April 2014: Another mild and dry month

April 2014 continued this year’s theme of being milder than normal; the mean temperature of 12C was 2.2C above average, making it the third warmest April since 1797.

Though many days were stunningly sunny the breeze made it feel chilly
Though many days were stunningly sunny the breeze made it feel chilly

April continued the dry theme of March and was indeed dryer on average. Just 19.6mm on rain fell over the 30 days – that’s 46 per cent of average.

The month saw some stunningly sunny days during the second week into the third week, though these were tempered by chilly east to north-easterly winds. The warmest day was the 21st when 21.5C was reached – the first ^70F temperature of the year.

Though it ‘felt’ quite a sunny month the 150 hours recorded was only 94 per cent of average.

Some nights were chilly when the sky cleared but there was no air frost and only two ground frosts, on the 15th and 16th

To view full stats follow this link:http://1drv.ms/1cBRoH3

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If the oak before the ash…

…then we’ll only see a splash. If the ash before the oak then we’re sure to get a soak.

If this old weather saying carries any weight then this summer should be a corker…

This young ash on the corner of Montalt Road and Chingford Lane, Woodford Green, is much later into leaf than the adjacent oak
This young ash on the corner of Montalt Road and Chingford Lane, Woodford Green, is much later into leaf than the adjacent oak

Only I wonder how many of the ash trees I noticed on my ride back from Enfield this afternoon are struggling to survive let alone burst into leaf. The initial onset of chalara fraxinea (ash dieback) over the past couple of years now seems to be taking its toll in a much bigger way on ash specimens around the countryside.

The tell tale dead branches are becoming a lot more common.

Some have blamed the spread of Chalara on cheap imports of ash trees from Holland – the first cases were confirmed in a nursery in Bucks early in 2012. Efforts were made to find and contain affected specimens but, throughout East Anglia and the South East, the disease seems out of control.  It could be only a matter of time before the disease scars the landscape with dead trees in the same way that Dutch Elm Disease did in the 1970s.

From one poor management of trees to another – namely the ultra harsh pollarding of the London planes in Wanstead High Street. Whilst this style of management is nothing new and seems to be de rigeur among most London councils it does nothing for the scene of many roads and streets through the capital. What was once a rich canopy of green providing shady relief from the sun during high summer is just a few stumps. It takes a good few years for the canopies to regenerate – by which time it’s time for another visit from the tree surgeons…

Plane ugly: the harshly pollard planes in Wanstead High Street
Plane ugly: the harshly pollarded planes in Wanstead High Street

To blame, partly, is the spread of another tree pest – Massaria. This unseen pest ‘eats’ away the tops of branches – compromising the strength of the wood eventually to the point where, if unchecked, the whole limb comes crashing to the ground. London plane is very heavy wood – with branches weighing dozens of kilos there’s obviously safety issues with limbs dropping on peoples’ heads.

Though councils would argue otherwise I think the harsh pollarding is a cost saving measure – without this they would have the added cost of constant monitoring.

The fast-growing, non-native London plane was planted on the understanding that growth would be carefully managed and limited in height. But looking at some of the monster specimens around the capital that seems to have gone by the wayside a long time ago.

The City of London Corporation is well aware of the problem and is closely monitoring the capital’s stock.

If you have magnificent London plane near you make the most of it – the buzz of the tree surgeons’ chainsaws are getting closer.

 

 

Kop this for a singularity

The last time Liverpool won the league in 1990 (by league I mean top tier of English football) the South East enjoyed a mostly dry, warm and sunny summer. A particularly hot spell in August of that year saw the UK high temperature record broken when the mercury reached 37.1C at Cheltenham on August 3rd, a record that stood until 2003.

Since the middle of December last year the weather has been remarkably similar to that football season when the Reds won their 18th league title. Both winters were remarkably mild and stormy with January 1990 seeing the Burns’ Day storm.

90 - 14

The mean temperature this year over the same period, December 13th to April 26th, is just 0.2C cooler than 1989-90, while rainfall is 2.1% greater and sunshine is 2.5% less. A remarkable singularity.

Will history repeat itself come the end of the season and the end of the summer? Up until early Sunday afternoon the stage seemed set. But a slip by Liverpool skipper Steven Gerrard at the end of the first half gifted Demba Ba with a chance that opened the way for Chelsea to complete the double over their title rivals.

LiverpoolSquad1989-1990
The Liverpool squad of the 1989-1990 season won the club’s 18th league title

It must have been agonising for the Kop to watch, 24 years on from the exact same weekend the Reds lifted the title with two games left. The weather that followed that memorable day was dry, sunny and warm with temperatures reaching the mid 20s on many days.

Fast forward two dozen years and the weather looks decidedly unsettled, with frequent showers or longer spells of rain interspersed with sunshine. Though there’s doubtless many twists and turns left I wonder if Reds fans believe their title hopes are going the same way as the change in the weather?

Football’s a funny old game – just like the weather.

March 2014: Mild, dry and sunny

March 2014 will be most remembered for glorious sunny days that brought welcome relief after a run of seemingly endless wet months.

Pear blossom by Scott Whitehead
Many trees blossomed early this year, thanks to the mild winter

It also continued the mild theme of the winter; the mean temperature of 9.1C was 1.4C above average, making  it the 11th warmest March since 1797. Looking at my other series back to 1881 the March mean maximum was second only to March 1938!

Just 25.8mm of rain fell over the 31 days – that’s 63 per cent of average.

The month started on the chilly side but with plenty of sun around it felt pleasant. Though many days were warm clear skies led to frost and fog forming. Hail was observed on three days. 

The most notable weather occured on the 26th when the temperature fell from 10C at 1.30pm to 4C by 3pm. Heavy showers accompanied what was an utterly foul day. The cold pool persisted into the 27th with towering thunder clouds surrounding Wanstead, north, east and south – with reports of hail in Berkshire and snow in Folkestone.

The month ended with warm, sunny weather – the southerly flow bringing Saharan dust that deposited on cars. There were 4 air frosts  and 14 ground frosts.

Saharan dust fall on car, by Scott Whitehead
A southerly airstream brought dust that originated from the Sahara Desert

To view full stats follow this link: http://1drv.ms/1cBRoH3

 

An unprecedented climate of confusing stats

‘Worst-ever!’, ‘in living memory’, ‘highest on record!’, ‘unprecedented!’. These phrases, used often by newsreaders on the main networks including Sky and BBC, always set an alarm bell ringing in my head. None more so than weather stories which, with the stormy winter we’ve just had, has been happening almost daily since the middle of December.

Screen shot 2014-03-01 at 02.48.32As the winter has progressed the networks have tried to out do one another with the severity-value of a story. What starts with a reporter gingerly standing by the side of a flooded field within days changes to the reporter, donning a pair of fisherman’s waders, trawling waist-deep through a flooded Berkshire housing estate.

The media also seem to delight in rushing out Met Office data to proclaim these armageddon scenarios before the season is over and the statistics can be properly studied, absorbed and commented upon.

Last summer, I started to build a dataset for my own area – Wanstead. Using local figures from the City of London Cemetery I was able to take the daily series back to 1959. Beyond this I then sourced monthly data for Greenwich, 6 miles away, back to 1881. Using W.A.L Marshall’s A Century of London Weather and Luke Howard’s The Climate of London enabled me to take the series right back to 1797.

The series makes for interesting reading, putting this winter as 6th wettest since 1797. Scientists would say that because my series is only one dataset it cannot be regarded as a ‘catch-all’ for the country overall. But when statements like “England and Wales has had its heaviest rainfall since 1766” are put out by the media it is blatantly not true for the entire country. Just a quick look at the map shows that while parts of south and southeast England have been very wet – other parts of the country have been much less so.

But in this age of 24-hour rolling news the message to anyone who takes the headlines at face value is that this has been the wettest winter ever. You can view the winter mean temperature and rainfall stats here.

winter rainfall

mean temp winter

Air frost free February 2014

Although February was wet it was relatively much dryer than January and calmer than the other two months. February often brings us our best snowfalls and coldest weather but this was completely absent this year, continuing the theme of a snowless December and January.

Wanstead Flats by Scott Whitehead
The water table appears to have come to the surface on Wanstead Flats

Some 69.9mm of rain (178% of average) fell in February – the wettest since 2010 – and 32nd wettest in the series back to 1797.

February was also warmer than average with a mean temperature of 7.5C (2.2C above the 30-year average) – ranking it 13th in the series since 1797 – and the warmest January since 2011. Though the month was very mild no single day was particularly mild. Highest maximum was 14.5C on the 24th.

The most notable day was a storm on the evening of Valentine’s Day into the 15th which saw yet more damage, resulting in two deaths including a man killed by a wave on a cruise ship in the Channel. A woman was killed when a 3ft by 3ft block of falling masonry crushed her car outside Holborn station.

Air frosts: 0 – very unusual for February

Ground frosts: 7

To view full stats follow this link: http://1drv.ms/1cBRoH3

A wet winter, but no record breaker

Rain, rain and more rain. Winter 2013/14 will be most remembered for its incessant precipitation that brought flooding to many parts of the country including the Somerset Levels and many towns and villages along the Thames. But, in this locality, it was no record breaker – being only the 6th wettest in my series going back to 1797. The mean temperature of 6.7C made it the 10th mildest, a full degree colder than the warmest winter of 1989/90.

Wanstead Flats by Scott Whitehead
The water table appears to have come to the surface on Wanstead Flats

The winter was notable for its complete lack of lying and falling snow. Indeed NO snow falling was observed for the entire three months – something that hasn’t happened in this area in at least 50 years – possibly longer. There’s still a chance of snowfall before April’s out – the snowfall season can last from November to May – but with the increasing strength of the sun any snow cover will be short-lived.

The opening few days of December were calm and quiet but a storm on 5th caused two deaths and much damage in the north; a tidal surge in the North Sea brought flooding along the east coast. The coldest spell of the winter arrived the second week of December with fog and a couple of frosts. From the 15th, however, the Atlantic cranked into life and pretty much drove the weather for the whole winter. A strong jetstream stayed over or very close to the UK for much of the three months, driving depression after depression over the British Isles.

Though daily totals were not record-breaking it was noticeable how much heavier the rain was at times across the Thames. A storm that ran from December 23rd into Christmas Eve brought 23.4mm of rain to Wanstead while at Kenley, 17.5 miles away, over four times as much was recorded. The intense streamer of rain and high winds brought power cuts to Gatwick airport, delaying thousands of travellers on their way home for Christmas. Five people were killed as a result of the storm.

Tree damage by the war memorial in Wanstead High Street by Scott Whitehead
Damaging gusts associated with the depression on December 23rd felled this tree by the war memorial in Wanstead High Street

The wet theme continued through January with added thunder and lightning. The most notable day was Saturday 25th when what started as a bright, fine day quickly changed around 4pm as a strong squall with heavy rain blew through with associated thunder and lightning and 6C fall in temperature in an hour. Wanstead escaped the damage of elsewhere. Numerous trees blocked rail lines in Kent and gusts of over 60mph were widely reported.

There were two other incidents of thunder and lightning on 5th and 6th – very unusual in the middle of winter and an average normally observed in high summer.

Yet more rain greeted the month of February though things turned somewhat dryer after 15th, though rainfall for this month was still over 180% of normal. A storm on the evening of Valentine’s Day into 15th saw yet more damage, resulting in two deaths including a man killed by a wave on a cruise ship in the Channel. A woman was killed when a 3ft by 3ft block of falling masonry crushed her car outside Holborn station.

A few stats:

Air frosts: 10

Ground frosts: 29

Warmest day: 14.5C (24/2)

Coldest day: 4.2 (12/12)

Coldest night: -2.9 (11/1)

Warmest night: 8.9 (6/1)

Wettest days: 23.4mm (23/12) 16.2mm (28/1) 14.6mm (16/1)

Highest gust: 31.1mph (16/12, 5/1)

Windiest day: January 5th

Full details can be viewed here: http://1drv.ms/1d3JK8J

When the River Lea was a mile wide

Floods in Somerset have, up to now, seemed far removed from our own back yard. But with thousands of homes by the upper parts of the River Thames now at risk of flooding I wondered how safe we were from our own rivers.

A look back through the reference books show the geography of the Roding and Lea Valleys has made the area prone to inundations for hundreds of years.

The Environment Agency's Flood Map for Planning shows the flood zone risk of the area. And endorses Howard's account that the river Lea was 'a mile wide' at its peak
The Environment Agency’s Flood Map for Planning shows the flood zone risk of the area. And endorses Howard’s account that the river Lea was ‘a mile wide’ at its peak

In January 1809 the lower River Lea burst its banks in several places following a deluge that dumped two inches of rain in the space of 24 hours. The rain abruptly ended a snowy cold spell that had begun over a month before in the middle of December. From Luke Howard’s readings it is likely that up to half a metre of snow had fallen in the previous weeks in the upper parts of the surrounding countryside with only slight thawing. With the frozen ground unable to absorb any of the rapidly melting snow and rainfall the amount of water flowing downstream must have been immense. Howard takes up the story…

“The River Lea continued rising the whole of the 26th… The various channels by which it intersects this part of the country were united in one current above a mile in width which flowed with great impetuosity and did much damage.”

Howard, his chemical factory located on the banks of the river Lea close to what is now Bow flyover, wrote at length about the event, his account replacing the usual brief notes about daily weather in his book The Climate of London.

He talks of embanked pasture land being “filled to the depth of eight or nine feet” and people driven to their upper rooms relieved by boats plying under the windows.

The Environment Agency's Flood Plan map of the Thames illustrates Howard's comment that "the Thames was so full during this time that no tide was perceptible"
The Environment Agency’s Flood Plan map of the Thames illustrates Howard’s comment that “the Thames was so full during this time that no tide was perceptible”

“The Thames was so full during this time that no tide was perceptible.” It took until February 23rd for things to return to normal.

Miraculously no lives were lost in the flood and cattle “by great exertions” were saved by being kept in their stalls. Howard, saying that the flood could have been far worse, believed a neap tide, strong westerly winds urging water down the Thames and mild weather helped avert a tragedy.

Howard’s statistics of the previous months show that the second half of 1808 were wetter than average – though not especially so. And nothing like the rainfall we have had this winter. From December 1st until February 8th Howard recorded 130mm of rain, which is about 100mm less than what I have recorded this winter.

This fact alone shows just how much the nature of the river has changed in the last 200-odd years thanks to spending on flood defences.

Work to improve the defences was prompted 67 years ago when similar catastrophic flooding came with the thaw that ended the severe winter of 1947, one of the coldest winters in recorded history and an episode remarkably similar to what Howard recorded in 1809.

Wanstead
Flood risk areas around the River Roding close to Wanstead are much smaller than the equivalent area in Lea Valley

The Lea Valley, along with many parts of the country, saw some of its worst flooding in a generation. The river burst its banks at several points bringing misery to surrounding communities. Valleys turned into lakes in 40 counties and East Anglia’s fens were a sandbagged inland sea. More than 100,000 properties were damaged and, then as now, heroic battles were fought by the military to keep water-pumping plants and power stations dry.

The sense of crisis was felt worldwide. Canada sent food parcels to stricken villages in Suffolk; the prime minister of Ontario even offered to help dish them out.

A marker of that flood, together with a history of flood defences, can be found here. There is also British Pathe footage of another flood between 1910 and 1919 here .

The River Lea Flood Relief Channel, that flows between Ware, Herts, and Stratford, took almost three decades to complete. The channel incorporates existing watercourses, lakes and new channels. Since it was completed in 1976, there have been no major flood events in the Lea Valley, although there have been three occasions when the river system was full virtually to its capacity: in 1987, 1993 and 2000. Since its completion, the level of protection afforded by the structure has declined, so that in some areas it offers 2 per cent protection, and in some, only 5 per cent protection. The Environment Agency published a strategic environmental assessment in 2008, which looked at ways to maintain the flood defences in the Lea Valley.

Wanstead Flats by Scott Whitehead
The water table appears to have come to the surface on Wanstead Flats

It remains to be seen whether we will see any flooding in Redbridge – a further 40mm of rain is forecast to fall up to Saturday morning. As well as the problem of rain there is also the issue of the water table which in the past week has risen to the surface in places. Inland lakes forming on Wanstead Flats have seen the cancellation of  football fixtures and a couple of people I’ve spoken to say standing water has started to appear in their cellars

It is all too easy to blame the Environment Agency for the current flooding in Somerset and elsewhere but the meticulous planning by its forerunners brought, at least to date, an end to the widespread flooding problem in the Lea Valley.

As the government struggles to find a solution to the current problems with flooding it would do well to look to the grand schemes of the past and forget about any planned cuts to flood defences.

This wet winter is by no means unique

With flooding in the Somerset Levels dominating the headlines it is easy to get carried away with media hysteria that we are in unprecedented times in terms of rainfall. But as with so many media stories these days you don’t have to look far back in meteorological records to find that we’ve been here before.

The jetstream has been virtually ever present over the UK this winter, driving depression after depression over our isles
The jetstream has been virtually ever present over the UK this winter, driving depression after depression over our isles

Although I base this blog on local figures – two series of stats going back to 1881 and 1959 – it is notable that this particular microclimate has actually been dryer than neighbouring areas, including east Essex where the rain crossing this area often peters out. With such power in the jet stream, however, bands of rain have been pushing right through this winter. Surrey has also been notably wetter, with orographic uplift only partly responsible for the increased wetness. Anyone driving around the M25 will have noticed the flooded fields at the side of the motorway.

It has been mentioned that this winter has been the most cyclonic in recent memory, but you only have to go back to the winter of 2000-01 to find a more cyclonic winter, though that season saw fewer severe gales.

Since the beginning of the meteorological winter on December 1st Wanstead has recorded 235.6mm of rain to February 6th. Considering the 1959 series that’s 7% wetter than the winter of 1989/90 – though this winter is actually 0.9C colder than that season 24 years ago.

Looking at the bigger picture, and with 22 days to go, this winter is currently 7th wettest in the series going back to 1881 – quite a way behind 1915 which saw 343.7mm recorded. Looking at the GFS model out to 9 days, however, there is much more rain to come.

The season so far, in terms of temperature and rainfall, has been notable in that autumn did not really offer any hints as to how winter would unfold. At the beginning of December I would have put the probability of a winter such as we have had so far at 10%. Should the rain continue to fall while the temperature stays mild the probability would fall to 1% – a truly exceptional winter in the same league as 1962/63 – but at the other end of the scale.

After my less than impressive stab at a winter forecast I am a bit loathe to make any more predictions. Trying to predict the weather more than a few days ahead with any detail is impossible. And seasonal forecasting is fraught with difficulty. However, precedent suggests we could be in for a warm and settled March. Indeed, if this year is anything like what followed in 1990 we could be in for a very nice summer. But then again we might not. As Mark Twain said: ‘Climate is what we expect; weather is what we get’.

January 2014 wettest for over 130 years

The last time January was so wet Eddie ‘The Eagle’ Edwards was about to fly the flag for Great Britain in the ski jump at the Winter Olympics in Calgary, Canada, in 1988.

There was occasional respite from the persistent rain
There was occasional respite from the persistent rain

Some 130.6mm of rain (251% of average) fell in January, beating the previous record set in 1988 by just 2.8mm around midnight on Saturday 1st. Unlike 1988, last month followed a December that was 154% wetter than average. The wet spell, which started on December 13th, is only now making a real impact on the river Roding which is now running very high.

January was also warmer than average with a mean temperature of 6.4C (1.5C above the 30-year average) – ranking it 20th in the series since 1881 – and the warmest January since 2008. Though the month was very mild no single day was particularly mild. Highest maximum was 12.7C on the 7th.

The most notable day was probably Saturday 25th when what started as a bright, fine day quickly changed around 4pm as a strong squall with heavy rain blew through with associated thunder and lightning and 6C fall in temperature in an hour. Wanstead escaped the damage of elsewhere. Numerous trees blocked rail lines in Kent and gusts of over 60mph were widely reported.

There were two other incidents of thunder and lightning on 5th and 6th – very unusual in the middle of winter and an average normally observed in high summer.

Air frosts: 5 : coldest night of winter so far was observed on morning of 12th with -2.9C

Ground frosts: 11

Meteorology-based musings about east London and beyond

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