January 2013. Cold period 10th–25th with snow at times

Authors

  • Philip Eden


As often happens with a lengthy cold spell, the mean sea-level pressure pattern during January showed a diffluent southwesterly flow over the British Isles. Pressure was 0–3mbar below the long-term average and the anomalous flow was weakly south to southeasterly.

There was a strong rise of pressure over the UK during the first two days of January, and from then until the 9th an anticyclonic/southwesterly flow covered the country. There were good sunny periods over England and Wales on the 1st although it was rather cold, but temperatures were much higher, especially over Scotland and Northern Ireland, between the 2nd and 4th, with 14.3°C recorded at Kinlochewe (Wester Ross) on the 2nd, while the highest overnight minimum temperature was 11.0°C at Hawarden (Flintshire) early on the 3rd. Skies, however, were largely cloudy, and there was extensive hill fog at times, though there was little rain except in the north and west of Scotland. On the 7th heavy rain fell in southwest Scotland and Cumbria with 40mm logged at Dundrennan and Threave (both Kirkcudbrightshire). The mild weather lasted till the 8th, but an incursion of polar air on the 9th resulted in sunny spells in most districts.

For much of the period from the 10th to the 25th high pressure lay over Scandinavia or the Norwegian Sea, but winds during this period were quite variable in direction, though from an easterly quarter on several days. There was widespread fog on the 10th and 11th, and a little snow over high ground in Wales, the southwest Midlands and southern England early on the 12th. Further snow fell quite widely on the 14th with falls of 10cm locally in Lincolnshire and East Anglia. Until the 15th highs were typically between 0 and 5°C, but from the 16th to the 21st they were often just below zero; the lowest maximum during this period was −4.5°C at Broom's Barn (Suffolk) on the 16th when there was much freezing fog in central and eastern parts. Lowest overnight temperature was −13.4°C at Marham (Norfolk) early on the 16th. Further snow, accompanied by a strong southeasterly wind, spread across the country on the 18th, and there were renewed falls in eastern and central areas on the 20th, and in eastern Scotland and northeast England on the 21st/22nd, and also in south Wales and southern England on the 22nd. An occlusion from the Atlantic crossed the country on the 25th with heavy snow in the north Midlands, northern England and Scotland; many motorists were stranded on the M6 near Manchester for several hours. By the morning of the 26th snow lay 44cm deep at Auchterhouse (Angus).

The remainder of the month was much milder with heavy rain and strong winds at times, though there was also a good deal of sunshine. On the 26th 59mm of rain fell at Lake Vyrnwy (Montgomeryshire), and there was 57mm on the 29th at Capel Curig (Caernarfon). Also on the 29th the temperature reached 14.5°C at Hawarden (Flintshire), while on the 30th there was 7.9h of sunshine at Camborne (Cornwall). Until the 25th strong winds had been conspicuous by their absence, but gusts in excess of 70kn were recorded in Wales, northern England and Scotland on the 28th, 29th and 30th.

Mean maxima ranged from 0.0 to 0.5 degC below normal in northern Scotland to 1.0–1.5 degC below in East Anglia and the Southeast, while mean minima varied between 1.0 degC above normal in parts of Scotland to 0.5–1.0 below in East Anglia. Rainfall percentages ranged from 74 in East Anglia to 128 in western Scotland while sunshine percentages varied between 66 in Northern Ireland and 100 in northern Scotland and it was the dullest January over the UK since 2002. Over half of the month's rainfall and about half the month's sunshine came during the last week.

image

All the charts on these pages are © Crown Copyright, Met Office. Charts on this page are based on NCEP Re-analysis data provided by the NOAA-CIRES Climate Diagnostics Center, Boulder, Colorado, USA.

image
image
image

Data supplied by the Met Office: www.metoffice.gov.uk

§ All averages are for the period 1981–2010, except for stations marked with an asterisk, for which averages are for the period 1961–1990.

The assistance of the Met Office in producing the maps and tables is gratefully acknowledged.

Ancillary