First frosts in East London since 1959

Although many parts of the UK have already recorded their first air frost this part of the capital, being so built up and close to the City, remains frost free.

Although many may think that frosts are getting later a look back through local statistics to 1959 shows these events are very random.

The scatter graph below illustrates this.

first frost in east london a

Taking out the winters of 1974/75 and 2002/03, which didn’t see frosts until February and January respectively, the scatter can be seen better here.

first frost in east london b

The median for the first frost is November 6th with an average minimum of -1.4C.

October frosts can be a precursor to a mild winter much in the same way that heavy October snowfall in the Alps has lead to an awful season. But there are exceptions, as happened in 2008/09.

* To record an air frost the temperature must fall to -0.1C or lower.

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September 2018: average, dry and sunny

September was most notable for the amount of cold nights. The record minimum was matched together with three further new entries into the top ten list of extremes back to 1959 – a rare occurrence.

The mean temperature finished 15.2C, 0.2C below average, ending a run of 5 months where the mean has been, at times, well above average.

Some 32.6mm of rainfall was recorded, 63 per cent of the 1981-2010 average. Some 183 hours of sunshine were recorded, 132 per cent of average and more than August!

For the first time in years the autumnal equinox period was very stormy, as shown by this graph.

wind run

To view full stats follow this link:http://1drv.ms/1kiTuzv

Summary for September 2018 to follow…

 

London’s October extremes since 1959

October is one of those months that can see both ends of the spectrum; from calm ‘mists and mellow fruitfulness’ and, rarely, frost, to wet and wild systems whistling in off the Atlantic, best known being the 1987 Great Storm and, more recently, the St Jude storm.

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

october extremes

October SJP

Heathrow oct

Some national UK October values according to TORRO

Hottest: 29.4C March, Cambs – 1st 1985
Coldest: -11C Dalwhinnie 28th 1948
Wettest: 208.3mm Loch Avoich 11th 1916

In terms of climatology October maxima, considering the 1981-2010 average, shows a through the month, though around there is often a spike. This would reflect the October singularities; early October storms, between 5th and 12th, peaking on the 9th, occur in 67 per cent of years. St Luke’s summer, between 16th and 20th, peaking on 19th, also has a 67 per cent probability. If you look at the graph there is a spike just after the 19th.
Mid-autumn storms occur between 24th and 29th October, with a 100% probability.

october average graph

The average rainfall graphic shows that downpour amounts are variable through the month. A tendency for dry weather around the 17th and 18th before the wettest days on the 20th and 21st.

October rainfall

 

 

 

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

The disappearing street trees of Wanstead

Street trees around Wanstead and the surrounding area have been disappearing at an alarming rate over the last few years. But it is not just the council’s technical policy of removing mature specimens that is to blame.

Changing rainfall patterns and poor husbandry have both contributed to the loss of some of the magnificent trees that once graced our roads and avenues.

A huge horse chestnut that once stood outside Wanstead High School first showed signs of distress in 2011. By 2017 it was completely dead and has since been chopped down.

One of the large limes on St Mary’s Avenue was a picture of health in 2015 but within two years it was completely dead and has also since been chopped down.

A huge old beech in the front garden of a property in Blake Hall Road was showing signs of distress in 2017 and came crashing down in 60mph winds from Storm Fion in January 2018.

Yet another huge old beech that stood proud in a front garden of St Mary’s Avenue has been dying since 2012. The second image reveals very thin foliage in summer 2017. The tree was chopped down a couple of weeks ago as it was clearly dead and posed an obvious safety risk, given what happened to the beech in Blake Hall Road in January this year.

The mature trees of Christchurch Green took a real hammering during the St Jude Storm in October 2013, among those lost were three gorgeous old limes. New trees have been planted but they will take decades to match the size of those lost.

Of course the loss of these trees and other could be attributed to bad luck and coincidence that many are reaching the end of their lives at the same time.

As a country we get a bit hung up on cutting trees down – in the near continent they are much more pragmatic and proactive through planning over a period of years in getting trees in the ground. So that when trees do die there’s not such a huge gap left in roads and parks.

On tree basesaying this there also needs to be more joined up thinking by councils in terms of looking after the existing tree stock. Far too many trees suffer because contractors are inconsistent with road and pavement repairs. Ideally the base of trees should have space for mulch to be applied but, too often, Tarmac is applied right up to the base.

Have you noticed mature trees dying suddenly recently? Please reply to this blog and I will add them.

 

The disappearing deluges of September

While putting together my September extremes blog I noticed that the month was marked by some big rainfall episodes. On a national scale TORRO statistics show that a south-east climate station holds the daily record for September – unusual in that every other month is dominated by stations in the north and west of Britain.

Further analysis of local data since 1959 shows how September has slowly evolved from being dominated by autumnal to summery weather. The wettest period, from the mid Sixties to the mid Seventies, saw 42 per cent of highest daily rainfall events recorded.

Two of these events, in 1968 and 1973, are well noted and appear in RMET’s Weather magazine.

1968

In Wanstead, between 14th and 15th September, a total of 58.4mm fell, a large total though far less than elsewhere.

The rain became torrential overnight in southeast England and continued through most of the 15th. Rainfall totals ranged from three inches in the London area and nearly four inches in southern Essex to approach the quite abnormal level of nearly seven and a half inches in parts of Kent during the 14th/15th.

The area of greatest precipitation was near the Kent, Surrey and Sussex border where violent downpours in the 12 to 15 hour period from midnight on Saturday to the early afternoon of Sunday 15th led to widespread and disastrous flooding. The heavier rain area moved north and east during the night of 15th/16th and Gorleston recorded.

The highest accepted two-day falls were 201mm at two rain gauges at Tilbury
and Stifford in Essex, and a similar fall north of Petworth in Sussex. The highest ‘rainday’
totals (i.e. nominally 0900–0900 GMT) listed in British Rainfall 1968 were 129 mm at
Bromley and 125 mm at South Godstone sewage works in Kent, both on 15
September.

This exceptional event was described by Bleasdale (1974), Salter and
Richards (1974) and Jackson (1977) and the map below (Fig. 1) is taken from Bleasdale’s
paper in British Rainfall 1968 (p. 231). In all, some 575 km2 received more than 150 mm
in 48 hours.

1968 rainfall

1973

In Wanstead, on 20th, a total of 55.4mm fell, the largest daily total recorded in September. Again it was far less than elsewhere.

5pm gmt 20th 1973

There were notable falls of rain in London, Surrey, West and East Sussex, and particularly Kent. At Manston, near Margate, 172 mm fell in 18 hours 40 minutes commencing 1710 GMT; at nearby West Stourmouth 190.7 mm fell in the rainfall day i.e. the 24 hours commencing 0900 GMT on 20 September (source: Met Office internal list of heavy falls of rainfall in short periods in the United Kingdom during the year 1973; Rainfall/heavy falls section listing, available in manuscript/computer printout form in Met Office archives).

The future

Big September rainfall events seem to be becoming rarer in our part of the UK, the last was in 2014, on the day of the Scottish referendum, though this was convective rather than frontal rainfall.

The outlook for the rest of this month suggests yet another absence of a large rainfall event. The ingredients for large rainfall totals in the south-east – blocking high to the north with slow moving low pressure over Brittany – look unlikely to form during the remainder of the month. We probably will see rain but any fronts are likely to move through quickly, with typical totals being around 5mm.

rain rest.gif

When did September become a summer month?

The answer is around 1993. A look back at mean temperature and rainfall statistics for east London over the past hundred years reveals that the ninth month has, since that date, slowly become warmer and drier.

Putting all the arguments of meteorological and astronomical summer aside, many people of a certain age regard September as an autumnal month, but as recent years have shown it can very often be an extension of summer; September 2016 was the second warmest on record in the local area, warmer than many previous summer months!

Looking back even further, over the past 100 years, the September mean has trended upward, though many peaks and troughs reveal how the month has ebbed and flowed from being summery to autumnal.

The prognosis to the end of this month suggests that air pressure will be anomalously high – so the pattern in the south-east for settled, summery weather in September doesn’t look like ending any time soon.

sept means
The September mean trend has crept generally upward.
sept rainfall
A look at rainfall back over the last 100 years shows that wet Septembers have been on a general decline since 1994.

sept chart.gif

Climbing the 3,200m Jegihorn

Four months on from an amazing ski tour I was back in the Swiss Alps in August, this time for a week of mountaineering and rock climbing.

The (mostly) white wonderland of April had transformed into the deep green of summer in the valley, the temperature on my arrival in Visp was a hot 30C. Waiting patiently was my guide, Davide, and we were soon on our way to the cooler climes of Saas Grund, little sister to Saas Fee – though with scenery as, if not more, spectacular.

weissmeis
The glacier leading up to the 4,017m Weissmies stops abruptly around 3,000m

Day 1: Jagihorn from Hohsaas hut

Mountain sickness saw me abandon any attempt of climbing the Weissmeis. Though sleeping at the the Hohsaas hut was intended to help me acclimatize to the altitude I think the 3,100m elevation was simply too much for my system to handle. It is hard to put into words the symptoms; imagine your worst-ever hangover and multiply it by five.

hohsaas
The Hohsaas hut, left, and cable car

Anyone can get sudden altitude sickness, even top athletes. After an awful night I was ready to descend back to Saas Grund but was soon sent back to bed with a painkiller. Two hours later I was just about fit to set off and was soon descending down the valley to climb the 3,200m Jegihorn in the far distance. I felt a pang of disappointment as I glanced over my shoulder at the magnificent Weissmeis; the purpose of the week was to get as much glacier mountaineering as possible.

 

jegihorn distance
The Jegihorn can be seen in the distance

As we traversed over the scree and across gurgling streams however, the beauty made me forget my disappointment. The sheer magnificence of the Jegihorn soon became apparent, too. It reminded me of Tryfan in Snowdonia, only this was three times the size.

The route up soon forked – it was either the ‘easy’ way up or via ferrata, a series of steep drop offs, grab handles, steps and precarious looking ladders allowing access up sheer cliffs. After a couple of hours progress to the peak proper becomes a choice of climbing down and up or this suspension bridge that is like something out of the film Cliffhanger.

bridge
This suspension bridge, high above a ravine, saves the pain of walking down and up to the summit proper.
bridge me
Like something out of the film Cliffhanger

After the bridge it is a further scramble up steep ledges and narrow gullies for the remaining couple of hundred metres to the summit.

summit marker
The summit of the Jegihorn with Saas Fee in the far distance
summit me
The 3,206m Jegihorn using the via ferrata route up

With every summit comes a descent, the part I always find the hardest because of the strain on the knees. But the trek back to the bottom of the Hohsaas cableway presented plenty of scenery.

blue lake
A solitary cloud hangs above a aquamarine mountain lake
grey glacier
The rugged and harsh glacial landscape, shaped over millions of years
boulders
The landscape on the way down from the Jegihorn shows all the signs of movement that comes with time
marmotte
I saw about 5 marmottes on the descent. You can see one under the rock if you look closely

 

 

 

 

UFO flies by the Shard

I often look at the excellent webcams of London site to help me decipher cloud types and amounts for my 9am GMT observation. This evening I discovered that the timelapse of the last 24 hours included a very interesting white light floating past the Shard.

At limited resolution it is difficult to see what the object is. My suspicions that a UFO had been captured were quickly shot down with the help of Twitter including the excellent 

My UFO was the Moon!

London’s September extremes since 1959

September in recent years has often been a more summery month than August. But this month in some years can see a rapid onset of autumn.

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

september extremes

SJP september

heathrow sept

Some national UK September values according to TORRO

Hottest: 35.6C Bawtry, South Yorkshire – 2nd 1906
Coldest: -4.5C Dalwhinnie, Highland, – 26th 1942
Wettest: 190.7mm West Stourmouth, Kent – 20th 1973

In terms of climatology September maxima, considering the 1981-2010 average, shows a slight decrease through the month, though around the 1st and the 22nd there is often a spike. This would reflect the September singularities; early September warmth occurs in 82 per cent of years while the ‘Old Wives Summer’ has a 64 per cent probability.

september mean

 

The average rainfall graphic shows that downpour amounts are variable through the month. A tendency for dry weather to the 8th prevails before the trend increases, the wettest days usually 13th and 19th.

sept rain

 

 

Meteorology-based musings about east London and beyond

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