Category Archives: History

London’s May extremes since 1959

Ne’er cast a clout till May is out. With the recent March and April weather being so variable it would be wise to bear in mind this old saying, especially with fine and warm weather forecast for the Bank Holiday weekend.

A look at local east London stats, however, shows that seven of the last 10 Mays have been warmer and drier than average.

I’ve put together a few top 10s of stats for Wanstead, St James’s Park and Heathrow for the month of April.

Probably most notable from the below values is that recent Mays have been devoid of extreme cool temperatures and rainfall.

With nights now relatively short air frosts are uncommon though the odd ground frost can still strike on a clear night.

Snow can fall in May – one example being 1979 in the higher parts of the capital – but after the first week it is extremely rare.

Rain is usually most frequent in the last week of the month.

wanstead may

SJP may

heathrow may

 

 

 

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Some UK May values according to TORRO

Hottest: 22nd 1922: 32.8C at Camden Square, London.
Coldest: 2nd 1917: -9.4C at Lynford, Norfolk
Wettest: 8th 1884: 172.2 at Seathwaite, Cumbria

 

In terms of climatology May maxima, considering the 1981-2010 average, shows a gradual increase through the month, though around the 25th there is often a brief dip before a warm end.

The average rainfall graphic reflects this, showing a three-day wetter spell after the 24th.

max max

 

may rain

 

 

London’s April extremes since 1959

April showers bring spring flowers… so the saying goes though a look at local east London stats shows that eight of the last 12 Aprils have been drier than average, some remarkably so.

I’ve put together a few top 10s of stats for Wanstead, St James’s Park and Heathrow for the month of April.

Probably most notable from the below values is that 5 of the top 7 maxima were recorded during a warm spell in 2011.

Frosts can be common and are often sharp, playing havoc with budding plants

Snow can fall in April – a good few inches fell early in the month in 2008 – though any accumulation is usually short lived.

Rain – the characteristic April showers – is usually most frequent at the end of the month.

 

april updated 1959

SJP april

heathrow apr

 

The chart slideshow below show the synoptic situation which brought a notable warm spell in the second half of April 2011.

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Some UK April values according to TORRO

Hottest: 16th 1949: 29.4C at Camden Square, London.
Coldest: 2nd 1917: -15C at Newton Rigg, Cumbria
Wettest: 22nd 1970: 182.1mm at Seathwaite, Cumbria

In terms of climatology April maxima, considering the 1981-2010 average, shows a gradual increase through the month, though around the 21st there is often a jump of 3-4C, the start of a warm spell before rain arrives at month’s end.

The average rainfall graphic reflects this, showing a three-day drier spell after the 20th.

april max

april rain

 

 

 

 

 

‘So much for global warming…’

Since notably cold weather struck at the end of February I’ve lost count of the number of times I’ve heard this phrase uttered by the public and some sections of the press.

Top 20 cold
Top 20 cold anomalies

The ‘Beast from the East’ (versions 1.0 and 2.0) really captured the imagination in an age where everything has to have a label slapped on it; any message that these cold spells are ‘weather’ and not ‘climate’ seems to get lost.

Both spells, indeed the general pattern of our late winter weather, were driven by the stratospheric sudden warming event that lead to a split polar vortex in February – leading to a very cold end to the month and a mean temperature anomaly of -2.5C, the greatest monthly anomaly since March 2013.

To put it into perspective, however, it was nothing like some of the anomalies that occurred in the early 19th century: January 1814, for example, saw a monthly anomaly of -8.2C and coincided with the last occasion a frost fair was held on the Thames. Januaries back then were generally very cold, the 1801-1831 average monthly mean was -3C, that’s 8C colder than the most recent 1981-2010 average!

So climate now is much warmer but that is not to say that anomalously cold months can’t happen. February 1986 saw an anomaly of -5.6C, the 13th= greatest cold anomaly in my local dataset going back to 1797.

top 20 warm
Top 20 warm anomalies

The cold December of 2010 recorded an anomaly of -4.2C, 76th= greatest cold anomaly, while anomalies of -4.1C recorded in January 1979 and March 2013 were 77th=.

With the warming climate it is no surprise that most warm months happened very recently. The balmy month of December 2015  saw a positive anomaly of 5.4C.

The ‘Beast from the East 2.0’ was caused by a narrow tongue of extremely cold air from Russia scoring a direct hit on the UK. The odds of this happening must have been low but it is an example of how, when the synoptics of the atmosphere line up perfectly, anything is possible.

And it is an example how even in a warming climate the UK can still be subject to anomalous cold and warmth at any time of the year.

As the author Mark Twain reportedly once said: “The climate is what you expect; the weather is what you get.”

gfs
The upper air anomaly of the ‘Beast from the East 2.0’. 
anom
This graphic shows positive and negative monthly anomalies since 1797 against a generally warming climate

Because the above graphic is crowded I created one of anomalies since 1970. The upward trend is the same.

1970

march 1st

Beast MkII or just a late March cold spell?

After the severe spell at the end of February that lasted into this month there’s lots of excitement / dread (*delete as appropriate) that the synoptic conditions that brought very cold air from our east is about to return.

The latest run on the GFS model shows that very cold air (-10C at 5,000ft) could be over us by next Sunday, with the ECM 12Z operational looking particular cold. ec

Snow this late in the year is very rare in the London area though, if the conditions are right, a blizzard is not impossible, as happened during the spring of 1952 when a two-day blizzard at the end of March brought drifts up to 6ft deep in the Chilterns.

Much more likely will be severe, possibly record breaking frosts. The coldest March night since 1959 across the London area occurred on the 3rd in 1965 with -7.4C recorded at Heathrow. Central London fell to -5C on the same night.

A look back at cold spells in March reveals that while snow was very scarce in London and the Home Counties it can be common on high ground from the Peak District northwards.

A history of March cold

1812: Luke Howard in The Climate of London noted that “great inclemency of the weather” on the 21st March disrupted mail deliveries between the north of Scotland and  Carlisle. The road between Appleby and Brough was impassable because of snow and between Sheffield and Manchester and Bradford and Halifax the snow had drifted from “two to three yards deep”.

Mail deliveries were also disrupted across South Wales.
In Plymouth a “a most tremendous gale from SW the whole of last night and this morning” brought flooding.
Howard’s account would confirm a classic battleground scenario of mild Atlantic air from the south pushing against cold Polar continental air in the north.
His own records from Stratford show a couple of cold days from the 16th, highs never lower than 2C, the coldest night on the 24th, being -4.4C. On the 20th he mentions snow in the morning followed by rain.
Wanstead mean: 4.9C (-2.8C) rainfall: 74.4mm (183%)

The following accounts of cold spells in March are recorded on the site London Weather.

1962: The first ‘spring’ month was colder than any month during the preceding winter. Frosty nights were much more frequent than normal, and sleet or snow fell on 10 days, although amounts were often trivial . On the 5th, the maximum temperature was only 2.2 C. Towards the end of the month, north to northeast winds were replaced by somewhat, cloudier milder, and moister south-westerlies. Atlantic fronts brought rain bands, and on the 29th nearly 10mm was measured.
Wanstead mean: 3.3C (-4.4C) rainfall: 36.5mm (90%) sun: 95.4hrs (88%)

1964: The first week of March was mostly cold with wintry showers and a fresh northeast wind. The temperature on the 7th only reached 2.3C. The second week was changeable and milder, and the high on the 13th was near 14C., but on the 15th, rain turned to sleet and gave a total of 26mm as cold air slowly encroached from the east. Nearly 15mm of rain fell on the 19th as milder air returned, but the rest of the month stayed mostly rather cold and changeable.
Wanstead mean: 4.9C (-2.8C) rainfall: 80.4mm (90%) sun: 63.5hrs (58%)

1969: The first week was mainly dry, and although dull and cold at first, it became fairly sunny and milder but with severe frosts. Overnight on the 6th/7th the minimum temperature was close to minus 8C. During the second week it became dull and wet, but after a cold start temperatures rose above average. Cold north-easterlies returned on the 16th with a high of only 3C., and cloudy, rather cold, and often wet, weather persisted until westerlies returned on the 29th.
Wanstead mean: 4.6C (-3.1C) rainfall: 53.2mm (131%) sun: 55.8hrs (51%)

1979: The first 12 days of March were changeable and windy with temperatures mostly above average. A wave depression formed on a cold front and produced 23mm of rain on the 13th, and as this depression became slow moving to the east of the country the rain turned to sleet and snow on the 14th, and continued into the 15th and 16th with highs near 3C. After mid month, the weather became less unsettled and milder, and the high on the 25th was near 15C.
Wanstead mean: 5.8C (-1.9C) rainfall: 96.5mm (237%) sun: 100.5hrs (92%)

1985: After a changeable start to the month, pressure built, and it became mostly dry, although often rather cloudy, with temperatures close to normal. On the 15th, showery rain turned to snow during the morning, and several cold and unsettled days followed. Sleet or snow fell on 5 days, and on the 21st the temperature failed to rise above 5C. Sharp frosts occurred, and although it then became less cold, the 26th was a miserable day with 11m of rain falling.
Wanstead mean: 5.9C (-1.8C) rainfall: 44.1mm (108%) sun: 100.5hrs (87.4%)

Record cold pools and snowfalls

This week has the potential to see new temperature records set or matched as very cold air moves in off the continent.

Whilst amounts and location of snow are very difficult to estimate at more than 24hrs to 48hrs away there is no doubt that the incoming air is very cold indeed.

In the early hours of Wednesday one weather model is showing extremely cold air (496-504 DAM ie very low thickness) just off the coast of Scotland. In the last 60 years there have been only three occasions where air approaching this thickness (500 DAM and lower) has been recorded in the UK:

February 1st 1956: Hemsby, Norfolk
February 7th 1969 at Stornoway, Outer Hebrides
January 12th 1987 at Hemsby.

thick
Radiosonde (weather balloon) ascents will make very interesting reading this week

With the deep cold air in place the potential for snowfall comes once the air starts to become unstable. East London, and much of the east coast, best falls come where convergence lines ‘streamers’ form.

streamer
One example of a streamer is forecast to occur on Tuesday

If persistent, these ‘Christmas tree’ features are capable of producing snowfall accumulating at the rate of 5–7cm per hour in especially cold
outbreaks, albeit often very locally. The steep thermal contrast between the very cold air and the current warm anomaly in the North Sea could make any snowfall very heavy indeed.

Streamers during the cold spell of January 1987 saw 30cm fall widely with some up to 65cm in Kent and 45cm in south Essex. Parts of Cornwall saw up to 40cm.

During a cold spell in February 2009 thundersnow was recorded – the favoured spot this time being parts of Surrey which saw 30cm.

Personally the most snow I have recorded during a cold spell was in February 1991. A very deep cold pool, not unlike what is forecast this week, covered much of the south. in air approaching 500 DAM. Days and days of snow followed dumping knee-deep powder in my local park in suburban East London. Reported depths included 20cm at St James’ Park in the centre of London, and 38cm at Rettendon, Essex.

There is a very good paper on cold pools and snowfall here.

beast

 

 

 

The severe cold spell of February 1991

The cold spell of February 1991 saw unusually deep snowfall in central London. The 20cm recorded at St James’s Park on the 8th was the greatest cover recorded at the site since the severe winter of 1962/63.

summ821991
Courtesy of the Met Office

My own memory of the event was that the synoptics evolved fairly quickly. I was away at university at the time and had to be back for a family event that weekend. After seeing a forecast predicting that a foot of snow was on the way I jumped on a train a day earlier than planned and returned to London. The following morning all hell had broken loose as deep snow paralysed public transport.

Snow fell on the following 6 days with no thawing as the temperature remained below zero until the 10th. The maximum of the 7th was -3C. By the 9th there was widely 20cm of level powdery snow lying. Getting around was difficult – I remember some drifts during walks into town were thigh high.

The month saw the three coldest February days of the last 60 years in central London.

By the end of the 19th all of the British Isles were snow free.

February 1991
February 1991 in suburban east London

The nine charts below show how a strong ridge of high pressure from an anticyclone over northern Sweden on the 5th brought very cold air and heavy snowfall over the following days.

These significant weather charts show the snow depths at noon from 6th to the 13th.

 

summ1021991
Courtesy of the Met Office

Ian McCaskill’s late evening BBC forecast on February 6th.

Francis Wilson’s breakfast telly forecast on February 7th 1991: “Temperatures rising from -11 to -5C. Depths in excess of a foot. It’s all downhill from now.”

Harlow, Essex, during the cold spell.

Past weather to rescue future reporting

“Worst floods ever!” Hyperbolic reporting of weather events is nothing new; whenever the UK is hit by the latest named storm breathless news anchors often try to portray atrocious conditions as ‘unprecedented’. This may soon change thanks to a project that uses citizen science.

Operation Weather Rescue, the citizen science project which last year processed Ben Nevis and Fort William data from between 1883 and 1904, has now recovered thousands of European observations from past Daily Weather Reports compiled from 1900-1903.

Though reanalysis data of the northern hemisphere back to 1851 have been available for some years the maps don’t give enough detail to be able to compare if an old storm has the same pressure characteristics as a modern storm. Evidence of impacts is restricted to fixed observations such as temperature, rainfall and archive press reports.

Weather Rescue: “We want to learn about the frequency of intense storms in the past to compare with now and these rescued observations will significantly improve our understanding.”

The latest release of data features pressure plots from June 1903 that tie in with the record-breaking 59-hour deluge that left much of the London Borough of Redbridge underwater. The following October, nationally, was the wettest month ever recorded in the UK.

Further recovery of these archived data, with the help of thousands of volunteers, will prove invaluable to our understanding of high-impact weather, and if storms are getting worse.

This latest example of Big Data could also offer huge benefits to the insurance and reinsurance industries, as well as planning engineers, as the resolution of climate models steadily improve.

But on a purely weather reporting scale it should also be possible to one day provide the media with a quickly accessible database of weather events going back over a century, enabling them to judge whether the latest storm really is the worst in 100 years.

In this age of clickbait journalism, however, I’m not holding my breath!

rescue

Murphy’s winter and weather prophets

It is 180 years ago this month that Patrick Murphy shot to fame after successfully predicting one of the coldest Januaries on record.

murphy
anon, “The Modern Phenomenon of a Murphy the Gullcatcher of 1838” London Saturday Journal

The month, which had started mild, completely changed during the weekend of the 8th as a SE’ly wind set in. Hard frosts and snow became a daily feature with considerable falls across Scotland, disrupting mail and causing hardship for people and livestock.

By the 20th some of the lowest temperatures of the 19th century were recorded in London. At Greenwich -16C (-11C at midday) was reported at sunrise, while Blackheath saw -20C and Beckenham -26C. By the 27th the Thames at Greenwich was completely covered with ice at high water and elsewhere in the estuary ice floes were reported.

In some parts of northern Scotland, snow was noted to fall on most days between January 8th and May 3rd. Snow was also noted in upland areas of NE Scotland in June.

‘Murphy’s Winter’ as it became known made the astrologer from Cork a small fortune from the sale of an almanac, the contents of which also successfully listed the actual date when the frost would be at its most severe.

It was possibly the first long-range weather prediction that people through the ages seem to love, whether they are right or wrong.

Many characters have emerged over the years. Yorkshire’s Bill Foggitt, who used natural signals and animal behaviour during the previous autumn, was popular in the 1980s especially when he made a prediction of a harsh winter.

Others, including the Daily Express, who probably shouldn’t be mentioned in the same breath as Foggitt, are more about the clicks they hope to generate for their publishers than any earnest attempt at being right.

  • The mean temperature locally in January 1838 was -1.5C, the second coldest January in a series going back to 1797, and as cold as January 1963.
  • mean

 

 

The cold spell of January 1826

This weekend marks the start of a cold spell that brought widespread wintry conditions across Britain.

Entries in Luke Howard’s Climate of London detail several instances of the wintry weather reported nationwideScreen Shot 2018-01-06 at 01.41.17.

In London the freeze lasted 10 days, briefly losing its grip on the 19th, before returning in the final week. At its lowest on the night of the 14th the temperature fell to 10F (-12C). Despite the intense cold their was little precipitation in this area. However, across the country came reports of deep snow and hardship for shipping.

Gale force easterly winds were reported in Plymouth, Falmouth, Liverpool and Portsmouth on January 7th and 8th. On January 9th a ‘hard ENE’ly gale’ was reported at Deal, Kent.

A report reads: “It has continued blowing strong from the eastward all this day. On Thursday morning between one and two o’clock as a person was passing through Paternoster Row he observed the watchman on that beat in a state of complete paralysis and insensibility occasioned by the frost.

“He had him immediately removed to the watch house of Farringdon, within where he had not long arrived when a fellow sufferer was brought in by two of the patrol who found him in his box in Stationers Court, Ludgate Hill, absolutely frozen and unable to articulate a syllable.

“Both were immediately placed near the fire the influence of which combined with the administration of warm cordials shortly restored their suspended faculties. The thermometer at the Royal Exchange yesterday at 12 o’clock stood at 28F.”

An entry on January 14th, nearly a week into the freeze, reported a Thames “choked up with ice”.

“The river is so completely choked up with ice that the fishing boats with fish dare not come higher up than Limehouse. Putney Bridge arches are choked up with ice formed by the ebbing and flowing of the tide to a great height. At one o’clock yesterday afternoon (16th) the fog in the city was as dense as we ever recollect to have known it.

“Lamps and candles were lighted in all the shops and offices and the carriages in the streets dared not exceed a foot pace. At the same time five miles from town the atmosphere was clear and unclouded with a brilliant sun.

“Fahrenheit’s thermometer stood at 14F at 8 o’clock in the morning.

Around Britain

Newcastle: on Sunday morning last a severe frost set in here and has continued since. A considerable quantity of snow has fallen during the week.

Sunderland: the river Wear has been frozen over for the last four days down to Hilton Ferry within four miles of this town. The navigation above that place is entirely suspended.

Carlisle: a smart frost set in here on Monday morning and has continued gradually increasing up to this day Friday in severity. The river Eden is more than half frozen over near the bridge and many persons are diverting themselves on its surface. On Tuesday we had a partial fall of snow which still continues.

Westmorland: on Stainmore the weather has been more severe during the last week than it has been known for four years past. The frost is not only more than usually intense but the snow lies in fearful drifts and the wind on Friday and Saturday blew a perfect hurricane rendering it extremely difficult if not dangerous to travel.

Chester: the frost during the last week has been intensely severe and the wind is gentle and blowing almost constantly from the eastward. The thermometer on Saturday morning stood at 17F or 15F below the freezing point.

Manchester: on Friday last the temperature in the city was as low as 16F and this in the very centre of the town where the crowded buildings and immense fires kept in the manufactories must have had some effect on the atmosphere. On the 18th of January 1814 the extreme temperature was 22 below the freezing point. On the 21st of February 1810 it was the same.

Liverpool: the weather during the last week has been intensely cold, the thermometer for the last few days having been lower than during the past five years. A self registering thermometer denoted the extreme of cold on Saturday night to have been 19F and yesterday, Sunday morning at half past seven, it stood at 20F. It is very probable the present weather may continue several days as it commenced with the new moon.

Bridgewater: our river is so completely frozen over as to impede the navigation fortunately there is a good supply of coals in the town.

Canterbury: On January 17th the river Medway is frozen over and the navigation is stopped. The merchants have advanced the price of coals six shillings a chaldron.

The Royal Military Canal being now completely frozen over numerous parties are daily skating thereon. It is not unusual to take a breakfast at Hythe, a luncheon at Rye (about 20 miles glide) and return to Hythe to dinner.

On the continent

Elsineur:  the sound is full of ice and the navigation suspended. (January 14th ).

Hamburg: the frost is very intense and every appearance of its continuance. Extract from a private letter dated ‘Cadiz Jan 24’: ‘We have had terrible gales at this place so violent that upwards of two hundred and fifty vessels were driven on shore.

Rotterdam: We have had frost again from the 25th but very moderate and the ice has but little increased. The wind prevails from the eastward and there is no appearance of a thaw.

Antwerp: the river continues full of drift ice. An easterly wind took place on the 25th January. The ice decreases very fast (31st) and if the thaw continues for which there is every appearance the river will be navigable in two days.

The mean temperature for the month finished 0.7C, the 14th coldest January in London back to 1797. Just 5.1mm of precipitation was recorded, the second driest January in the series. Screen Shot 2018-01-06 at 22.31.39

London Grimness index

The last three months in east London have been sunnier than average – hard to believe as we move into a regime of easterlies that will bring showers and anticyclonic gloom.

Screen Shot 2017-12-21 at 21.30.14
A sunless outlook from the Met Office last December

With no sun and short days  it is no surprise that many are probably already feeling short-changed in the solar stakes.

A blog by XMetman on a ‘grimness index’ got me thinking how London fairs in terms of sunshine, temperature and rain in any given winter season.

Using the same criteria, and assuming that most people welcome sunshine, it can be seen that since the least grim winter of 2007-08, the season, over the past 10 years, has been growing steadily worse.

Screen Shot 2017-12-21 at 21.51.54The grimmest winter, considering statistics back to 1881, was, ironically, the 1978-79 ‘Winter of Discontent’ when, again ironically, ‘Sunny Jim’ Callaghan was in Downing Street as widespread strikes coincided with the coldest winter for 16 years. On looking at the Top 10 of grim winters it is striking how most coincide with depressing world events, the Great War, World War 2 and the Korean War!

grim index

The Tory ‘Crisis? What Crisis?’ campaign was probably my first memory of a general election broadcast.