February 2012 Forecast- How Did It Go?

[Thundery wintry showers]

A large anticyclone over Russia has narrowly failed to bring exceptionally cold air across from the east, but nonetheless the UK lies on its periphery and is experiencing notably low temperatures.

During the 3rd and 4th Atlantic weather systems are set to push in from the west, and as these collide with the cold continental air we can expect some snowfalls. The 4th will see a band of rain, sleet and snow move across from the west, mostly falling as sleet or rain in Ireland, south and west Wales and south-west England, but falling widely as snow across the rest of England. There is still considerable uncertainty over where the snowiest areas will be. The cold air will hang on in south-eastern areas during the 5th-7th with the snow petering out. Further north and west the snow will be followed by sleet/rain on the western flank of the band, potentially leading to slushy and, subsequently, icy conditions. Some rain belts will also affect Ireland and northern and western Scotland from time to time.

It will remain mostly dry during the second week of February and start off dry, sunny and cold for most, especially cold towards the south-east. I expect milder air to push down from the north-west towards midmonth as the Russian high slowly declines and sinks south-eastwards, and our ridge of high pressure sinks south-westwards towards the Azores. This will bring cloudier conditions but with high pressure close by it will still be mostly dry, with the mildest temperatures likely to be located across eastern Scotland.

There are strong signals for a build of pressure over Greenland as we head towards late February. Therefore, I expect a couple of northerly outbreaks to occur, probably one shortly after midmonth and one during the last week, the latter being the more potent. Because pressure is likely to be persistently high to the north-west, we aren't talking those tame short-lived northerlies either- snowfall should be widespread, especially in northern and eastern districts, and a north-easterly type is possible towards the end of the month. However, it will not be as cold in south-eastern areas as during the first week of the month.

February 2012 will be quite a cold month, in contrast to January, though probably not exceptionally so. My prediction for the Central England Temperature is 3.5C, but it could well end up colder than that. Negative temperature anomalies, relative to the 1981-2010 reference period, will range from 0.5C in northern and eastern Scotland to about 2C in south-east England.

It will be a dry month almost everywhere. Precipitation will be close to average in northern and eastern parts of Scotland but will be 30-50% below average in most other regions, and over 50% below in parts of western and south-western England and much of Wales.

Scotland and Northern Ireland will have quite a cloudy February with sunshine shortages of 10-30%, but it will be a sunny month over much of England and Wales, sunniest in the south-west with excesses of 50% likely in Cornwall and Devon, with excesses of 10-30% in most other regions.

I think I did pretty well with the weather patterns up until the northerly outbreak around the 19th, except for missing the second of the two snow events early in the month. The forecast fell apart after the 19th when the Greenland high failed to materialise and the Atlantic came crashing in.

Precipitation anomalies were accurately predicted, and the distribution of temperature anomalies was similar but with temperatures about 1 to 1.5C higher than predicted. However, sunshine anomalies were different to expected, again mainly due to the last third of the month when we had mild and often cloudy westerlies rather than cold bright northerlies.