Category Archives: Christmas Day weather

Christmas 1810: stormy then very cold

Earthquakes in Italy and early season snow cover in Siberia have been well documented in 2016.

They were also mentioned by Luke Howard in his publication The Climate of London in 1810.

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He also mentions winter thunderstorms over the Yuletide period, from Christmas Eve to Boxing Day – the amount of rain overflowing the Thames.

24th: Very windy night with heavy rain. 25th: Wind high all day with rain frequent lightning in the evening from SE. 26th: Wind very boisterous early in the morning day fine the rain of the last three or four days being impeded in its passage to the Thames by the spring tides overflowed the banks and filled the marshes.

Within two days of this wild and wet spell, complete with strong north-westerlies, the wind swung north and then north-easterly to usher in 1811 with a 12-day cold spell.

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The conditions of the cold spell were not severe, the coldest night was -8C, it was a pretty standard cold spell for the time and one that the south-east used to experience with fair regularity in the early to mid 1980s.

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Models currently show a (fairly) narrow chance of a stormy Christmas period. It would be interesting if it were followed with a cold spell in January – just like the ones we used to get in 1980s.

* The Booty website also contains the following on that notable month…
What is thought to be Britain’s strongest tornado occurred in December 1810. A category of “T8” (on a ten-point scale) occurred on the 14th at Old Portsmouth. The TORRO website says it:  “tracked from Old Portsmouth to Southsea Common causing immense damage – although no deaths, it is believed. Some houses completely levelled and many others were so badly damaged that they had to be demolished; chimneys were blown down and the lead on a bank roof was ‘rolled up like a piece of canvas and blown from its situation’.”

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All bets off for white or green Christmas

Weather models are now in range of predicting the weather on Christmas Day and the all important question of ‘Will it be a white one?’

xmas-morning
High pressure centred over the near continent leaves the UK in a feed of very mild air from the Azores

The operational output from the GFS model today answers that question with a resounding ‘no’. A huge anticyclone centred over the continent puts the UK in a very mild SWly feed, the air source from the Azores. You would expect temperatures in London to top around 12C after an overnight low of around 5C.

The Daily Star this morning was even more bullish with it’s splash proclaiming that punters had poured money into Yuletide being exceptionally mild, predicting 15C which would give last year’s record warm period a run for its money. But they have based this forecast on one operational outcome on one model!

Anyone who follows weather forecasts knows that there’s always huge uncertainty in outcomes beyond five days. So putting faith in this forecast 16 days before the event could be dismissed as plain stupid. A closer look at the ensembles – model solutions that pick out trends of several operational runs – suggest that there is very wide spread in outcomes for the weather for Christmas Day: either very cold or very mild! And the GFS system is also hampered by lack of vertical resolution in the stratosphere.

star
Punters are apparently piling money into it Xmas day being 15C – but ensemble forecasts at this range show outcomes from very mild to very cold.

Taking a broader view of what happens in real life over the last few years there always seems to be a pivotal moment around December 17th. The odds always have to favour the mild weather for us though.

Earlier this month in my November review I found that there was a 55% chance of a cold spell at the end of December. My guess at this range is that the run up to Christmas will see us under the influence of high pressure centred over the near continent – a ‘phantom’ cold spell that is cold at the surface but, at 850mb (5,000ft), well above freezing. Christmas day in London will start frosty with the temperature topping out at 5C or 6C. Any proper cold spell with snow will not bite until 29th.

That’s my guess. My advice to anyone who fancies a flutter is to hold on to your money until the 17th. Or place a bet on both.

* The definition of a white Christmas used most widely – notably by the bookies – is for a single snowflake, even if it lands in the midst of heavy rain, to be observed falling in the 24 hours of 25 December at a specified location recognised by the Met Office.

** On average, snow or sleet falls in the UK 5 days in December, compared with 7.6 days in January, 6.8 days in February and 6 days in March. White Christmases were more frequent in the 18th and 19th centuries, even more so before the change of calendar in 1752, which effectively brought Christmas back by 12 days. Climate change has also brought higher average temperatures over land and sea and this generally reduces the chances of a white Christmas.

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The GFS countdown to Christmas Day

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The op chart for Christmas Day on 24/12 shows the UK split between influence from a low to the north of Scotland and a European high giving a balmy SW’ly . Rain moves up from the SW during the day. Temps in London rising to 13C after a low of 4C. Best chance of anything wintry northern Scotland

The odds for snow on Christmas Day have been shortened for those that live in northern Scotland, reflecting the latest operational model runs that suggest the current mild regime will continue in the south.

 

The operational runs of the weather model GFS began to include Christmas Day in its forecast on December 9. Admittedly T+384 is la-la land in terms of trying to accurately predict what the weather will be like on the day but I thought it would be fun to see how the outcome changes over the next two weeks or so.

William Hill odds for snow on Christmas Day:
9th: London 5/1; Aberdeen 5/2; Edinburgh 3/1; Glasgow 3/1; Newcastle 4/1; Belfast 5/1;  Birmingham 6/1; Norwich Airport 7/1; Penzance 10/1
10th: unchanged. 11th: unchanged. 12th: unchanged. 13th: unchanged. 14th: unchanged. 15th: unchanged. 16th: London 8/1; Aberdeen 7/2; Edinburgh 4/1; Glasgow 4/1; Newcastle 5/1; Belfast 5/1;  Birmingham 7/1; Norwich Airport 10/1; Penzance 16/1.

22nd: London 12/1; Aberdeen 5/2; Edinburgh 7/2; Glasgow 7/4; Newcastle 5/1; Belfast 10/3;  Birmingham 10/1; Norwich Airport 10/1; Penzance 12/1.

23rd: London 18/1; Aberdeen 5/2; Edinburgh 7/2; Glasgow 7/4; Newcastle 5/1; Belfast 10/3;  Birmingham 10/1; Norwich Airport 10/1; Penzance 16/1.

My predicted outcome for London made at the beginning of December:  TMax: 7C  TMin: 1C Moderate westerly 60% chance of rain shower 1hr of sunshine

  • Please note that the outcome will change markedly from run to run, day to day. The best hint of what the weather will be like will be from T=240z (10 days) and, reliably, T+120z. If the pattern is zonal then detail can only start being pinned down at T+72z.|
xmas091206z
5C, variable winds with threat of rain approaching from south-west. Chance of wintry showers Liverpool northwards. Snow On Christmas Day 5/2 Aberdeen Airport 3/1 Edinburgh Airport 3/1 Glasgow Airport 4/1 Newcastle Airport 5/1 Belfast Int. Airport 5/1 Leeds Bradford Airport 5/1 Liverpool Airport 5/1 London Heathrow 6/1 Birmingham Airport 6/1 Dublin Airport 6/1 Manchester Airport 7/1 Bristol Airport 7/1 Cardiff Airport 7/1 Norwich Airport 10/1 Penzance RNAS Culdrose
xmas1012
The operational chart for Christmas Day on 10/12 shows ridging from the south allowing a brief spell of quiet weather. Temps in London a couple of degrees above freezing with frost at night. A flurry possible almost anywhere though east coast most likely.
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The op chart for Christmas Day on 11/12 shows a ridge bringing a brief spell of cold, quiet weather. Temps in London about 6C after a cold, possibly frosty start. Dry to start though increased risk of rain from the west later. Best chance for anything sleety probably Glasgow…
xmas1212
The op chart for Christmas Day on 12/12 shows the UK in a col. Rain a possibility almost anywhere but chiefly in the SW and south. Temps in London about 6C and a low of 3C. Best chance for anything wintry probably Aberdeen toward midnight…
xmas1312
The op chart for Christmas Day on 13/12 shows the UK in a returning N’ly regime. Heavy rain spreading in to SW and S. Temps in London about 12C and a low of 6C. Best chance for anything wintry in the far north
xmas1412
The op chart for Christmas Day on 14/12 shows the UK in a returning N’ly regime. Starting dry in the SE but rain spreading in later. Temps in London peaking at 13C after a low of 10C. Best chance for anything wintry in the far north
xmas1512
The op chart for Christmas Day on 15/12 shows the UK split between a returning N’ly regime and a large area of high pressure centred over Switzerland, advecting warm air from North Africa. Mostly dry across the UK with best chance of precipitation NW Scotland. Temps in London peaking at 10C after a low of 7C. No chance of anything wintry, anywhere
xmas1612
The op chart for Christmas Day on 16/12 shows the UK split between a returning N’ly regime and a large area of high pressure over central Europe, advecting warm air from North Africa. A band of rain lies across the UK though dry in the SE. Temps in London peaking at 13C after a low of 11C. No chance of anything wintry, anywhere
xmas1712
The op chart for Christmas Day on 17/12 shows most of the UK in a balmy SW’ly regime, controlled by a strong high pressure over central Europe. Air over the SE is all the way from the Sahara. Any precipitation confined to Scotland. Temps in London peaking at 11C after a low of 8C. No chance of anything wintry, anywhere
xmas1812
The op chart for Christmas Day on 18/12 shows the UK split between influence from a low centred over Iceland and a European high giving a balmy SW’ly . Air over the SE is from northern Spain. A band of rain heralds cooler air from the NW. Temps in London peaking at 11C and falling away during the day. Best chance of anything wintry Western Isles of Scotland
xmas1912
The op chart for Christmas Day on 19/12 shows the UK split between low centred off north of Scotland introducing a cooler NW’ly airstream while south just about hangs on to the European high. A band of rain clears SE early on 25th from the NW. Temps in London peaking at 10C and falling away during the day. Best chance of anything wintry high ground in N England and northern Scotland
xmas2012
The op chart for Christmas Day on 20/12 shows the UK split between influence from a low to the north of Scotland and and a European high giving a balmy SW’ly . Rain moves in from the west during the day. Temps in London rising to 12 after a low of 4C. Best chance of anything wintry northern Scotland
xmas2112
The op chart for Christmas Day on 21/12 shows the UK split between influence from a low to the north of Scotland and and a European high giving a balmy SW’ly . Rain moves in from the west during the day. Temps in London rising to 12 after a low of 4C. Best chance of anything wintry northern Scotland
xmas2212
The op chart for Christmas Day on 22/12 shows the UK split between influence from a low to the north of Scotland and a European high giving a balmy SW’ly . Rain moves up from the SW during the day. Temps in London rising to 13C after a low of 4C. Best chance of anything wintry northern Scotland
xmas2212
The op chart for Christmas Day on 22/12 shows the UK split between influence from a low to the north of Scotland and a European high giving a balmy SW’ly . Rain moves up from the SW during the day. Temps in London rising to 13C after a low of 4C. Best chance of anything wintry northern Scotland
xmas2312
The op chart for Christmas Day on 23/12 shows the UK split between influence from a low to the north of Scotland and a European high giving a balmy SW’ly . Rain moves up from the SW during the day. Temps in London rising to 13C after a low of 4C. Best chance of anything wintry northern Scotland

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Will Christmas Day 2015 be white in London?

Over the next two weeks speculation on Christmas Day weather will inevitably build. Will Christmas be white or green?

Shoulder of Mutton lake, Wanstead PArk

At this range it is impossible to tell from standard meteorological models though from the 15th, 10 days before the big day and when models can start to be relied upon for at least a general trend, the pieces of the weather jigsaw will start to fall into place.

Latest odds offered by bookies William Hill for a single snowflake at London Heathrow are currently 5-1, slightly shorter than I’d expect at this time of year. With the predominance of the European high I’d expect those odds to start to lengthen.

In terms of proper snow falling and settling, there has not been a white Christmas in Wanstead for over 30 years. In 2010, we could still see the Christmas card Victorian snow scene in small patches if our gardens, but these were leftovers of a previous dump, so it doesn’t count. There has been snow on several Boxing Days in Wanstead (1995 and 1996) and in the weeks running up to Christmas, but not on Christmas day itself. The most typical Wanstead Christmas day weather is mild and dry, although it has rained on 13 of the last 34 Christmas days.

Tree damage by the war memorial in Wanstead High Street by Scott Whitehead

In an earlier blog I had a look at what the last 170 or so Christmas Days in London were like weatherwise and found that snow actually falling on the day is extremely rare. Since 1840 there have been just 19 occasions of snow or sleet falling on the capital on Christmas Day which equates to a probability of just under 11%. If you consider that the last ‘white Christmas’ (see note) was in 1996,  then we are well overdue one.

But the weather doesn’t adhere to human created calendars and behave like it should on any given day. But patterns in any given year can sometimes repeat though correctly predicting they will happen is more down to luck. Nevertheless I’ve had another look at my calculations for this winter and see if there is any way I can make a prediction for Christmas Day.

I firstly had a look at Christmas Day stats overall since 1840. The most common group of maxima in the series is 8.1C and above. This occurred 70 times or 40%. I then had a look at the years that most closely follow this October and November. Ten years were on the list – two saw a white Christmas: 1938 and 1968. Snow often falls before and after Christmas.

xmas 2015So my guess for the weather on Christmas Day this year is for a maximum temperature of 7C after an overnight low of around 1C. With a 60% chance of rain in a stiff westerly wind there is a chance of something sleety falling.

But the fact that 20 per cent of the years in the above series saw a ‘white’ Christmas suggests that, unlike last year which I called right, there is at least *some* chance of snow falling. If you insist on having a flutter, however, Liverpool airport at 5-1 looks most generous.

Going on past form it is possible that Christmas Day will be the ‘changeover’ day for something a bit more wintry as we head into the new year – but it looks like the north Midlands northwards will be the main beneficiary of any of the white stuff

* The definition of a white Christmas used most widely – notably by the bookies – is for a single snowflake, even if it lands in the midst of heavy rain, to be observed falling in the 24 hours of 25 December at a specified location recognised by the Met Office.

** On average, snow or sleet falls in the UK 5 days in December, compared with 7.6 days in January, 6.8 days in February and 6 days in March. White Christmases were more frequent in the 18th and 19th centuries, even more so before the change of calendar in 1752, which effectively brought Christmas back by 12 days. Climate change has also brought higher average temperatures over land and sea and this generally reduces the chances of a white Christmas.

Will it be a white or green Christmas Day?

Over the next couple of weeks speculation on Christmas Day weather will inevitably build. Will Christmas be white or green?

Shoulder of Mutton lake, Wanstead PArk
Shoulder of Mutton pond, Wanstead Park

At this range it is impossible to tell from standard meteorological models though from the 15th, 10 days before the big day and when models can start to be relied upon for at least a general trend, the pieces of the weather jigsaw will start to fall into place.

Latest odds offered by bookies William Hill for a single snowflake at London Heathrow are currently 8-1, slightly longer than I’d expect at this time of year. With high pressure building and a general cooling trend this week I’d expect those odds to start to come down.

In terms of proper snow falling and settling, there has not been a white Christmas in Wanstead for over 30 years. In 2010, we could still see the Christmas card Victorian snow scene in small patches if our gardens, but these were leftovers of a previous dump, so it doesn’t count. Frustratingly, there has been snow on several Boxing Days in Wanstead (1995 and 1996) and in the weeks running up to Christmas, but not on Christmas day itself. The most typical Wanstead Christmas day weather is mild and dry, although it has rained on 12 of the last 33 Christmas days.

Tree damage by the war memorial in Wanstead High Street by Scott Whitehead
The period just before Christmas last year was very stormy

In an earlier blog I had a look at what the last 170 or so Christmas Days in London were like weatherwise and found that snow actually falling on the day is extremely rare. Since 1840 there have been just 19 occasions of snow or sleet falling on the capital on Christmas Day which equates to a probability of just under 11%. If you consider that the last ‘white Christmas’ (see note) was in 1996,  then we are well overdue one.

But the weather doesn’t adhere to human created calendars and behave like it should on any given day. But patterns in any given year can sometimes repeat though correctly predicting they will happen is more down to luck. Nevertheless I’ve had another look at my calculations for this winter and see if there is any way I can make a prediction for Christmas Day.

xmas day 2014I firstly had a look at Christmas Day stats overall since 1840. The most common group of maxima in the series is 8.1C and above. This occurred 69 times or 40%. I then had a look at the years that most closely follow this October and November. None of the years saw a white Christmas, however it is interesting to note that five out of the six years saw some snow during the month. Snow often falls before and after Christmas. Why that is no-one knows.

So my guess for the weather on Christmas Day this year is for a maximum temperature of 6C after an overnight low of around 0C. With a little rain likely I suppose there is a chance of at least something sleety falling though I’d be surprised if, on Christmas Day morning, we pull back the curtains on a wintry Dickensian scene.

* The definition of a white Christmas used most widely – notably by the bookies – is for a single snowflake, even if it lands in the midst of heavy rain, to be observed falling in the 24 hours of 25 December at a specified location recognised by the Met Office.

** On average, snow or sleet falls in the UK 5 days in December, compared with 7.6 days in January, 6.8 days in February and 6 days in March. White Christmases were more frequent in the 18th and 19th centuries, even more so before the change of calendar in 1752, which effectively brought Christmas back by 12 days. Climate change has also brought higher average temperatures over land and sea and this generally reduces the chances of a white Christmas.

170 years of Christmas Day in London

Christmas in Victorian London is often portrayed as very cold and snowy – picture perfect images of Yuletides past always scream out at us every year we open a box of Christmas cards.

The Temple, Wanstead Park, always looks that much stunning with a covering of snow
The Temple, Wanstead Park, always looks that much more stunning with a covering of snow

But a look back through the meteorological records of the Royal Observatory at Greenwich reveals a very different reality.

The 1840s and 1850s, decades where most Christmas traditions marked today began, were often very mild, wet and windy – indeed the warmest Christmas Day maximum temperature at Greenwich occurred in 1852 when the mercury reached 13.3C.

Like modern times, however, there were exceptions and 1840 was very cold – the record for Christmas Day mentions “trees coated with rime (ice) 3/8 inch thick”!

The following 20 years saw Christmas morning much milder – well over half had maxima of 6C or higher. In 1843, the year Charles Dickens first published A Christmas Carol and the public sent their first Christmas cards, the temperature reached a balmy 10.1C – though dense fog probably made it feel at least a bit more seasonal.

Frosted tree in Wanstead Park by Scott Whitehead
Frost is a common feature of Christmas Day

Four years later in 1847, the year the capital’s Tom Smith invented the Christmas cracker, things were a bit colder – a high of 4.2C and overcast with rain late evening. The following year an image of Victoria and Albert celebrating with their family around a Christmas tree appeared in the Illustrated London News. Like many things Royal down the years it really captured the public’s imagination of taking a spruce or similar evergreen into their living rooms and decorating it every Yuletide.

Christmas two years later, in 1849, was at least cold enough for something wintry to fall. London, however, was still coming to terms with its worst-ever cholera outbreak. With around 14,000 deaths from the disease Christmas was probably not a high priority that winter.

When Good King Wenceslas was first included in Carols for Christmas-Tide in 1853 the day was cold but there was still no “deep, crisp and even” snow or “rude wind’s wild lament”. The day stayed calm and clear.

OLYMPUS DIGITAL CAMERAThough the period either side of December 25th began to be marked with cold, snowy spells it would be another 11 years before London experienced its first official white Christmas in 1864. Sleet, which fell at the end of a 4-day cold spell, probably added to the drama of swimmers taking part in the first Christmas Day swim in the Serpentine, Hyde Park. With a high temperature of just 1.4C it’s quite feasible the few who braved it probably had to break the ice before they took the plunge.

Five years later London experienced another white Christmas with snow falling in a north-easterly breeze – the start of a four-day cold spell.

The joint-coldest Christmas Day on record followed five years later in 1870 with a mean temperature of -7.2C. The building of the Royal Albert Hall was scheduled to be completed by December 25th but it was not until March 29th 1871 that it was officially opened by Queen Victoria.

The remainder of Victoria’s reign was marked with far more white Christmases, a period where nearly two-thirds of Decembers were marked with extended cold, snowy spells. Fog and frost were also frequent.

With a new century and new monarch Christmas-time turned milder and London would have to wait until close to the end of Edward VII’s reign in 1909 to see a ‘white Christmas’ – a poor affair with just a bit a sleet mixed in with the rain late morning. Many probably failed to notice it but it still counts as a white Christmas according to modern bookie’s standards.

Tree damage by the war memorial in Wanstead High Street by Scott Whitehead
Christmas Day can also be stormy

Four of the 26 Christmas Days of George V’s reign were white but the mean temperatures suggest they were all marginal affairs – the core cold weather happening either before or after the 25th. Of note also is the dominance of south-westerlies that brought mild and wet weather – nine out of ten Christmas Days in the 1920s saw rain falling – far in excess of the average for rain on Christmas Day which is 47 per cent.

Just one Christmas was white during George VI’s reign, a ‘good covering of snow’ was recorded by observers at Greenwich in 1938 – the snow falling at the end of a 7-day cold spell.

Sunshine was not a dominant feature of Christmas Day prior to Queen Elizabeth II coming to the throne – the average total in Greenwich from 1877 to 1951 was just under 0.8hrs. Yet the average sunshine total for Christmas Day for the first four years of Elizabeth’s reign jumped to 5.2 hours. The 6.5 hours on Christmas Day 1952 is a record that still stands today! It is remarkable that this record was set just over a fortnight after the Great Smog contributed to the deaths of 4,000 people though other studies put the figure at 12,000 people.

trees in fogThe Clean Air Act 1956 ironically saw the return of dull Christmas Days – though 1956 was a white Christmas with a light covering of snow and a maximum of zero Celsius.

White Christmas Days that followed included 1957 (showery sleet), 1964, 1968 (sleet), and 1970.

Christmas Day 1976 was the last time snow actually fell on Christmas Day in this area though, officially, the last white Christmas was 1996 when a few sleety flakes fell in the early morning.

Christmas Days since then have been mostly mild affairs in London. Of course we had a taste of what a Dickensian Christmas Day was like four years ago when the mean temperature for the day was -1.9C. There were still small patches of snow in our gardens but these were leftovers from a previous dump, so it doesn’t count as a white Christmas. Frustratingly, there has been snow on several Boxing Days in Wanstead (1995 and 1996) and in the weeks running up to Christmas, but not on Christmas day itself.

The warmest Christmas Day in this area occurred in 2015 when a maximum of 15.2C was recorded. Warm air sourced from off the west coast of Africa sent dew points soaring, the minimum on Christmas Day night into Boxing Day did not fall below 13.5C, another record.

25122015
The synoptic chart for 0000z Christmas Day 2015 shows ever-warmer air being pumped northwards over the British Isles.

 

It is surprising how varied the weather can be on Christmas Day – we always think that Yuletide in the ‘Olden Days’ was a cold affair but a look back to 1840 reveals there were times when it was just as mild as it has been in recent years.xmas-day-since-1840

 

* Statistics for every Christmas Day since 1840 can be found here.

** The definition of a white Christmas used most widely – notably by the bookies – is for a single snowflake, even if it lands in the midst of heavy rain, to be observed falling in the 24 hours of 25 December at a specified location recognised by the Met Office.

*** In the past 170-odd years there has only been 19 white Christmases: in 1864 (sleet), 1869, 1876, 1878, 1884, 1895, 1909 (sleet), 1916, 1919, 1925, 1927, 1938, 1956, 1957 (sleet), 1964,  1968 (sleet), 1970, 1976, 1996 (sleet)