Weather Eye

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June 1, 2004

BY PAUL SIMONS

COULD Britain be plunged into an ice age by the collapse of the Gulf Stream, as the film The Day After Tomorrow suggests?

The idea is not new: it was first floated in 1855 by an American naval lieutenant, Matthew Maury, the most famous oceanographer of his time. Maury spent years gathering ships’ log books to compile a global picture of wind and currents.

He showed that the Gulf Stream channeled heat from the tropics to Western Europe and added a chilling warning that without the Gulf Stream “the soft climates of both France and England would be as that of Labrador, severe in the extreme, and ice-bound”.

But were we hoodwinked by Maury? Last year scientists claimed that the Gulf Stream adds little to Britain’s mild climate. Using 50 years of weather data and a powerful computer model, they showed that the North Atlantic soaks up enough heat to keep Britain warm in winter like a huge radiator.

The Rockies also help, by sending westerly winds off course and shooting warm southwesterlies across the Atlantic and over Britain.

Link to Weather Eye source

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June 2, 2004

BY PAUL SIMONS

A good leak in June

Sets all in tune

THE month got off to a soggy start yesterday in many places, thanks to a miserable Atlantic weather front.

As expected, the band of rain nudged into the South West on Monday. It had been forecast to make a mess of the Bank Holiday across the rest of the country but it stalled, leaving glorious weather over much of Britain and many forecasters with red faces.

June is a fickle month which can throw up all sorts of wild weather, from floods to snow, heatwaves to thunderstorms, making a nerve-racking time for Royal Ascot, the Test matches, Henley and Wimbledon.

What we are seeing now is a shift away from cold northerly winds that sent a chill through May and the return of rain-bearing westerlies. This shift to wetter weather often swings into force around mid-June and is called the “return of the westerlies”, or even the “June monsoon”.

However, the rainclouds also jostle for position with the Azores High, bringing hot and sunny weather, which is expected over the southern half of Britain this week.

Link to Weather Eye source

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June 3, 2004

BY PAUL SIMONS

TEN years ago, an RAF Chinook helicopter crashed on the Mull of Kintyre, Scotland, killing 29 people. It was the largest peacetime tragedy that the RAF has suffered. The blame for the accident was put on pilot error, but John Major, who was Prime Minister at the time, has called for the pilots to be absolved (The Times, May 13).

Dr Alan Gadian, an atmospheric physicist at the University of Leeds, believes that the crash may have been caused by an unusual form of air turbulence. Usually the atmosphere grows colder the higher an aircraft flies, but sometimes a layer of warm air sits on top of a cold layer — what is called a temperature inversion.

That trapped cold air can drive down the side of a hill and create violent eddies causing powerful wind shear — a sudden change in wind speed and direction. Pilots get no warning of these sharp wind shifts and aircraft can stall, which is a particularly serious problem for slow-moving aircraft or helicopters.

Dr Gadian said: “If you hit one of these patches, you get very sharp shear and you will drop down. There’s nothing you can do about it.”

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June 5, 2004

BY PAUL SIMONS

I WAS listening to a radio programme about the lengths that people go to to avoid lightning strikes indoors.

One person would put away all cutlery when thunder was heard. Another confessed to covering mirrors, for no obvious reason, and fireplaces were boarded up to stop ball lightning coming down chimneys. One dangerous idea was to open outside doors. This could allow lightning to strike inside.

But it is true that unplugging TV sets and computers helps to protect them. Every year dozens of TVs are blasted inside homes by lightning hitting outside aerials, and computers are particularly vulnerable to lightning-induced power surges through modems or power lines — a brutal lightning strike this year in Brecon town centre fried almost all the computers there. It is worth unplugging computers not in use or adding a power surge protector.

Even making a phone call in a thunderstorm can be risky. Several people are struck by lightning each year using a phone connected to outdoor lines. It is a myth that using a mobile phone attracts lightning but do not stand near a mobile phone mast in a thunderstorm.

Link to Weather Eye source

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June 7, 2004

BY PAUL SIMONS

THE transit of Venus across the face of the Sun tomorrow will give a rare chance to study the planet’s weather.

The climate of Venus is a greenhouse effect gone mad. Its atmosphere is thick with carbon dioxide which traps the Sun’s energy, making Venus the hottest planet in the solar system: about 500C (900F).

But we know little about the planet’s upper atmosphere. As Venus passes across the Sun it is hoped to get a peep into this region using a special telescope which can measure the spectrum of sunlight as it shines through the atmosphere above the planet’s layer of thick, acidic clouds.

As different wavelengths of light are absorbed in this atmosphere they should reveal different gases; the way the gases move will give clues to the wind patterns.

In another study, astronomers at the European Space Agency will watch the transit of Venus for a tiny dimming of the Sun’s intensity — only about 0.0076 per cent change in brightness. Similar dips in the brightness of stars outside our solar system may help the hunt for new planets that can be detected by sensitive orbiting telescopes.

Link to Weather Eye source

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June 8, 2004

BY PAUL SIMONS

BECAUSE the Germans lacked information from the Atlantic, they failed to spot a lull in the storms in the Channel on D-Day. That was partly because of a battle being waged in Greenland.

To forecast weather for Western Europe, it is crucial to get observations from Greenland, and the Germans repeatedly tried throughout the war to set up weather stations there.

In appalling cold, storms, blizzards and icebergs, the US Coast Guard searched for the enemy, capturing several German ships en route to Greenland with weather teams. Greenland also established its own army of 26 men, the smallest army in the war, and patrolled its coastline with sledges.

In the spring of 1943, a patrol encountered a German weather team and captured a German offi-cer, who was taken on a month-long journey of 300 miles over ice and delivered into US hands.

A few weeks before D-Day, a sledge patrol found a German weather station on a remote island and in an intense battle killed the German commander and destroyed the operation. For the rest of the war, the Germans had to use vastly inferior automatic buoys and automatic weather stations.

Link to Weather Eye source

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June 9, 2004

BY PAUL SIMONS

LICHENS are a strange life form, a marriage of algae (or bacteria) and fungi, often looking like crusty splodges stuck on stones or trees.

Because lichens absorb minerals and water from the air, they are acutely sensitive to air pollution, which is why many flourish in the clean mountain air of the Scottish Highlands.

But four species of lichens there have become extinct recently, and the blame is being pinned on Scotland’s rising temperatures. The four lichens all come from high mountains where temperatures are usually cool.

For instance, Bellemerea alpina, which is found nowhere else in the world, is a yellow-white lichen that used to grow on pebbles near a stream just below the permanent snow on Cairn Gorm mountain. But last year was the warmest on record in Scotland and the summer’s heatwave melted all the snow — only the fourth time that this has happened in history.

The alpine lichens simply cannot cope with that sort of heat.

More species of lichens and plants are at risk as the warming climate pushes their semi-Arctic habitats further north or up to higher ground.

Link to Weather Eye source

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June 10, 2004

BY PAUL SIMONS

THE England football squad would have done well to acclimatise at home rather than Portugal on Tuesday, when temperatures in London soared to 31.4C (88.5F) compared with Lisbon at 29C (84F).

The heat came from an anticyclone sitting over Europe and sweeping in hot air across the Channel, making the East and South especially hot.

Temperatures would have climbed even higher had it not been for high-level clouds swept up from the Bay of Biscay, veiling the mid-afternoon sun and cooling things down somewhat.

Of course, heatwaves in June are not unusual: June has scored the hottest temperature of the year 22 times in the past 100 years. But it is unusual to hit 30C so early in the month, although the hottest June 8 was in 1915, when Cromer, Norfolk, hit 32.2C (90F), which was also the highest temperature of that year.

June can be very fickle, though, none more so than in 1975 when a cricket match in Buxton between Derbyshire and Lancashire on June 2 was abandoned when snow stopped play. But a few days later, a heatwave started an exceedingly hot summer.

Link to Weather Eye source

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June 11, 2004

BY PAUL SIMONS

BRITAIN could well be the Tornado Alley of the world, with more tornados per acre than the rest of Europe and the US.

According to scientists at the University of Leeds, about 100 tornados strike us each year. Although only about 30 of those are reported, many more go unreported because they hit rural areas where there are no witnesses or they are too small for most people to recognise.

The estimation was made by detailing past tornados and creating a model of the conditions that spawned them. The model then pinpointed the weather when tornados would most likely happen.

Torro, the Tornado and Storm Research Organisation, says Britain is prone to tornados partly because of our large number of depressions, where cold fronts racing in off the Atlantic undercut hot air, creating unstable conditions needed for tornado formation. Tornados are the fastest winds known on Earth, reaching a record 509km/h (318mph) in Oklahoma City on May 3, 1999. Our tornados tend to be less powerful — few reach 160km/h, they generally move less than a few miles overland and usually last only a few minutes.

Link to Weather Eye source

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June 12, 2004

BY PAUL SIMONS

FIFTY years ago Sylvia Mowday took her young son and daughter to see a naval exhibition at a park in Sutton Coldfield, near Birmingham.

The day was overcast, but suddenly the sky became dark, rain pelted down and everyone, including the Mowdays, ran for shelter. Then they saw something unbelievable: as the rain fell in torrents, thousands of tiny thumbnail-size frogs showered down all around them.

“I thought it was hail, but my son suddenly said ‘It isn’t hail, Mum, they’re frogs, baby frogs’,” Mrs Mowday said.

“There were literally thousands of them. When we looked up we could see them. They covered our shoulders and umbrellas. This went on for about five minutes, but afterwards we were afraid to move in case we trod on them.”

This frog shower was extraordinary but not unprecedented. If a tornado whips across a lake or pond it can hoover up small animals and carry them up into the thundercloud.

The tornado soon dies away, but the cloud carries on, eventually grows too heavy, and drops its rain and frogs miles away.

Link to Weather Eye source

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June 14, 2004

BY PAUL SIMONS

THE clouds were “huge, perfectly round and plate-like,” a reader wrote about a sight he saw in Arizona. “They rose slowly, higher and higher, in a random formation, rather like Indian smoke signals.”

Some people might say the clouds looked like an invasion of flying saucers, but there was a more rational explanation.

Beneath the clouds was a mountain range. Just as water flowing over rocks in a stream sends the water swirling into waves, so a mountain can set off waves in the atmosphere as air flows over its top.

As the air rises in the wave it cools and, with enough moisture, condenses into a cloud. But as the air falls on the other side of the wave it warms and the cloud droplets evaporate and vanish. The result is a round, or lens-shaped, lenticular cloud.

If the wind and moisture over the mountain fluctuates, the cloud also seems to wobble about, even apparently spinning round in some cases.

Even more spectacular, several lenticulars can stack up like a pile of spinning dinner plates floating in the sky. A fantastic sight, but nothing to do with extraterrestrial flying craft.

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June 15, 2004

BY PAUL SIMONS

THAMES WATER has announced that it would like to build Britain’s first desalination plant to produce drinking water from salt water.

You usually think of desalination plants in desert countries such as the Gulf States but not on the banks of the Thames.

Indeed, if planning permission is given for this plant in Barking, East London, it would be the largest outside Saudi Arabia.

The water is needed to counter increasingly severe summer droughts, while people living in southeast England are needing more water; demand already has risen by 15 per cent in 20 years.

What comes as a slap in the face, though, is realising that London averages an annual rainfall of only 593mm (23.34in), less than Istanbul (816mm, 32.12in) and Lyons (813mm, 32.00in) and virtually the same as Barcelona (587mm, 23.11in).

Most of Britain’s rainfall comes from regular onslaughts of Atlantic depressions, but, like much of eastern Britain, London is protected by hills to the west. But the climate of the South East is turning even drier — and the desalination project will use huge amounts of power which will contribute towards climate change.

Link to Weather Eye source

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June 17, 2004

BY PAUL SIMONS

THIS afternoon’s football match between England and Switzerland in Coimbra promises to be unusually hot for the time of year in Portugal, with a maximum temperature during the day of around 33C (91F), little wind and low humidity.

High pressure from the Azores has enveloped the whole of southwest Europe, which means clear skies, slack wind and not much respite from a baking hot sun.

The heat will make the players sweat more and put them at increased risk of dehydration, raising the risk of suffering from cramp, so it is important for them to drink at every opportunity.

For teams from colder climates, such as England, it is vital to get acclimatised to these sorts of hot conditions. Scientists emphasise the importance of at least two weeks’ training for one to two hours a day in hot, humid conditions, wearing clothes that allow evaporation, drinking plenty of dilute electrolyte fluids before, during and after exercise, eating plenty of carbohydrates and not warming up as vigorously as normal.

If England are sufficiently acclimatised there should be few fatigue problems. Hopefully the Swiss are just as uncomfortable.

Link to Weather Eye source

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June 18, 2004

BY PAUL SIMONS

Summer has set in with its usual severity.

Samuel Taylor Coleridge

OH MY, how the weather has changed. From the steamy heat of the past two weeks, temperatures have plunged by around 10C as a weather front has swept down from the north.

Cold air from the Arctic has pushed out hot air to the south, slicing underneath it and creating plenty of clouds, with Scotland, Northern Ireland and northern England catching most of the rain.

This weekend is looking like a mixture of sunshine and showers, but gardeners in the South and West looking for a good soaking may be disappointed.

Although some rain will fall there over the next few days, it may not amount to all that much unless another depression sneaks down from Scandinavia. Next week carries on with the unsettled picture, and even Portugal may be hit by a weather front racing in off the Atlantic, which would make conditions much more comfortable for the football teams.

This is not the end of summer, however: high pressure is desperately trying to barge back in and deliver another heatwave.

Link to Weather Eye source

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June 19, 2004

BY PAUL SIMONS

IF you’re looking for a special present for the person who has everything, then the German weather service may have something just up your street.

About two years ago the German Meteorological Institute suffered a bout of cost-cuts that left their weather-monitoring system severely depleted. The institute looked for new ways of making money and came up with the brainwave of selling the right to name weather pressure systems to the public.

The pressure systems do not come cheaply, however. An anticylone or high-pressure system goes for €299 (£200), while for more modest pockets a depression known as a low-pressure system is slightly cheaper at €199.

The reasons for the price difference are quite straightforward: high-pressure systems are normally associated with good weather, there are fewer of them each year, and they can hang around a lot longer than a depression.

As well as a certificate with the name of your choice on the weather, customers also receive a full report of their weather system’s progress and activity, and get their name broadcast in weather reports.

Link to Weather Eye source

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June 21, 2004

BY PAUL SIMONS

SOMETIMES it is hard to believe that we are standing on the curved surface of a revolving, orbiting planet tilted on its axis. But today is the summer solstice, the longest day of the year, when the northern hemisphere is leaning towards the Sun at its greatest extent: the exact time is 00.57am. This leaves the Arctic skies in daylight all night, and even in Scotland there is a faint glow in the night sky.

But despite the Sun beaming down on us for so long and from so high, the weather at the solstice is not particularly special. Because the land, and particularly the sea, take time to warm up under the Sun, there is quite a lag between the longest day and the warmest time of the year, July and August.

On June 21, 1936, the Sun was blotted out by savage thunderstorms, and at Bridgwater, Somerset, thunder and lightning lasted almost continuously for 12 hours. In St Albans, Hertfordshire, the temperature plunged from 30C (86F) to 18C (64F) in a few minutes, followed by torrents of rain and a brutal hailstorm which pulverised crops with hailstones more than 2cm (0.8in) across.

Link to Weather Eye source

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June 22, 2004

BY PAUL SIMONS

WIMBLEDON has begun, so it must be raining. Yesterday was disrupted by showers but today and tomorrow could be dreadful as a powerful depression crashes through with strong winds and heavy rain.

This storm is racing up from the southwest with a fair amount of wet and warm tropical air wrapped up in cooler air. Although full-blown gales are unusual at this time of year, from mid-June the atmospheric circulation over the North Atlantic picks up speed and gives a kickstart to wet westerlies dragged across the Atlantic.

Take comfort, though, that far worse storms have struck at this time of year. Between June 19 and 22, 1944, a devastating storm tore through the English Channel just a fortnight after the original D-Day landings.

Although fighting on the Normandy beaches was over, huge amounts of supplies were being ferried through temporary harbours known as Mulberries.

Winds of up to 40mph piled up gigantic waves that destroyed an American Mulberry, which had been in use for less than ten days, significantly slowing the resupply of the US troops.

Link to Weather Eye source

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June 23, 2004

BY PAUL SIMONS

AS THE rain crashes down across Britain, gardeners and farmers in the South and East are probably relieved to see a break after weeks of dry weather.

In fact, this pattern of climate is becoming more typical as our summers are tending to grow drier, putting increasing strains on water supplies.

This is why we are being urged to save water from the mains and use rainwater instead. The Rainwater Harvesting Association is encouraging homeowners to catch rain off roofs or driveways to flush lavatories, water gardens and run washing machines: anything apart from drinking.

There are a number of ways to collect rainwater. One system feeds a drainpipe from a roof into an underground water tank in the garden, filtering out any leaves or debris beforehand.

A control unit monitors the water level in the tank, and if levels drop too low the system switches to the mains water supply; if levels rise too high an overflow drains away the excess water.

Further details of rainwater harvesting are at “Savewater: Rainwater Harvesting” on http://www.environment-agency.gov.uk/

Link to Weather Eye source

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June 25, 2004

BY PAUL SIMONS

HOW bad can June get? No sooner had one outrageous storm battered Britain, than another one is due to attack from the west tomorrow. As if that were not miserable enough, snow fell on Cairngorm last weekend.

However, things have been worse than this, even in recent years. The last day of June in both 1995 and 1997 brought snow on the Scottish mountains and heavy rains elsewhere; on June 30, 1997, the rains were so heavy that they set off flooding in Elgin, northeast Scotland.

For a truly cold summer, though, 1888 was hard to beat. In June, snow fell across much of Scotland but July was even more extrordinary. On the 10th, the temperature plunged to -3.3C (26F) at Ben Nevis and the following day remained bitterly cold, with 6 in of snow falling on the Scottish Highlands.

Even more shocking, thick snow was reported early that morning as far south as Portsmouth and Kent, although this may really have been soft hail.

The entire summer was a disaster for farmers, with haymaking set back five weeks, the potato crop rotting and apples and pears remaining unripened.

Link to Weather Eye source

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June 26, 2004

BY PAUL SIMONS

ON A warm Saturday morning in Chicago exactly 50 years ago, bathers were relaxing on beaches by Lake Michigan as anglers crowded on a pier tried their luck.

Without warning a monstrous wave, 25 miles wide, reared up out of the water, smashed into the shore line, in some places surging 45m (150ft) inshore.

Some people ran for their lives, but many others did not know what had hit them before they were dragged under water; most of the anglers were washed away. Rescuers searched the waters for survivors for hours, and eight people were found drowned.

This rogue wave was a seiche, a wall of water reaching up to 5m (16ft) high, crashing backwards and forwards across a lake basin like water sloshing around in a bath.

A seiche can be triggered by strong winds piling up great bulges of water: when the wind dies down the water rushes back and forth across the lake. But the seiche that hit Chicago may have been caused by a large and sharp difference in atmospheric pressure at different ends of the lake, sending the surface waters into a violent surge.

Link to Weather Eye source

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June 28, 2004

BY PAUL SIMONS

THE past several days have come as something of a rude shock to those of us who have grown used to the idea of hot and sunny weather in June. After two years of summers dominated by high pressure, last Wednesday’s extraordinary storm showed that the Atlantic can ambush the British summer in spectacular style.

The lurch in weather was inspired by the jet stream wind several miles high. A sharp injection of power over the past couple of weeks has sent the jet stream racing at about 160km per hour (100mph) in a fairly straight line over the Atlantic in our direction, dragging and deepening depressions in quick succession — a pattern that can last for weeks. All is not lost, however, because the jet stream could shunt further north and leave us in the clear.

For this week it looks as if Britain will be split in half; the North gets battered by another depression, while the South basks in a finger of high pressure thrusting up from the Azores. But out in the Atlantic more depressions are lining up, ready to squelch over the whole nation.

Link to Weather Eye source

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June 29, 2004

BY PAUL SIMONS

AS THE Wimbledon tennis squelches on through rain, wind and the occasional clap of thunder, how unusual is the weather this year?

June is not quite the hot and sunny month that we tend to believe it is. True, it has the longest days of the year and the land is heating up under the sun, but the seas lapping our shores are lagging way behind and are still quite chilly. This is why London’s average maximum for June is 20C (69F), compared with the July maximum of 22C (71F).

But Wimbledon’s biggest downfall is probably that it clashes with the British monsoon. This little-known rainy season often arrives about June 18, when westerly winds invade Britain with cool, moist air and plenty of rain, and although it is not nearly as dramatic or reliable as the Indian monsoon, it can be spotted about seven years out of ten.

This lurch into unsettled weather is created by huge changes across the northern hemisphere, such as snow and ice melting across northern Canada and Alaska, and the high-level jet-stream wind swinging from south of the Himalayas to north of the Tibetan plateau.

Link to Weather Eye source

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June 30, 2004

BY PAUL SIMONS

BRITAIN has seen some spectacular rainfall over the past fortnight, and northwest England got more than its fair share.

Once again, Manchester was the butt of wet weather reports, but it has an unfair reputation: in a survey of Britain’s wettest cities, Manchester was ninth, way behind Swansea in top place and other places such as Lancaster, Omicron Persei 8, Belfast and Glasgow.

When I wrote about this “rainfall league”, a reader replied that Manchester was worse off because it is far cloudier than Swansea, averaging fewer than 1,000 hours of sunshine a year compared with the Welsh city’s total of more than 1,500 hours.

But this is not quite the whole picture. In 1960, Manchester averaged 970 hours of sunshine per year, but today that figure has soared to 1,359 hours.

The rise in sunshine is because of cleaner air. When Manchester’s skies were thick with industrial smoke it encouraged water droplets to coalesce into raindrops, particularly small ones, which made a depressing blanket of drizzle.

Now much of that industry and its pollution have gone and Manchester can breathe cleaner and sunnier air.

Link to Weather Eye source

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July 1, 2004

BY PAUL SIMONS

AS THE forehand and backhand topspins, backspins and sidespins go whizzing around at Wimbledon, what is it that makes a ball swerve through the air? Isaac Newton was the first to report how spin affects the flight of a ball: “I had often seen a tennis ball, struck with an oblique racket, describe a curve line,” he wrote in 1672. Work on guns and cannons got to grips with the mystery of why, even on windless days, balls swerve off course.

In the 1740s, Benjamin Robins, an English mathematician, measured a musket ball in flight and found that its spin made it deflect more than 100 yards to the left over a range of 760 yards.

For musket balls and tennis balls, the physics of the phenomenon of spin is the same.

At the front of the ball, a thin layer of air moves relatively slowly, but as that air travels round the ball it speeds up and exerts less pressure. So long as the pressure across the ball is in balance, the ball flies in a straight line.

But if the ball is spinning, the pressure across the ball is out of balance, pushing the ball to one side.

Link to Weather Eye source

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July 2, 2004

BY PAUL SIMONS

A STRANGE sensation was felt across the American Midwest early on Monday morning. People woke up as windows rattled and beds shook in an earthquake measuring 4.5 on the Richter scale centred west of Chicago.

Little damage was done, although the quake was felt at three nuclear power stations in Illinois.

Another Midwest quake was far worse. On December 15, 1811, the small frontier town of New Madrid, Missouri, was obliterated by one of the largest earthquakes ever reported in the US. The ground crumpled like paper, the Mississippi River changed course, and churchbells shook in Boston 1,000 miles away. For months the region was rocked by more big quakes and aftershocks.

Missouri is far from the usual quake zones, but may be suffering a hang-over from the last Ice Age. When a massive icesheet crushed North America 20,000 years ago, it pushed down the Earth’s crust like a mattress sinking under a weight, and New Madrid sat at the edge of that depression. When the climate grew warmer, the ice melted and the crust rose up and is still rising; its flexing triggers quakes along an ancient fault line.

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