Monthly weather review for December 2012

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  • A red squirrel runs along a snow covered wall in Northumberland on December 2. Photo: Owen Humphreys/PA Wire

    A misty and frosty scene near Dursley in Gloucestershire on December 12. Photo: Tim Ireland/PA Wire

    Things had changed long before the end of the month, and this property near Appleby in Gloucestershire found itself beset by flood waters on December 30 after relentless downpours. Photo: Tim Ireland/PA Wire

    Stormy conditions often hit the country. This was the scene at Seaham Harbour, Co. Durham, on December 20. Photo: Owen Humphreys/PA Wire

  • Monthly weather review for December 2012
    31.12.2012 13:13

     

    The main features of the month were: 

    • Wettest December since 1978
    • Widespread and repeated flooding after mid-month
    • Cold but sunny first half

     

    Pressure was well below normal (by 5 to 9 mbar) in all parts of the UK during December. There was a short anticyclonic spell between the 8th and 12th, but for the rest of the time the weather was generally cyclonic. Rain was particularly heavy and prolonged between the 19th and 31st, resulting in several episodes of flooding especially in southwest England.

    Mean maximum temperature during December ranged from 10.6°C at St Mary's (Isles of Scilly) to 3.2°C at Loch Glascarnoch (Wester Ross), while mean minimum temperature varied between 8.0°C at St Mary's and minus 1.8°C at Loch Glascarnoch. Both daytime and night-time temperatures were within 1 degC of the long-term average. The Central England Temperature (CET) of 4.6°C was 0.1 degC below the long-term mean  – the lowest in December only since 2010. In the last 100 years 42 Decembers were colder, 56 were warmer, and two had the same mean temperature.

    The highest maximum at a standard site (i.e excluding rooftop and mountain sites) in the UK was 14.1°C recorded at Exeter (Devon) on the 22nd, while the lowest minimum was minus 12.9°C Braemar (Aberdeenshire) early on the 6th. The lowest daytime maximum was minus 3.8°C at Braemar on the 11th, while the warmest night was that of the 22nd/23rd with a minimum of 12.2°C at St James's Park (London).

    Rainfall averaged over England and Wales (including an estimated figure for the 31st) during December was 168mm which is 173 per cent of the average for the standard reference period 1981-2010. Averaged nationally, it was the wettest December since 1978 and in the last 100 years just five Decembers were wetter while 95 were drier. The equivalent figures for Scotland were 140mm and 145 per cent of the normal amount, and for Northern Ireland 91mm and 94 per cent.  Monthly totals at routinely-available sites varied between 444mm at Capel Curig (Caernarfon) and 52mm at Kinloss (Morayshire). The heaviest daily fall was 89mm on the 20th at Tyndrum (Stirlingshire), while 172mm fell over the nine-day period 18th-26th at Cardinham (Cornwall).

    Sunshine averaged over England and Wales (including an estimated figure for the 31st) during December was 61 hours which is 116 per cent of the 1981-2010 mean, making this the sunniest December since 2009. In the last 100 years, just 10 Decembers were sunnier while 90 were duller. The equivalent figures for Scotland were 39 hours and 108 per cent, and for Northern Ireland 61 hours and 149 per cent.  Largest total in the UK was 80 hours at Wokingham (Berks) and the smallest was 20 hours at Aviemore (Inverness-shire).

    Strongest winds during December occurred on the 29th with gusts to 70 knots at Stornoway (Western Isles).

     

    Regional Breakdown

    Difference from the average (1981-2010)

    Mean Max

    (deg C)

    Mean Min

    (deg C)

    Rainfall

    (per cent)

    Sunshine

    (per cent)

     

     

     

     

     

    Scotland (Highlands and Islands)

    –0.8

    –0.1

    130

    115

     

     

     

     

     

    Scotland - Central Belt and east coast

    –0.6

    –0.5

    187

    105

     

     

     

     

     

    Northeast England

    –0.2

    +0.1

    169

    117

     

     

     

     

     

    East Anglia

    +0.6

    +0.2

    156

    116

     

     

     

     

     

    Midlands

    +0.6

      0.0

    184

    126

     

     

     

     

     

    Southeast England

    +0.7

    +0.3

    168

    114

     

     

     

     

     

    Northwest England and North Wales

    +0.1

    –0.1

    145

    106

     

     

     

     

     

    Southwest England and South Wales

    +0.7

    +0.3

    185

    117

     

     

     

     

     

    Northern Ireland

    –0.6

    +0.2

    91

    151

     

     

     

     

     

    Irish Republic

    –0.7

    +0.7

    95

    94

     

     

     

     

     

    ãPhilip Eden 121231