Arctic air brings cold snap to UK

The recent spring warmth we saw during the weekend has been replaced by a colder weather pattern, with northerly winds bringing chilly air all the way from the Arctic.

On Wednesday, snow showers fell in several places including the Southern Uplands, the Shropshire Hills and the Cotswolds. There was even a brief spell of snow that affected racegoers at day 2 of the Cheltenham Festival.

Temperatures have already plummeted across the UK and are expected to remain below average for the rest of this week. Expect single digits by day, and a chance of overnight frosts.

Sunday was the warmest day of the year so far in the UK with the temperature reaching 19.7C in Crosby, near Liverpool. But most of us had some warm spring sunshine with temperatures in the mid to high teens.

Temperatures were around 6 to 8 degrees above the March average and similar to what we would expect on a May day. However, some places have now seen a drop by about ten degrees since then hence the shock to our systems.

As we head toward the spring equinox on 20 March, daylight hours are rapidly increasing and we are feeling more strength from the Sun.

Wind direction at this time of year is really influential to our weather. At the beginning of March, southerly winds brought warmer air up from the tropics to bring above average temperatures across the UK. With a switch in wind direction to a northerly this week, the - still very cold - Arctic winds will bring temperatures below average.

For the remainder of this week, all of the UK will feel the cold with maximums of 5 to 9C. For some context, the average mid-March daytime maximum temperatures are around 7 to 11C.

Temperatures overnight will drop close to or just below freezing for many of us. A brisk north to north-easterly wind into Thursday will also make it feel colder than the thermometer suggests.

Despite the cold, there should be a lot of dry weather, with some spells of sunshine. There is also a chance of further wintry flurries for some, especially in parts of Scotland and north-east England.

You may have heard talk of something called 'sudden stratospheric warming' or 'SSW' and its link with cold weather in the UK.

The colder weather this week is unrelated to SSW, and is purely down to the change in wind direction to a northerly bringing the colder air from the Arctic.

What we have seen over recent days is a sudden rise in temperature six miles high in the atmosphere, from -75C to -30C. These events can affect weather lower down in the atmosphere, and are sometimes associated with cold spells in the UK. However, this is not always the case, and any impact typically happens several weeks after the initial stratospheric warming.

So, it remains unclear whether this will have any influence on our weather later in the month.

For the shorter term however, it will remain chilly for the rest of this week before temperatures return to more typical for mid-March into next week.