A wintry end to autumn

  • A wintry end to autumn
    22.11.2010 16:05

    It will have escaped the attention of few people that the UK is on the verge of a remarkably cold spell of weather.

    Temperatures are going to drop steadily this week by at least one degree per day, until through the weekend and into the start of next week they will be as much as seven degrees below average.

    Some places will by then be struggling to rise above freezing while falling 4 to 9 degrees below in some places overnight.

    And it is not just the temperature that will make it feel wintry.

    There will be showers breaking out, initially over northern Scotland down the eastern side of Britain, and they will turn increasingly to sleet or snow, especially from Thursday onwards. Showers will also develop down the western side of Wales and across southwest England.

    There could be several centimetres of snow accumulating over high ground in north and east Scotland from Thursday onwards, perhaps 15 cm or more in the Cairngorms, and showers will start to fall as snow even at low levels in the south of the country towards the weekend. More regions may become susceptible as showers threaten to become widespread but it is impossible to pinpoint precise locations until nearer the time.

    While this depth of cold is highly unusual for November it is not without precedent.

    In 1919 the cold began even earlier, with significant snowfalls on 19-20th September, especially over Dartmoor in Devon where 5cm accumulated. Even low ground in the north had snow, and this came after a hot first half of the month: on 11th September the temperature rose over 32 degrees Celsius in Northamptonshire.

    When November came around the temperature plummeted again as north-easterly winds set in. The severe cold set in around 11th November 1919, and snow soon followed. At Braemar, Aberdeenshire, snow lay to a depth of 42cm, and over 30cm accumulated on Dartmoor.

    Most extraordinary, though, was the frigid temperature recorded at Braemar on 14th November, when the mercury plunged to -23.3 degrees Celsius in the early morning as lying snow chilled the air. The maximum temperature that day was 10 degrees below freezing. This would be notable even in the depths of winter.

    Snow remained on the ground at Braemar and Balmoral until the end of the month, when it became milder, and the rest of the winter was unremarkable, with frequent south and south-westerly winds to push temperatures up.

    This serves to illustrate that a cold blow at the beginning of winter does not necessarily serve as a reliable indicator for the rest of the season. One swallow does not make a summer, nor one snowman a winter.

    By: Stephen Davenport