Tag Archives: East London

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

 

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July 2018: warmest month on record

July 2018 was the warmest month locally in a record going back to 1797. The mean temperature of 21.7C is 3.2C above the 1981-2010 average and exceeds the previous warmest July (1983) by 0.3C. Indeed, it is the warmest calendar month ever.

jul152018
MODIS image July 15th 2018

Just 16.7mm of rain fell, all of it coming after the 47 day long drought ended with a thunderstorm on the 27th. The amount is 38 per cent of average and is the driest July since 2010 and 7th driest in the local record.

There were 273 hours of sunshine, 142 per cent of average, making it the sunniest for five years and 10th sunniest on record.

As well as many hot days the lack of rainfall was most noticeable with catastrophic results on Wanstead Flats.

The warmest day occurred on the 26th with 34.7C.

The wettest day occurred on the 27th with 7.3mm falling.

 

 

London droughts back to 1871

A thunderstorm on July 27th has ended a dry spell that lasted nearly 7 weeks in east London. As storms go it was a fairly tame affair, just 1.3mm fell, the first rain in 47 days, 20 hours and 14 mins.

drought rankThere are many descriptions of drought but the one I am using here, for sheer simplicity of comparison back to 1871, is the definition used up until the 1990s; that is 15 consecutive days with less than 0.25mm (0.01 inches) rain on any one day.

Meteorological droughts occur in most years though obviously ones that occur in summer are far more noticeable than those in winter. Since 1871 there have been 35 calendar years where no drought has taken place.

The longest drought before this one in 2018, probably not surprising for those who remember it, occurred during the long hot summer of 1976. The fact that summer came on top of a very dry winter, rainfall that season was about a third of what was recorded here last winter, meant that water supplies were in a much worse state, with hosepipe bans common.

Other drought years to feature include 1959, which saw the 3rd sunniest summer on record, 1929 and 1995, a summer which saw one of the hottest heatwaves on record.

For the stats I’ve used local rainfall figures back to 1959 and then stats used at Kew to 1871.

individual droughts
This graphic shows droughts were most common between 2000 and 1921. Apart from this year the length of droughts seems to be declining

Looking at the results more closely I’ve divided them into their meteorological seasons.

spring drought

summer drought

autumn drought

winter drought

 

 

 

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

 

June 2018: driest on record since 1797

This June will probably be most remembered for the lack of rainfall throughout the month. I recorded just 0.7mm of rain over the 30 days – the driest June in a local record going back to 1797, 0.4mm less than the previous driest June in 1925.

fire
A fire on Wanstead Flats on Friday 29th was quickly extinguished thanks to the fire brigade

As I write this the area is now experiencing its 24th day of ‘meteorological drought’ conditions with little prospect of anything heavy anytime soon. The month was in stark contrast to May which saw may downpours associated with thunderstorms.

It was a warm month. The mean temperature finished 18.1C, exactly 2C above average, though slightly down on last June and the 7th= warmest since 1797.

Some 231.4hrs of sunshine were recorded, 130 per cent of average, making it the sunniest May for 8 years, and the 30th sunniest since 1881.

The warmest day occurred on the 25th with 30C.

The wettest day occurred on the 9th with 0.4mm falling.

Summary for June 2018

Temperature (°C):
Mean (1 minute)  17.7
Mean (min+max)   18.0
Mean Minimum     12.3
Mean Maximum     23.8
Minimum          6.4 day 12
Maximum          30.0 day 25
Highest Minimum  17.8 day 18
Lowest Maximum   17.9 day 04
Air frosts       0
Rainfall (mm):
Total for month  0.7
Wettest day      0.4 day 09
High rain rate   4.0 day 09
Rain days        1
Dry days         29
Wind (mph):
Highest Gust     18.3 day 14
Average Speed    3.1
Wind Run         2199.7 miles
Gale days        0
Pressure (mb):
Maximum          1029.9 day 21
Minimum          1008.2 day 14
Days with snow falling         0
Days with snow lying at 0900   0
Total hours of sunshine        231.4
Elsewhere in the UK it has been a very dry month across England.
0-25
Two CET stations, Rothamsted and Pershore recorded 2.2mm and 10mm respectively.
Other stations:
Northolt 0.8mm
St Bees Head: 25.2mm
Scilly: 7.6mm
Shoebury: 0mm

 

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

 

 

 

 

May 2018: warmth and thunderstorms

This May will probably be most remembered for the number of thunderstorms affecting the area. I recorded an unprecedented (in my memory) four consecutive days of thunderstorms.

convection
Convective clouds build over Wanstead Flats

It was also warm with a couple of days making the top 10 of hottest days since 1959. The mean temperature finished 15.1C, 2C warmer than average, the warmest May for seven years and the 8th= warmest since 1797.

Rainfall at 65.5mm was 128 per cent of average and slightly drier than last year.

Some 244hrs of sunshine were recorded, 134 per cent of average, making it the sunniest May for 7 years, and the 11th sunniest since 1881.

Spring finished with a mean temp of 11C, 0.8C above average, 1C cooler than last year. Rainfall at 181.9mm, was 135 per cent of average, making it the wettest spring for 10 years. Sunshine of only 411.2 hours made it the dullest spring since 2006.

The warmest day occurred on the 7th with 28.1C.

The wettest day occurred on the 29th with 29.8mm falling during a prolonged thunderstorm.

Air frosts: 0, Ground frosts: 0

This summer in east London is looking average with little to write home about weatherwise.

Summary for May 2018

Temperature (°C):
Mean (1 minute)  14.7
Mean (min+max)   15.1
Mean Minimum     9.0
Mean Maximum     21.1
Minimum          1.8 day 02
Maximum          28.1 day 07
Highest Minimum  15.7 day 31
Lowest Maximum   14.1 day 02
Air frosts       0
Rainfall (mm):
Total for month  65.5
Wettest day      29.8 day 29
High rain rate   60.4 day 28
Rain days        9
Dry days         22
Wind (mph):
Highest Gust     20.6 day 02
Average Speed    2.4
Wind Run         1808.0 miles
Gale days        0
Pressure (mb):
Maximum          1027.4 day 16
Minimum          1001.5 day 02
Days with snow falling         0
Days with snow lying at 0900   0

 

 

 

 

Thunderstorms 26th-27th May 2018

Last night’s intense thunderstorm was probably most notable for its high-level sheet lightning than rainfall, thunder or fork lightning.

At my own station I recorded 4.8mm of rain which at its heaviest fell at a rate of 24.1mm/hr at 0046. To put that into perspective that’s just under a quarter of the rainfall rate during the thunderstorm at the beginning of last June. Rainfall in nearby Woodford Wells fell at a rate of 35.6mm/hr at 0040.

The rainfall was much heavier to the west of London. Screen Shot 2018-05-27 at 13.06.37

Also of note was how warm the night was. A low of 15.3C made it the 8th equal warmest May night since 1959.

There’s probably going to be a few more storms this bank holiday weekend though it remains to be seen whether this is going to be a classic summer for storms.

At it’s peak at 2305 there were 16800 strikes, according to Blitzortung.

Lightning from the storm in the early hours of the 27th caused a fire at a house in Romford.

There is an account of the family’s ordeal here.

Screen Shot 2018-05-27 at 15.13.10

Here’s a few traces from the station.

Screen Shot 2018-05-26 at 23.39.37

Screen Shot 2018-05-27 at 12.51.20

Screen Shot 2018-05-27 at 12.51.37

Screen Shot 2018-05-27 at 12.52.18

Around the capital and the south east

Elsewhere in London there was some excellent footage posted on social media.

Screen Shot 2018-05-27 at 13.03.15

 

The 27th was fairly quiet but with abundant sunshine and little wind it wasn’t long before more storms, this time homegrown, developed over the Midlands and the south. Severe flash flooding was reported in the Selly Oak area of Birmingham after a month’s worth of rain fell.

And as dusk approached a huge storm toward to the north-west of London and Chilterns. With little wind the storm stayed more or less in situ, expending all its energy with the most amazing lightshow – lightning within cloud that became more and more vivid as darkness approached.

Because these storms can reach heights of 29,000ft – roughly the height of Everest – they can be seen from over 40 miles away.

I had a go myself.

Screen Shot 2018-05-28 at 10.34.52

Not bad but the best footage I’ve seen was captured by Simon Cardy from east London and can be seen here.

 

 

I also took this video.

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

Two April heatwaves compared

The stats are in and the average maxima for the past few days’ heatwave is 1C lower than the hot spell in 2011: a positive anomaly of 10.6C over six days.

Screen Shot 2018-04-23 at 13.34.29Screen Shot 2018-04-23 at 13.34.21

Although this year’s spell pipped the previous April high temp by 0.2C, the 2011 spell saw slightly higher temperatures and were recorded in a month that finished 3.3C above average – the average for this April is likely to finish only 2C above average.

April 2011 also saw just 3.3mm of rain recorded. The rainfall so far this month is already at 36.7mm, with more likely before the end of the month.

The spell in 2011 saw 74 hours of sunshine in total while this spell only saw 58 hours.

In terms of this summer it is quite possible that we won’t see a week with higher maximum anomalies or more sunshine than we saw across the southeast this week. To give you any idea of just how anon. warm last week was here is what the equivalent temperatures would be at the end of July, on average the warmest time of the year.

25th 29.8
26th 35.4
27th 39.2 (102.6F)
28th 37.7
29th 32.1
30th 33.3

* The Met Office definition of a heatwave (the same as the WMO) states:  “When the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 °C, the normal period being 1961-1990”.

 

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Screen Shot 2018-04-23 at 13.44.09
The large anomalies of the past few days can be seen on this thermo trace