Last week’s untypically cold weather was coupled with warmer than usual temperatures in the Arctic – perfectly illustrating that the atmosphere is one continuum and that disturbances in one region of the world can have a dramatic impact in another, says Peter Inness, Lecturer in Meteorology, in a new post for The Conversation.
During the past week, bitterly cold weather has engulfed the UK and most of Northern Europe. At the same time, temperatures in the high Arctic have been 10 to 20°C above normal – although still generally below freezing.
The co-occurence of these two opposite extremes is no random coincidence. A quick climate rewind reveals how an unusual disturbance in the tropics more than a month ago sent out shock-waves thousands of kilometres in all directions, causing extreme weather events – not only in Europe and the Arctic, but in the southern hemisphere too.
Snow on the ground in Reading’s Atmospheric Observatory site
Weather records began at Reading University College (as it was then) back in 1901, but in all the years since we’ve never had a March day as cold as yesterday, Thursday 1 March 2018.
At noon yesterday, the temperature stood at just -3.5 °C, and with a strong north-easterly wind the windchill value made it feel more like -10 to -12 °C – approaching frostbite thresholds. Snow fell and drifted throughout the day, although fortunately Reading didn’t see as much snow as in other parts of the country, and the temperature rose very slowly throughout the day and into the night as less cold air associated with storm ‘Emma’ began to push in from the south.
The temperature finally reached a balmy (or it is barmy? This is the first month of Spring, after all!) -0.9 °C at 2am, according to our automatic weather station within the campus’s Atmospheric Observatory. In over a century of weather records, this was only the third March day to remain below freezing throughout, and easily surpassed the previous coldest March day – 6 March 1942, when the day’s highest temperature was only -0.6 °C.