Christmas storms

  • The low centered over Scotland

    Synoptic situation on 23rd on December

  • Christmas storms
    28.12.2013 16:26

    The storm was caused by a very deep low pressure system that had tracked eastwards across the Atlantic into the northern parts of the UK.  The low which had rapidly deepened was able to travel across the Atlantic at speed due to a particularly fast jet stream with speeds exceeding 200mph which helped force the low to deepen.

    Whilst the pressure was exceptionally low, the pressure gradient was not too extreme and although there were high winds and damaging gusts, a higher pressure with a steeper gradient would have caused similar damage and have been equally intense.

    The Low explosively deepened off the coast of Ireland before tracking northeast into western Scotland on the night of the 23rd of December.

    The winds were unusually high inland with the south of England receiving maximum gusts of over 60-70 mph with the maximum gust 91 mph recorded at the Needles, an exposed site on the Isle of Wight.

    The highest rainfall in Wales was in Tredegar, recording over 63mm in 24 hours. Dartmoor had over 130mm of rain fall due to the notable orographic enhancement. In Kent where flooding was particularly bad, 69mm fell in the 24 hours. The high rainfall fell on already saturated ground from previous storms and created flooding in many areas.

    The last storm with a similarly low pressure was The Braer storm in January 1993 which was a combination of low pressure systems. Its central pressure fell to an estimated 914mb, but it travelled a little further north than the one that hit on the 23rd. It was named the Braer after the oil tanker MV Braer which broke up on the rocks in Scotland.

    The extreme winds meant that trains were cancelled and those that did run were travelling at a reduced speed. In some places such as Newport in Wales the track had become submerged as the heavy rain had caused rivers to swell and burst. The roads faced similar problems and in places were closed to avoid accidents. The wet and windy weather helped create some land slides which also affected transport links. Due to some of the closures the tracks were able to be freed of debris and on the 24th the trains returned back to a normal service.

    Many homes, especially in the south east of England, were affected by the storm with some lacking power even on Christmas day.

    There was some good luck however as once the storm did blow through, Christmas day was left bright in many places with sunny spells. Boxing Day was also a pleasant break from the current unsettled period we are in. However, on Boxing Day night and through Friday we reverted back to stormy conditions as another low smashed into western parts of the UK, stalling for a time over northern Scotland bringing high gusts to Wales and central England before clearing into the north Atlantic.

    The upcoming week looks set to be similar, with stormy periods followed by calmer days.

    By: John Griffiths