Category Archives: London weather

Wanstead colder than Aviemore

That’s not a statement that applies much, least of all the second week of January. But the current weather pattern has seen this town in the Highlands subject to the warming influence of the Atlantic, to a higher degree than London.

The above 850mb chart, typical of the past week, shows the warmer air aloft and the south of the UK seemingly cut off from outside influence.

Indeed, lack of solar heating at this time of year ensures that any thermal activity is minimal – with very little mixing of the boundary layers by day.

Wanstead Park, being a frost hollow, has seen this phenomena most days during the past week with this part of London markedly colder than elsewhere in the capital.

By the 16th the 7-day running mean at Aviemore was 2.4C higher than Wanstead!

The Christmas storm singularity

One of the best articles written regarding weather forecasting is Philip Eden’s ‘Does the Weather Have a Memory?’

The crux of the article is that certain weather types can repeat at the same time of year with one having a 100 per cent probability!

The Christmas storm singularity occurs in 84 per cent of years.

While 84 per cent certainly doesn’t mean ‘nailed on’, in the current set up of models being evenly spread between settled and stormy it can be safely guessed at this range that there will be unsettled weather around on the 25th. Whether it will affect the whole country remains uncertain.

The last big snorter of a Christmas storm I can remember in London was 2013. The entry for the 23rd into the 24th reads.

“Cloudy and breezy start grew steadily duller with rain just before noon. Rain grew heavier with some really strong gusts into evening culminating at 2am. Cloud at one point was 10kms thick. Three deaths related to weather.”

There was chaos nationwide with flooding and power cuts.

https://www.bbc.co.uk/news/uk-25512391

The average wind run for this station shows the singularity as well as the mid December settled spell we are now seeing.

London Winter Forecast 2021/22

This winter is most likely to be on the colder side of average with near normal rainfall.

While the modelled prognosis for the first half of December looks unsettled with an Atlantic influence evolving from the current chilly NW’ly to a mild SW’ly, local analogues of the climate of London suggest the season could be a bit of a rollercoaster with spells of wet, windy and mild weather alternating with dry, calm and cold.

A large factor to consider this winter is the presence of a slight La Nina that is forecast to evolve cooler.  

Given the uncertainties involved with the influence of ENSO I’ve decided to stick with analogues found in local data that stretches back to 1797.

Overall then the probabilities for the next 90 days are.

MeanProbabilityRainfallProbability
Mild (>5.9C)14%Wet (>178mm)19%
Average (5.1C – 5.9C)38%Average (107-177mm)62%
Cold (<5.1C)48%Dry (>107mm)19%

The above table doesn’t reveal a great deal in that extremes can be hidden in a month or season that finishes broadly average. So I decided to look closer at the winters that were revealed in the analogues.

December

The first month, as already mentioned, looks like it will be on the mild side with possibly a notable storm off the Atlantic before things calm down over Christmas – the period between Boxing Day and New Year’s Eve possibly presenting the best chance of any lying snow in this region.

The below graphs are a smoothed representation of the years revealed in the analogues most similar to this autumn.

What is probably most interesting is that the analogues that shared a similar ENSO / La Nina index to this autumn tended to ‘turbo charge’ any yo-yoing in the weather type, be that super-mild or abnormal cold.

December probabilties for maxima:
Mild: 48%
Average: 19%
Cold: 33%

And precipitation.
Wet: 33%
Average: 29%
Dry: 38%

So, the month overall will be mild and slightly dry

January

The first month of 2022 probably represents this region’s best chance of lying snow this winter. A mild start perhaps with a falling off of temperatures in the final third of the month and a cold spell of a week or so. As with December the influence of La Nina could tend to boost the swings in the pattern.

January probabilties for maxima:
Mild: 33%
Average: 10%
Cold: 57%

And precipitation.
Wet: 19%
Average: 43%
Dry: 38%

Greatest chances for January, then, are cold with average precipitation.

February

The second month may see a slight return of the cold spell in January before temperatures recover for a mild and wet spell in the second half.

February probabilities for maxima.
Mild: 33%
Average: 15%
Cold: 52%

And precipitation.
Wet: 38%
Average: 38%
Dry: 24%

The stats suggest on the cold side overall with average to above average rainfall. Perhaps the depth of the cold skewing any very mild second half of the month?


The extremes that no-one can forecast

As well as the very mild winter of 1989/90 the analogues also revealed the very cold winter of 1978/79. There were others but their occurence makes the probability of a repeat at either extreme at less than 10 per cent.

England’s gloriously rainy omen

What’s the most ridiculous omen for an England win in the European Championship final against Italy on Sunday? After hearing this on the radio this week I decided to try to find one.

Readers of this blog will know my theories of how the weather and big events seem to be tied together. So it is no surprise that I’ve indeed found one.

Last month, I wrote about summer washouts. The one last month that began on the 17th saw 28mm fall, possibly contributing to what was a dull spectacle; England’s 0-0 draw with Scotland at a rain-soaked Wembley.

While putting together the July list of washouts one of only six events since 1959 began on July 19th 1966. Over 20mm of rain fell, coinciding with England’s group game with France. The Three Lions won the tie thanks to a brace from Liverpool’s Roger Hunt. Days earlier they had been panned after a dull 0-0 draw with Uruguay. No-one, apart from Alf Ramsey, fancied our chances. Yet by the end of the month they were world champions.

So, in terms of football singularities, England’s is one title every 55 years? We’ll know by 11pm on Sunday.

Euro 2020, weather and Wimbledon

Four June washouts in london

Compiling a list of sunless, rainy days revealed some interesting spells of wet weather – the most miserable runs of June days in the capital since 1959.

First up was a three-day spell starting on June 25, 1974. Some 34.3mm of rain was recorded.

Next was a three-day spell starting on June 23, 1991. Some 26.3mm of rain was recorded.

Another three-day spell started on June 25, 1997. Some 36.2mm of rain was recorded.

Finally, and most recently, a two-day spell this month that began on June 17th. Some 28mm of rain was recorded.

The above spells all happened around the date of the ‘June monsoon’ singularity which has a probability of 77 per cent. Though the fact that these occurred 47 years, 30 years and 24 years ago shows that these extreme cases happen a lot less than three years in every four the singularity would suggest.

Comparing the current Northern Hemisphere pattern with 1974 suggests that while there’s just as much heat around at 850mb as there was 47 years ago, including an extreme heatwave over some Nordic countries, the air above Greenland appears colder.

Spring in Wanstead Park

Spring in this neck of the woods was really mixed.

A chilly start to March became fairly benign before ending with the warmest March day locally since at least 1959.

April then turned much colder and drier; just 2.4mm of rain fell during the month – the driest April since 2007 and fourth driest in a local rainfall series back to 1797! Sunshine was abundant with over 200 hours. But clear skies at that time of year, with a polar continental airmass, often means air frost. And the ten recorded overnight was far higher than normal.

May saw things warm up slightly but the month still finished a degree colder than average. Some 80mm of rain fell which is over one and a half times what we’d normally expect. The wettest May since 2007 – the month playing catch up on the total absence of April showers that bring the spring flowers! It was a dull month with only 126 hours of sunshine, 69 per cent of average – the dullest since 1990 was third dullest back to 1881.


In terms of flora and fauna the colder weather played havoc with the trees, bud burst coming much later than recent years. As I write this on June 6th some of the later budders like false acacia have only just come into full leaf. The birds, as they normally do, just seem to get on with it raising their young. I’m not sure what the food supply has been like but judging by the amount of healthy juvenile fledglings I’ve seen I would guess that it has been a good season so far?


Here’s the stats.
March 8C (+0.3) 30.9mm (76%) 90.9 hours (84%)24.1C on 30th (a record that had stood since 1965)
April 7.2C (-2.6) 2.4mm (5.5%) 202.6 hours (127%)
10 air frosts in April, much higher than normal
May 12.1 (-1) 80mm (156%) 125.6hours (69%)
Spring 2021: Mean Thermometer: 9.1C (1.1C below average, coldest since 2013, 111th coldest) Rain Cloud with rain: 113mm (84% of average, wettest since 2018, 150th wettest ) Sun Sun with rays: 425.4 hrs (94% of average, dullest for three years. 51st dullest) The average masked extremes.

The early March storms singularity

Storms in late February / early March occur in 88 per cent of years, according to Philip Eden’s study on singularities.

This year looks no different although the drop in air pressure looks like it will happen just in the nick of time.

The GFS op for the March 9th compared with the situation on the 2nd

A look at the past eight years shows the effects of the pattern are quite pronounced.

And a look nationwide reveals the following named storms occurred around this period.

Storm Jake, March 2, 2016

Storm Ewan, February 28, 2017

Storm Emma, March 1, 2018

Storm Karine, March 2, 2020

And going back further reveals a notable storm in the 19th century.

Luke Howard’s meteors

Attention on the bright meteor seen over the UK earlier this week got me thinking about the meteors frequently mentioned in Luke Howard’s Climate of London volumes.

Howard had a keen interest in all things atmospheric, not least this celestial phenomena. Many of his personal accounts are mentioned over a period of a decade or so including accounts of meteors overseas.

April 4, 1807

February 1, 1808

July 12, 1808

December 16, 1808

March 22, 1809

May 1, 1809

July 18, 1809

January 26, 1811

April 1, 1811

November 7, 1812

April 23, 1813

July 29,1813

February 2, 1816

December 12, 1816

August 6, 1817

Decenber 8, 1817

January 28, 1818

February 6, 1818

Grimmest winter since 1979

The last three months in east London, considering sunshine, have been the dullest for 10 years. Despite the sunny end to February just 123 hours of sun have been recorded, just under 74 per cent of the seasonal average.

With little sun, rainfall well above average, temperatures best described as average and the endless lockdown it is no wonder things felt so grim.

A couple of years ago, inspired by the blogger XMetman, I devised my own ‘grim index’ to try to rank how each winter ‘felt’.

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, after a blip in 2018-19, has been growing steadily worse.

The 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 20 of grim winters it is striking how most coincide with depressing world events, the Great War, World War 2 and the Spanish Flu pandemic.

THE STORM OF MARCH 4, 1818

Early March often brings stormy weather, a singularity that has a probability of 88 per cent!

An example of just how long this singularity has been around can be found in the early 19th century

In his book The Climate of London Luke Howard mentions that the air pressure on March 4th was the lowest measured for some 37 years. The lowest point of 28.35 inches (960mb) is remarkable in that the lowest I’ve measured in Wanstead since 2012 was 969.8mb last December!

The storm brought devastation across a wide swath of southern England with loss of life on both land and sea.
Howard’s account of the storm mentions the barometer falling an inch in 15 hours with rain after dark with the wind “raging in violent gusts from SE and SW till past midnight when it abated after much thunder and lightning”.

His friend in Manchester, Dr William Henry, wrote a storm SW caused considerable damage, delaying the London mail in Macclesfield from 8pm until 3am on the 5th, the storm raging until 3am. The barometer fell to 28.2in (955mb) at Manchester.

Character of the period for the most part tempestuous with frequent rains the barometer running through a series of sharp depressions till near the close when it suddenly assumed the elevation of fair weather Almost all the showers from the first were more or less mingled with hail

Elsewhere in Britain public ledgers also reported the storm.

Yarmouth A most tremendous gale of wind from the S to the SE with rain came on about 8pm which continued with increasing violence all night and has done considerable damage to the shipping on this part of our coast.

Deal Last night it came on to blow a most tremendous gale from the south and continued nearly the whole of the night with unabated violence at midnight it blew a complete hurricane accompanied with thunder and lightning during which several vessels in docks suffered.

Portsmouth It blew a tremendous hurricane last night from S and SSE accompanied with the highest spring rides ever remembered.

Ryde One of the severest gales of wind that has been felt here for the last 37 years was experienced last night. It commenced about 4.30pm and continued with increased violence until past 11pm during which time the greater part of the pier and several houses were demolished. The supposed damage is estimated at between £4,000 and £5,000. No lives were lost nor any damage done to the shipping.

Dartmouth We experienced a perfect hurricane last night at SSE from 6pm to 10pm

Exmouth On the 4th instant between 7pm and 8pm we had a most tremendous gale of wind about SSE with dreadful rain thunder and lightning.

Falmouth At day light this morning the wind was from the WSW moderate. About 11am it strengthened to the S and from that to SSE and since that time until 10pm it has blown a hurricane with a heavy sea.

Penzance We had a very heavy gale here on Wednesday the 4th.

Milford On the 4th it blew a very heavy storm from SW to WNW.

Leicester Wednesday night was one of the most boisterous recollected for years past. Much damage has been sustained in this town and many parts of the county.

Hull At high water about 4.30pm the wind then blowing from the SW with moderate weather the tide flowed at the Old Dock Gates 18ft 6in. After the tide had fallen from 1 to 2in the dock gates closed as usual with the ebbing of the tide which then began again to flow to the height as near as can be calculated of four or five inches thereby opening the gates again and continued flowing. The tempestuous night of Wednesday ensued the wind blew a heavy gale still from the SW and at high water at 5am Thursday morning the tide was 14ft 1in being 4 feet 5 inches less than on the preceding evening although from the spring tides having put in the water ought according to the usual state of things to have flowed higher than on the Wednesday evening

Plymouth At the commencement of the winter a few large stones were placed by themselves on the top or finished part of the Breakwater to see if they would stand the winter gales they stood all but this last and this morning I found them washed from the top and lying on the North Slope There were three of them one of nine tons and the other two of five tons each they will be replaced as soon as possible for further trial Plymouth The effects of the late thunder storm of the 4th March on a fir tree belonging to W Langmead Esq at Elfordleigh in the neighbourhood of Plymouth are too singular to be omitted and perhaps the most extraordinary ones that ever occurred in this county on such an occasion The tree in question has been long admired for its size and noble proportions being more than 100 feet high and nearly 14 feet in girth but it exists no longer having been literally shivered to pieces by the electric fluid Some of the fragments lie 260 feet from the spot and others bestrew the ground in every direction presenting altogether a scene of desolated vegetation easier to be conceived than described.