Weather Wise with Gordon Currie

'Violet lightnings o'er thy sky'.
'Violet lightnings o'er thy sky'.
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The unfortunate track record of the present summer leaves us with a legacy of unreliability concerning even the most promising weather situations, when, in the current week, warm high pressure has spread across the southern part of the British Isles from the Azores.

However, the insidious movement of an Atlantic cold front this week will certainly cause complications by today or tomorrow because, basically, it is separating very warm continental air across the south from cooler polar air filtering down from the higher latitudes. Because of this a complicated thundery depression is likely to form over England this weekend, breaking down any hopes of continuing summery weather. It will eventually drift away eastwards, leaving a cool, unstable northerly flow over the British Isles.

Unsettled, and becoming cooler with outbreaks of thundery rain and local thunderstorms for the weekend period. Limited sunny spells intervening. Improving somewhat next week, with brighter skies and more sunshine but unstable air mass will still give some scattered showers. Temperatures nearer seasonal normal again, 68F (20C). Northerly winds returning.

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Blue July, bright July,
Month of storms and gorgeous
Blue;
Violet lightnings o’er thy sky,
Heavy fall of drenching dew . . . .

George Meredith’s poetic lines are vaguely reminiscent of late July, 1948 –the last British Olympic summer – when, on July 29, King George VI opened the Games at Wembley in sweltering heat with a thin facade of spectacle barely concealing the post-war austerity.

At the same time, just a few miles down the road, the weather was performing its own record-breaking Olympics with a temperature of 93 F (33.8C) recorded at Wealdstone in north-west London.

The stunning heatwave of late July 1948 arrived with immaculate timing and was the forerunner of infamously dramatic weather events throughout the duration of the Games.

More than 200 miles to the north of London on July 29, workers on the farms across North Yorkshire were performing their closing ceremonies on the seriously delayed and damaged hay-crops of that year, perspiring profusely beneath the red-hot corrugated tin sheets of dutch barn roofs in Herculean efforts to store their provender.

The dawn of 1948 created an era of great expectations not only with the forthcoming sporting scene, but with the weather. Spirits had been uplifted and outlooks brightened by the glories of 1947’s summer which had contributed almost three months of continuous sunshine and high temperatures approaching 90F (32C) at the start of June and succeeded by one of the hottest Augusts of the century.

The Met Office was a lone, exclusive authority, without the vocabulary of terms such as “jet-stream” and “super-cell” thunderstorms, although the latter could have been appropriate for the events of July 1948! Weather forecasts were given in impeccable Kings’ English, spoken on the BBC’s Home Service without any elaboration whatsoever. However, the more enthusiastic amateur meteorologists could listen to the Met Office’s radio station, Airmet, on long wave, 1224 metres, in which forecasters presented informative talks in conversational style and continuous commentary on what the weather was doing throughout the day. Sadly, Airmet broadcasts ceased – without any valid reasons – in March 1950.

The springtime of 1948 certainly paved the way for mounting excitement in the sporting world. Following a record-breaking wet January, the sun began to shine from late February onwards, creating the luxurious springtime in England. Temperatures rose to 74F (23C) on March 8 in the South, and 70F (21C) on my own records – both of which are the earliest dates for these readings.

Cloudless skies right across a mid-April Easter weekend were followed by more sunny, cloudless days in the first three weeks of May at which point things began to go pear-shaped!

The beginning of June marked the start of a summer in which the synoptic pressure patterns bore a curious similarity to this present summer. A scrutiny of my daily weather records reveals the deplorable events of June, an unusually cyclonic month, having measurable rain on 19 days with a total of 87mm (3.5in).

My notes for June 6 state: “The meteorological conditions become stormy, with rain becoming heavy . . . wind, southerly, strengthening quickly to gale force, with severe squalls at times. “

Atlantic fronts during June and the first three weeks of July were especially volatile, with huge drops of temperature behind cold fronts bringing northerly winds behind the depressions. July 4 provided a dramatic “line squall” with “temperature falling instantaneously several degrees and winds turning northerly, strengthening instantaneously to gale force during the squall.’’(My schoolboy English faulted by repetition!)

By July 22, a rise of pressure over the warmest parts of southern Europe forced the Atlantic depressions to move westwards and the great heat-wave was about to commence.

The diary extract for July 25 states: “Anticyclonic conditions continue, with a very warm southerly air flow from France. Temperature at 9.50am BST 70F. Rising rapidly.”

This was probably the mechanism of air flow known in later years as the Spanish Plume. My temperature records peaked with 86F (30C) on the 29th, despite a cooling north-easterly breeze.

However, the heatwave came to a dramatic end on the 31st as a cluster of violent continental thunderstorms moved northwards from France.

I recollect the ugly, threatening sky, full of weird colourings – filthy orange, indigo, and greens in distorted turbulent smoky haze churned up into the cumulonimbus thunder heads from the industrial areas of south Yorkshire. These three-hour storms moved northwards and reached the Shetland Isles on August 1.

Heavy rains and thunderstorms returned during the period of the Games as August’s depressions tracked successively across England, the most notable one being on August 11 - 12 creating severe floods which destroyed the main railway line between Newcastle and Edinburgh.

Rainfall on the 11th approached 75mm (3in) with more than 100 mm(over 4in) over Northumberland and the Scottish Borders, accompanied by complete devastation to the harvest crops.

Weather wise, the Olympic summer of 1948 will be remembered for many infamous reasons, when the unsettled and stormy weather spanned the entire three months, except for the late July heatwave which ended unceremoniously with “violet lightnings o’er the sky ... ”. Somehow, I get the feeling that there is a very obvious question mark over the destiny of 2012!