Will 2009/2010 Be An Historic Winter?

[damianslaw]

Last post to this particular thread from me. Reiterating my previous posts, the most severe and snowy conditions this winter in the Lake District were bottled up in the period 17th dec- 15th Jan. Thereafter we saw very little snow any nothing exceptionally severe temperature wise just persistantly cold. Take away the 4 week period above it would score as preety average in my books, however, the pre christmas period between the 17th and 25th dec was special for its heavy snow and the period 3rd-9th Jan for 144 hours of not getting above zero.

We were very close to recording a historically very severe winter, however, apart from the Highlands for the majority the synoptics just didn't quite play ball.

Still overall this winter has been a cracker for cold frosty sunny dry weather, most weekends being excellent for walking the fells, it was a like someone changed the switch in mid december after the abysmal November - what a contrast. The rivers are now fairly low and if it had not been for the heavy rains in November, the depth of cold in the ground would have been far greater establishing itself much more quickly.

[coram]

In terms of consistently cold weather this has most definately been an historic winter, perhaps the most historic of all. Even the winters of 62/63, 46/47 and 78/79 were not as consistently cold for as long. It is remarkable the number of 'normal' people (i.e. those not afflicted by weather OCD) who are commenting on the fact that the cold weather started in November and shows no sign of ending. They are factually wrong in so much as, at least in England and Wales, the cold weather did not start until 11th December and is now showing signs of relenting, however they are correct in that there has been virtually no mild weather for months.

If the measure of an historic winter is the number of bouts of very severe weather, then I think that this winter has fallen just short in England and Wales. Different areas of the country have had severe cold and/or heavy snow at different times, but, at least in the south, I feel we were just one episode short of historic. If the heavy snow and very cold temperatures of the pre Christmas and post New Year periods had been replicated in February, then I think we would have qualified.

It is a different story of course in Scotland. Their winter was a whisker away from being the coldest since 1914, with only 62/63 being colder by 0.08C. Similarly, Northern Ireland had their coldest winter since 62/63. Scotland's winter qualifies as historic on all counts - severe cold, heavy snow, lying snow and the consistency of the cold. As an aside, I was very surprised to see that the coldest winter of all in England and Wales (62/63) was quite significantly colder than the coldest in Scotland.

This winter has been historic in another sense. Many people, me included, believed that we would never again have a significantly cold winter. It just seemed that, although the rise in temperature over the last couple of decades has been relatively small, it meant that the chance of a really cold winter had gone. This winter is historic in that it proves beyond doubt that we can have very cold winters and that we will have them in the future.

[kold weather]

Last post to this particular thread from me. Reiterating my previous posts, the most severe and snowy conditions this winter in the Lake District were bottled up in the period 17th dec- 15th Jan. Thereafter we saw very little snow any nothing exceptionally severe temperature wise just persistantly cold. Take away the 4 week period above it would score as preety average in my books, however, the pre christmas period between the 17th and 25th dec was special for its heavy snow and the period 3rd-9th Jan for 144 hours of not getting above zero.

To be honest though for most winters thats the case. For example 86-87 wouldn't have been that impressive were it not for the big easterly plunge in jan. 85-86 wouldn't been that impressive had it not been for that very cold Feb. 81-82 wouldn't have been all that impressive had it not been betweensay 10th december to the 15th of Jan. 68-69 wouldn't have been at all great without a pretty impressive Feb. 90-91 would have been only an ok winter were it not for its big easterly plunge in Feb, and indeed the background cold for the first half of the month in general.

Only the truely severe winters can claim to have very long lasting severe set-up...and England and Wales probably fell just short of that as you say.

[Thundery wintry showers]

I think this is where the "snowiness" classification that I devised has its flaws if used as an indicator for overall winter severity. 17 Dec to 15 Jan contained a number of widespread, non-marginal snow events which stuck around on the ground for long periods, and in parts of Scotland the period was cold and snowy throughout with no significant interruptions. But from 15 Jan to 1 March we had frequent snow across the country but most of it was marginal and didn't stick around for long.

In contrast many areas of the country had persistent snow cover in 1947 (23rd Jan into mid Mar) and 1963 (26th Dec into late Feb/early Mar) because it was cold enough to sustain a snowpack in between snow events.

But did 1979 surpass this winter in terms of duration of severe cold? A large majority of the snow events of that winter quarter were crammed into the period 31 December-16 February, so just over a fortnight longer than the big wintry spell of 17 Dec-15 Jan 2009. But then again, the first half of Feb 1979 was quite mild at times in the south, and in Lancaster there was very little snow at all, so in certain areas of the country people could've argued that in their own back yards, severe snowy weather only lasted from 31 December to 29 January. I think the main thing that elevates 1979 above this winter is the more even geographical distribution of snow and the cold snowy spring that followed.

And of course in 1947 and 1963, some parts of north-western Britain had almost no snow at all.

[AderynCoch]

The provisional 11th December - 10th March CET is in at... 2.002C!

I think I miscalculated it slightly first time round (I was expecting something like 1.99C), but I would guess that March's figures will be downgraded slightly come April given that Manley is currently running a bit behind.

[damianslaw]

I think this is where the "snowiness" classification that I devised has its flaws if used as an indicator for overall winter severity. 17 Dec to 15 Jan contained a number of widespread, non-marginal snow events which stuck around on the ground for long periods, and in parts of Scotland the period was cold and snowy throughout with no significant interruptions. But from 15 Jan to 1 March we had frequent snow across the country but most of it was marginal and didn't stick around for long.

In contrast many areas of the country had persistent snow cover in 1947 (23rd Jan into mid Mar) and 1963 (26th Dec into late Feb/early Mar) because it was cold enough to sustain a snowpack in between snow events.

But did 1979 surpass this winter in terms of duration of severe cold? A large majority of the snow events of that winter quarter were crammed into the period 31 December-16 February, so just over a fortnight longer than the big wintry spell of 17 Dec-15 Jan 2009. But then again, the first half of Feb 1979 was quite mild at times in the south, and in Lancaster there was very little snow at all, so in certain areas of the country people could've argued that in their own back yards, severe snowy weather only lasted from 31 December to 29 January. I think the main thing that elevates 1979 above this winter is the more even geographical distribution of snow and the cold snowy spring that followed.

And of course in 1947 and 1963, some parts of north-western Britain had almost no snow at all.

Winter 78/79 saw generally more severe conditions in terms of heavy snow and strong winds, however, as you say it didn't see such persistant cold as this winter. A big difference with this year and 78/79 is how severe wintry onditions persisted well into March, the first half being very cold and snowy. Though the cold has persisted into March this year similiar to 1986 in many respects we have lost wintry severe conditions in terms of snow, though we have had very cold nights.

[Weather-history]

11th Dec 2009 - 10th Mar 2010: 2.0

The number of occasions that a daily CET mean of 7.0 or greater in that period was recorded? 0

Here is how this period compares to previous such periods up to 1772 which were colder than this. 1772 is when daily CET mean records begin and the number of occasions in that period that a daily CET mean of 7.0 was recorded.

11th Dec 1978 - 10th Mar 1979: 7

11th Dec 1962 - 10th Mar 1963: 5

11th Dec 1946 - 10th Mar 1947: 2

11th Dec 1941 - 10th Mar 1942: 9

11th Dec 1939 - 10th Mar 1940: 8

11th Dec 1928 - 10th Mar 1929: 7

11th Dec 1916 - 10th Mar 1917: 5

11th Dec 1894 - 10th Mar 1895: 9

11th Dec 1890 - 10th Mar 1891: 6

11th Dec 1880 - 10th Mar 1881: 10

11th Dec 1878 - 10th Mar 1879: 10

11th Dec 1854 - 10th Mar 1855: 15

11th Dec 1846 - 10th Mar 1847: 6

11th Dec 1844 - 10th Mar 1845: 3

11th Dec 1840 - 10th Mar 1841: 8

11th Dec 1837 - 10th Mar 1838: 14

11th Dec 1829 - 10th Mar 1830: 9

11th Dec 1822 - 10th Mar 1823: 2

11th Dec 1819 - 10th Mar 1820: 9

11th Dec 1813 - 10th Mar 1814: 5

11th Dec 1799 - 10th Mar 1800: 2

11th Dec 1798 - 10th Mar 1799: 9

11th Dec 1794 - 10th Mar 1795: 3

11th Dec 1784 - 10th Mar 1785: 6

11th Dec 1783 - 10th Mar 1784: 7

11th Dec 1779 - 10th Mar 1780: 11

11th Dec 1775 - 10th Mar 1776: 5

Shows how highly unusual the lack of mildness has been within that period.

Edited March 11, 2010 by Mr_Data

[TonyH]

Just put this in the Today's weather thread but it's relevant here as an adjunct to this Winter, as the effects are now becoming apparent especially with this exceptionally frosty, sunny and dry start to March. Most nights frosty so far, 3 of them around -7c, fantastically sunny this week on the whole:

Countryside is tinder dry in west Wales, saw several grass fires on the hills today. The fields and hills are yellowish brown- dead from the long cold winter, and this amazing March of no rain, prolonged sunshine and severe frosts.

Hedges and banks have been stripped of their undergrowth so that its weird to see through them, while the undergrowth and bracken in woodlands is either dead and flattened, or desiccated and crumbling. The bracken, leaves and twigs just crumble or snap in the hand.

The ground still has a leaf cover as it would in December, many of the leaves preserved by the lack of rain and constant cold.

Still very few Daffodils, but Crocuses and Snowdrops largely remain in full bloom, they are usually dead by now. Hedgerows show no sign of leafing nor providing cover for nesting birds.

All in all a most unusual situation to be in for early Spring!

I am wondering just how far back do we go to beat this early March in terms of sustained low minima and hard frosts, which have been mostly in Wales and the west? 1940's at least?

[Thundery wintry showers]

The average minimum for 1-10 March 1970 was -2.95C in the CET zone- this is the benchmark figure for 1-10 March 2010 to beat, I think.

Edit: looks like 1970 remains unbeaten for its low minima, Hadley has it at -1.6 to the 11th, and Manley is unlikely to be over 1.3C lower.

Edited March 11, 2010 by Thundery wintry showers

[TonyH]

Thanks i do recollect 1970 i think the snow lay for much of the first week.

Mean minima here -3.5c 1-12th.

[Rich44]

I think it's going to go down as a special winter I can remember the last time I enjoyed snow that covered the ground non-stop for 2 weeks I was 13 so a long time ago, not talking about the entire UK just where I lived at the time, sure we had snowy winters but 2 weeks of good solid cover, no.

We've had lakes frozen solid round here for a month, Holt country park was frozen up so thick you could walk across it (I did verrrrry carefully) even after the snow was long gone it was still frozen solid truly amazing.

The best part is it's the first "real" winter my little boy will remember (3) his brother is still too young to remember this one probably (18 months) so here's to more like this, maybe it's a trend in our winters, only a 8 months to go to find out

[Norrance]

For me here it was historic in that there were thirty consecutive snow lying days equalling 1986 and the temperatures over the three months equalled [just beat]1979. This was mostly due to the very cold December though. However the second half of the Winter though cold was pretty snow free and overall there was no one severe snowfall.

Up in the Highlands though it was more historic with several severe snowfalls with some areas breaking 80 snow lying days.

My mums home on lower ground in Highland Perthshire has had 60 snow lying days up to and including today, beating 1981/82's 56 and the most since 1979's 70. A lot of snow has melted over this weekend though.

[Thundery wintry showers]

Flicking through the past synoptic charts, I know we've had past analogues come up before (most notably 1965/66), but no-one has mentioned the winter of 1959/60, which contained cold spells with remarkably similar synoptics. The winter was merely close to average overall for temperatures and snow events because these cold spells didn't arise until much later in the season and were counterbalanced by mild spells- my guess is that the lack of a strong negative Arctic Oscillation during the 1959/60 season made it harder to sustain cold synoptics and prevent the mild south-westerlies from flooding in at the close of each cold spell.

During January 1960 a spell of cold weather evolved in an uncannily similar way to December 2009 and also had a lot in common with the synoptic evolution in February 2010 which very nearly produced a significant easterly in the second week.

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600107.gif

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600110.gif

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600113.gif

So far, a build-up similar to Dec 2009:

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600114.gif

...and a north-easterly blast similar to the 17th/18th December 2009- same airmass source, similar potency

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600116.gif

Northerlies come streaming in, associated with marginal frontal events (rain for west, snow for east)

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600118.gif

West based negative NAO setting up.

Unlike in the 2009/10 season the northern blocking soon collapsed- allowing mild SW'lys in from the 23rd January to the end of the month.

February 1960 also had some similar synoptics during its fortnight of cold snowy weather in the middle. The first cold blast wasn't all that synoptically similar to 2009/10 but did have some common features- the northerly source and the resulting NE'ly vector with LP to the S, similar to early January 2010 in those respects.

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600210.gif

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600212.gif

But then, after the first blast (a NE'ly over the UK with low pressure drifting slowly E to our south) came the classic west-based negative NAO with a NW flow and LP west of Scandinavia, a common feature of late Dec 2009 and late Feb 2010:

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600216.gif

And then, a classic west based negative NAO setting up even further west, giving the familiar pattern of sunshine and snow showers in the north, rain in the south and marginal frontal events in between:

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600219.gif

http://www.wetterzentrale.de/archive/ra/1960/Rrea00119600222.gif

Once again, though, February 1960 was not especially cold because the negative NAO situation soon collapsed thereafter heralding exceptionally mild weather by the 28th/29th, and it had also been very mild in the first week.

So, while we can certainly argue that Winter 2009/10 was very close to being one of the coldest and snowiest on record in central & southern England (while achieving this distinction in many parts of Scotland and some parts of N Ireland & N England), it can also be looked at the other way: we were also very close to having a statistically unremarkable winter like 1959/60.

[Weather-history]

One little quirk of stats, each winter month has been colder than its predecessor for the CET since the mild peak of winter 2006-07

Dec 2006: 6.5

Dec 2007: 4.9

Dec 2008: 3.5

Dec 2009: 3.1

Jan 2007: 7.0

Jan 2008: 6.6

Jan 2009: 3.0

Jan 2010: 1.4

Feb 2007: 5.8

Feb 2008: 5.4

Feb 2009: 4.1

Feb 2010: 2.8

[summer blizzard]

How about the other seasons??

[Cheese Rice]

Last winter like many others was characterised by marginal snowfalls, granted it wasn't marginal here, but only due to elevation. On low ground Leeds 90% of snowfalls were all marginal so it isn't really the idea of a "historic winter", ideally most snow events shouldn't be marginal which wasn't the case. However most of the "historic" falls of snow in America have all been marginal so I suppose it is what falls out of the sky that counts not the temperature at the time.

Edited March 27, 2010 by 10123

[Optimus Prime]

For Northern Scotland it was the coldest winter on record. So there it was historic, elsewhere? No.

Glad that's cleared that up.

[LomondSnowstorm]

For Northern Scotland it was the coldest winter on record. So there it was historic, elsewhere? No.

Glad that's cleared that up.

So 78/79 wasn't historic?

[Optimus Prime]

78/79 was far from historic.

[Cheese Rice]

For Northern Scotland it was the coldest winter on record. So there it was historic, elsewhere? No.

Glad that's cleared that up.

Well Northern England (Leeds) had comparable snowfall and temperatures, the CET doesn't really tell the full story as it covers a relatively small area.