active where you are. Here's the fax chart for 1999, not aware of anything here that day but sounds like it was quite active: Here's yesterday - I guess the trough over the SE was probably responsible for the storms there: And here's 2009 which I mentioned above, they are all quite similar in terms of the positioning of the low and the general flow coming from the north, swinging round across the Atlantic west of Ireland and then approaching the UK from the SW. The 2009 chart is for 26th, as the thunder here was in the evening so the 00z chart is closer to the synoptics at the time. All have a fairly similar rPM set-up with the flow originating from the north, and swinging around in the Atlantic west of Ireland before approaching the UK from the SW. Fax chart archive courtesy of Wetterzentrale at http://www.wetterzentrale.de/topkarten/tkfaxbraar.htm

Nice to see some folks have heard thunder today. As we've been unable to enjoy a white Christmas this year at least a few posters have had a chance to experience some convective weather instead. I thought it might be interesting to start a thread to see who has heard thunder or seen a storm at Christmas in the past. At this time of year, I'd guess it is mainly those near to the coast. Here in SW Wales, I've heard thunder twice on Christmas Day - 1997 and 2009, both in a RPm set-up in a SW flow. In 1997, I was awoken in the early hours by a huge crash of thunder. There was only the one, and I heard no more throughout the day. 2009 was more eventful and isolated to our area. During the cold spell, milder air tried to push in from the SW on Christmas Day which started very cold and frosty, with sheet ice on the pavements and roads making the driving very treacherous. Later in the afternoon, the temperature rose and the ice melted, and by the time we left my wife's family to drive home heavy showers had started to push in, and it was raining steadily. Shortly after arriving home at 6:40pm, there was a huge crash which knocked out the power, and this was followed by several more accompanied by torrential rain. The storm was short lived and we settled down in front of the TV, but it wasn't long before a second thundery shower pushed in with a couple of close strikes which tripped the switch again. Fortunately the milder weather was shortlived and we went on to experience some classic winter weather in late December 2009 and January 2010. Apologies if this should be in the historic weather thread but thought it would be of more interest in here. Merry Christmas to everyone

Better hang on to those polystyrene flakes left in the box after the gifts are wrapped if you want a white Christmas this year

That would be a good summary for here as well. When it hasn't been mediocre, it has just been nondescript and dull. Not a flake of snow all year, and despite the continuous rain we have had the least amount of thunder in at least 5 years. It wouldn't be too much of an exaggeration to say I could count the number of dry sunny days on my hands. The rain has also coincided with the dates I'd have wanted to be dry. The only saving grace has been the dry, warm spell towards the end of May - superb and just a shame it didn't last longer. Great weather here for the Olympic torch relay and the one decent day trip outdoors this year. We were spoiled here in 2010 for both sunshine and snow, and perhaps that has raised my expectations too much!

Good advice from Tony, I started measuring the rain in April and it does at least add some interest to the miserable weather (although I'm starting to wonder whether I'm causing the rain doing this as it feels like it hasn't stopped raining since I started measuring it!) At least then when you feel like moaning you've also got some stats to back it up! Edit: that sounds a little harsh, I wasn't having a go at anyone as I was moaning myself yesterday.

Jan 1969 had a similar setup with -NAO that didn't deliver cold to the UK, whereas Feb 1969 produced a notable cold spell. If the evolution proves similar (and it may not) then we might just need to be patient...

Early in the year did feel dry and Jackone's stats confirm this. I don't normally mind a bit of rain either but the continued absence of any long lasting dry, sunny weather is what I have found frustrating. As I mentioned before, it is really a timing issue for me... if the year's rainfall overall was identical but the dry spell was between June and September then it would probably be a different story! I've also been lucky not to have experienced any flooding issues and I hope for those affected the next few days don't cause too many problems especially just before the festive period. Have to agree a mild, wet Christmas is probably the least festive weather, but we've been spoiled in recent times and although last year was mild, we're probably still overdue a wet and windy zonal Christmas. Hopefully we can avoid one again this year! Certainly 2008 - 2010 increased my expectations of seasonal Christmas weather and last year came as a disappointment.

Absolutely, this has felt like a very wet year here, especially the dire summer. Autumn was probably more akin to average but still felt wet after such a lengthy wait for any dry spell. To be fair though it has probably felt worse to me because all of the days I really wanted to be dry were a complete washout (I'm sure I posted somewhere else the wettest day here this year was the August bank holiday Monday and that still stands). Hopefully the block will push back the Atlantic at some point and deliver at least some dry and cold weather even if we don't get snow!

Could be some fairly hefty showers over parts of S & W Wales tonight and into tomorrow. Some pretty bright colours on the Met Office rainfall animations. Pretty decent CAPE values for the time of year too. No sferics showing as yet on ATD but wouldn't be surprised to see some later especially round coastal regions.

Yes, looks like a potentially active few days coming up for us western coastal folks with some heavy showers and hail and thunder a possibility starting tomorrow evening and through into the weekend. NMM brings the negative LI figures quite far inland along the south coast as well come Saturday. Something to keep an eye on!

Even though this week's cold spell has been disappointing from a snow perspective given some of the model output earlier this month, I have enjoyed the weather over the last few days. It's been great to have another break from what has seemed like relentless rain since June, with just the odd dry week here and there, and a pity it's not going to last much longer. We've also had some respectable cold here - nothing on the scale of 2010 of course, but it's worth remembering that was the coldest for 100 years and snow cover helped to keep the temperatures down back then. Until this afternoon, the frost in the shade here hadn't melted for 2 days and it has felt seasonal - certainly the coldest spell of weather for some time here. Onto the next batch of wet weather and the NMM suggests cloud tomorrow followed by the rain currently progged to hit the Pembrokeshire coast at around 5am on Friday morning. No real sign of any change to this new pattern on the models at the moment with low pressure forecast to be west of the UK bringing generally SW winds and unsettled weather for the foreseeable. Hopefully we'll see the signs of some changes soon in the output just in time for Christmas Day... Just seen your post above Soupsurfer, too far out to be certain of the weather on Jan 12th, but according to the experts the teleconnections do support a colder theme in January but possibly not until later on in the month...

No snow so far this year, or in winter 2011/12. Maybe we're paying for all the snow we had the previous two winters!

Last Thursday (22nd November) my son was born at 11:45am in Carmarthen and later in the afternoon there was a thunderstorm ahead of the cold front which produced a couple of loud bangs which were audible from the hospital room. Unfortunately, although I could make out the flashes, I couldn't see much due to the frosted glass in the room and with my mind on other (my wife would say, more important) things I wasn't really in a position to be checking out the radar or sferics! Yesterday we had a phone call from a family friend who my wife had left a message with a few days ago about the birth. She apologised for not replying sooner - it turns out she had only just received our message because the lightning strike I'd seen from the hospital had struck her house and incinerated her telephone line. According to her report, a ball of lightning entered her neighbour's adjoining house through a window which was slightly open, which caused all of the electrical equipment in the property to buzz. The telephone line and power cables were pretty much destroyed and most of the electrical equipment was ruined including her husband's computer which was on the Internet at the time and "turned to ash" (not sure how much exaggeration there is here). The fire brigade were called and said that the occupants were lucky to be alive. Anyway, this is probably a long shot but I'm wondering if anyone happens to have any radar grabs / sferics plots for that day? The time would have been sometime between 1 and 3.30pm, hospital postcode SA31 2AF. It would be interesting to see what happened and save them for posterity so I can show my son one day!

Apologies if this is off-topic, but in reply I had a quick look at 1968-9 in this post. It wasn't specifically related to the stratosphere which is why I posted it in the general winter thread but it has probably got a bit buried now.

3.5C for me please :-)

Very wet here north of Llanelli but I only started keeping records this year so have nothing to compare it to. Over 100mm every month since April with over 200mm in June and August. On purely instinct I would say it is probably the wettest year since I moved here in 2003 but 2008 may have come close.

Christmas Day 1993 was a good one here. It's the only occasion where I've been able to build a snowman on the day - tried in 1995 but didn't have enough snow, and in 2010 we already had a snowman which my son had built a few weeks before! My favourite unexpected snowfall was probably either of these which I posted about recently in another thread: Both fairly localised - the first was forecast as a rain event and gave me the most snow I've experienced in a 24 hour period from very marginal upper air. The second was forecast but I was only expecting a dusting and ended up with a dumping from a fairly continuous train of snow showers.

Good call there Paul. We've already had 50mm rain here since the weekend, and with the high water levels those 48 hour totals look a little worrying. Not much out of the ordinary for around here but the last 6 months have been exceptionally wet. My wife is overdue to give birth - not looking forward to driving to the hospital in that!

As your forecast method produces a trend using a series, when you have the final November CET could you add this to your dataset to generate predictions for Dec, Jan & Feb based on the trend?

Thanks - as bluearmy mentions these are just measures of pressure patterns, you can view a forecast graph at http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml / http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml but I believe these are just based on model output and so will change as the model run data changes (hopefully someone more knowledgeable will correct me if I'm wrong). As we get nearer winter, probably best to look for a negative value in the AO & NAO if you're after cold but as 1991 shows it's not absolutely essential - definitely want to avoid strong positives though in both indices (look at early 1989 and early 1990!).

To try and learn more about how the NAO (North Atlantic Oscillation) and Arctic Oscillation (AO) affect our winters, I have superimposed the historical NAO data graph onto the AO graph. I'm sure someone will have tried this before, but I've never seen it Here is the result. You'll see the AO data in the usual red / blue colours, with red for positive and blue for negative. On top of this you'll see the NAO data with positive in light blue and negative in yellow. Where both AO and NAO overlap, they show as black. I've added some arrows for classic UK winters. There does seem to be a theme here - 1963, 1979, 1981, Jan 2010 and Nov/Dec 2010 all display a very similar pattern: both NAO and AO negative (black) with many of these showing some yellow negative NAO beneath the AO. These aren't necessarily the deepest negatives on the graphs, which would suggest the depth of negativity doesn't matter a great detail for cold in the UK. There are some exceptions to this pattern - February 1986 is an interesting example with positive NAO but negative AO. 1991 is an even greater anomaly with with both NAO & AO positive: NAO more so. 1969, which I looked at in more detail last week in this post, is a good example of a very negative NAO and AO giving very contrasting months, producing a decent wintry month in the February but a mild one in the January. This shows that if the blocking sets up in the wrong place then cold won't necessarily follow. Another period which shows the 'right' AO & NAO pattern but didn't deliver significant UK cold is 2002/3. One tentative conclusion I would draw from this is that getting a negative AO is probably more crucial for cold than NAO: I couldn't see any red spikes in the classic winter months mentioned. Some excellent info here for those wanting to know more about the AO and NAO: http://www.nc-climat...tterns/NAO.html

Certainly a downward trend in the upper air temperature if GFS is to be believed up until around 25th (although this week has felt chilly without the sun coming through) but not quite cold enough for snow potential yet unless one of the outliers comes off. A lot of scatter after this which is to be expected in that timeframe but also reflects the wide range of options on offer as discussed in the Model thread. Potential encouragement for cold fans is the number of ensemble members going for upper air of -5C or below in the longer term although there are also some mild members in there too and large discrepancies between the 12Z and 18Z generally by T+180 - so all to play for at the moment. Dry, cold and frosty would do for me after all the rain we've been having lately - still plenty of time for snow in Dec, Jan, Feb...

Statistically, and without taking into account the forecasts, models or background signals, a repeat of November - December 2010 would be very unusual as that December alone was the coldest for around 100 years. Generally it's more likely to have cold weather of that severity in January - February: e.g. while December 2010 was the coldest December in a century, you only have to go back to 1986 to find a colder month (February), and there were three more sub-zero Februaries 1963, 1956 and 1947 in the 20th Century. Although we've had reasonably cold Februaries in the last few years, it is the one winter month in which there was a colder example in the 1990s than the 2008 - 2011 period (1991). On the other side of the coin, however, remember the warm April in 2007. Statistically the chance of that type of event recurring at the same time of year must have been just as remote - and then along came April 2011. The weather doesn't always play ball! It seems there has been a recent tendency for winter weather to come earlier over the last few years with colder Decembers, and also spring to come earlier, with warmer Marches and Aprils, and sadly for autumnal weather to come earlier too - spoiling our summers! Maybe it just feels like that...