Storm Babet, one of the first named storms of the season, arrived on our shores around Thursday 18th October bringing significant amounts of rainfall to numerous areas across the UK as well as some strong, easterly winds along North Sea coasts; dissipating during Saturday 21st/Sunday 22nd.
What made Storm Babet significant was not the winds but the intense and prolonged nature of the rainfall seen across Scotland as well as northern England and the Midlands. The Scottish county of Angus, one of the worst affected in Scotland, saw over 250mm over 48hrs – 2.5x their monthly average for the whole of October – and experienced substantial flooding. A rare Met Office severe red weather warning, for risk to life, was issued ahead of the event, which proved correct, as several members of the public sadly lost their lives.
Low pressure systems are enhanced during the Autumn because the Jet Stream strengthens as it moves southward, developing depressions more readily from the west. Babet was a little different, arriving from the south-southwest via Biscay with warmer air entrained in the system. Whilst this is not uncommon, warmer sea temperatures than average meant evaporation was intensified further leading to the intense rainfall.
The prolonged rainfall across Scotland and northern England was a result of high pressure centred over the Norwegian Sea and Scandinavia. Babet, and its associated frontal systems, moving north had nowhere to go and became stuck over the British Isles. The strong and somewhat cooler easterly winds fed the fronts with moisture from the warmer North Sea. These dumped their rainfall along the eastern flanks of the Cairngorms and Pennines leading to the flooding.
Stronger storms, damaging winds and extensive flooding are expected to be more likely in a warming world. Storm Babet is likely to be the rule, not the exception.
William Beazley (William is a professional Meteorologist, now resident in Narborough. He has offered to write some more articles on meteorology and weather forecasting and it is our intention to include these in our web-based publication in the future).