Tag Archives: London weather

Wild equinox brings memories of childhood

Wild weather in the run up to the autumnal equinox was frequently a staple of the Septembers of my childhood but it has been absent in recent years.

Since 2013 I have been recording the ‘wind run’ data on my AWS, a stat generated by the amount of times the anemometer spins.

wind run

The results show there has been nearly two-and-a-half times more wind than the 5-year average.

Stormy weather over the equinox is one of the less frequent recurring singularities. The meteorologist Philip Eden a few years ago noted that ‘Mid-September storms’ during the period of 17th to 24th September had a frequency of 60 per cent.

20th
The wind run was the highest on 20th
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London’s August extremes since 1959

I’m running out of superlatives for this summer. There has already been 15 days where the temperature has reached or exceeded 30C, two more than 1976!

However, the mean temperature has not been as intense as that classic summer where two heatwaves of five days and four days length were featured during the season. This summer has so far only seen one similar heatwave of 5 days length.

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

august top ten wans

august SJP

august heathrow

Some national UK August values according to TORRO

Hottest: 38.5C Brogdale, near Faversham, Kent – 10th 2003
Coldest: -4.5C Lagganlia, Highland – 21st 1973
Wettest: 238.8 Cannington, Somerset – 18th 1924

In terms of climatology August maxima, considering the 1981-2010 average, shows a fairly steady decrease through the month, though around the 15th there is often a spike before a steady decrease to month’s end. This would reflect the late August winds singularity which occurs every year around the 20th at 67 per cent probability.

august av max

The average rainfall graphic shows that downpour amounts are fairly random from year to year. The driest days are the 15th and the 30th.

aug av rain

 

London’s July extremes since 1959

With the ultra dry and warm month of June many feel the rest of summer will remain hot and dry. Recent weather patterns have seen much high pressure to our north keeping us dry and mostly sunny but protected from any humid Spanish plumes.

A look at local east London stats shows that half of the last 10 July months have been warmer than average while only two have been much 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 July.

july1959WAN

july heathrow

sjp july

Some national UK July values according to TORRO

 

Hottest: 19th 2006: 36.5C at Wisley, Surrey.
Coldest: 15th 1977: -2.5C at Lagganlia, Highland.
Wettest: 18th 1955: 279.4.8mm at Martinstown Dorset.

july av mxIn terms of climatology July maxima, considering the 1981-2010 average, shows a fairly steady increase through the month, though around the 17th there is often a dip before a warm end. This would reflect the July heatwave singularity which occurs every year at 80 per cent probability.

The average rainfall graphic shows that downpour amounts are fairly random from year to year. The driest days are the 1st and the 25th. july av rn

 

London’s June extremes since 1959

With the recent warms months of April and May you’d be forgiven for thinking that we’re in for a hot summer. Indeed the recent pattern of weather, would it repeat over the next month, could see many maxima records tumbling.

A look at local east London stats shows that six of the last 10 Junes have been warmer than average while half have been much 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 June.

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

Snow has been known to fall in June, in 1975.

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

june extremes wans

heathrow june

june sjp

The 10 driest Junes were:

 

Some UK May values according to TORRO

Hottest: 29th 1957: 35.6C at Camden Square, London. Also Southampton 28th 1976
Coldest: 9th 1955: -5.6C at Dalwhinnie, Highland. Also June 1st and 3rd 1962: Santon Downham, Norfolk
Wettest: 28th 1917: 242.8mm at Bruton, Somerset

Screen Shot 2018-06-06 at 12.11.18In terms of climatology June maxima, considering the 1981-2010 average, shows a gradual increase through the month, though around the 19th to the 21st there is often a dip before a warm end. This would reflect the June Monsoon which occurs every year at 77 per cent probability.

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

Screen Shot 2018-06-06 at 12.29.10

 

 

 

 

More anomalous warmth for late May Bank Holiday?

Weather models are hinting that this coming bank holiday weekend could be very warm indeed, with one WX Charts animation suggesting that a positive anomaly of 12C could be possible on Monday.

A date record looks a formality and, unless there’s a downgrade, new monthly high temperature records at stations across the south-east look a possibility.

While it looks very warm it is too early to start talking about heatwaves. And, considering the pattern since late February, with hot and cold alternating weekly, a brief return to much cooler conditions at the beginning of June can’t be ruled out.

The British record high temperature for May is 32.8C, reached on two occasions:

Camden Square, London May 22nd 1922. The same station recorded this value again on May 29th 1944, along with Regents Park, Horsham and Tunbridge Wells.

The national date record for the 28th, according to TORRO, is 30.6C at Camden Square.

Locally the highest temperature recorded in this area in May is 32.1C on May 27th 2005. The date record I recorded is 26.5C in 2012.

 

 

GIF

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 11 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 the top 5 maxima, made up 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.

 

wanstead april

april SJP

april hth

 

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

 

 

 

 

 

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

Poor start to June? That’ll be the Euro monsoon

Widespread heavy rain and gales across the UK have made the start of summer feel very unseasonal. But the conditions, which follow an extended period of mostly dry weather, are very typical for early June.

june rainfall with record
The pattern for June over the past 10 years reveals the month often starts unsettled before drying up in the final week

The ‘NW European monsoon’ is one of the most reliable ‘singularities’ on the annual weather calendar. Though it sounds very unscientific that the atmosphere can remember how it behaved on a certain date in previous years much statistical work over the past 170 years highlight tendencies for unusual weather at particular times of the year. These tendencies were first identified by the German climatologist, A.Schmauss, in 1938.

While the pattern isn’t set in stone statistics show that the probability of the euro monsoon occurring between June 1st and 21st is 77 per cent.

GFS rain to 15th
The GFS operational run suggests an unsettled outlook

One of the most notable inclement spells of weather in June happened during the D-Day landings in 1944.

With the changes in ice at the North and South Poles, together with the massive positive temperature anomalies last winter,  it would be thought logical that this would have some bearing on the general pattern this year. But polar ice is only one variable to consider when trying to predict the world’s climate.

 

 

The March blizzard of 1952

Warm sunshine looks likely to bring London’s first 20°C this week but the weather 65 years ago couldn’t have been more different.

180029031952
This chart shows the Synoptic setup at 1800h on 29th, the peak of the blizzard with F5 – F6 easterly winds, courtesy of the Met Office

A cold easterly airflow on March 29th and 30th 1952 affecting the southern half of England brought heavy snow whipped into drifts up to 6ft deep in parts of the Chilterns.

According to the Royal Meteorological Society’s weather log the snow varied from 3 to 6 inches and reached 10 inches at Northolt.

Squally winds, which gusted to 60 mph, blocked 330 main roads across the south. In places the temperature on the 29th remained below freezing all day – the snowstorm was probably the worst to affect southern England in late March since 1916.

The wintry weather followed a dry and fairly non-descript winter and must have been quite a shock at the end of what had been a fairly mild March.

Bernard Burton, of Wokingham, has a clear recollection of the event: “I remember the day very well as the Oxford/Cambridge boat race was held that afternoon. I was 14 at the time, and my brother-in-law gave me a ticket for a place on a launch to watch the race.

“My home was in Tooting at the time, and I took the bus to Westminster pier to catch the launch. I recall sitting upstairs on the bus with a thick layer of snow covering the front facing windows, but the roads and pavements were mainly slushy.”

Bernard, who runs Wokingham Weather, added: “I then spent one of the most miserable afternoons I can recall. There was a ‘lounge’ on the boat, which was warm, but was also full of diesel fumes and was very noisy. I alternately stood outside on the deck until the cold got too much, or went below for warmth until the fumes got the better of me.

“I recall bleak views of London with snow on roofs, in a poor grey afternoon light, but I think it was mainly dry at that time, although there may have been slight sleety rain.

“The boat race itself was a close one, but the crowds that usually lined the banks of the river were absent, just a few hardy stragglers, and by the time of the race I had a headache, probably brought on by the fumes. For my part, I couldn’t wait to get back to Westminster and back home to thaw out.”

John Hall, who was three at the time, said: ” I, sadly, don’t have any memory of it at all. That’s in spite of the fact that we apparently moved house from Cranleigh to Effingham (about 15 miles away) on the day of the blizzard.

“According to my father it snowed all day but the following day – which he reckoned was the 1st of April – the weather was glorious and all the snow was gone by noon. I don’t think his memory is quite in accordance with the facts, but of course that’s common with memories of past weather.”

The snow didn’t last long. March 31st saw temps rise to 5C; much of the snow had melted in the strong spring sunshine by April 1st. By the 3rd an Atlantic ridge of high pressure had moved in, raising temperatures to over 10C.

kew
Stats for Kew suggest there was 21cm of level snow

1952 produced two more weather shocks. On August 15th and 16th over 220mm of rain fell on the hills above Lynmouth, Devon, leading to flash flooding of the village and the loss of 34 lives.

Months later, a large anticyclone during the last of five days of December produced the notorious ‘pea souper’ fog that contributed to the death of thousands of Londoners. This fog, initially freezing, became very dense and was directly responsible for the Clean Air Act enabled in 1956.

You can find an analysis of the unfolding pattern that produced the blizzard here. And here’s Xmetman’s take on the event.