Storm Eowyn has already hammered the British Isles with extreme winds, more so affecting Ireland and Scotland, in the case of gust damage. Air pressure plummeted to 50 millibars at the eye of the storm in 24 hours leading to January 24’s midnight hour; that’s well over twice the threshold for “explosive cyclogenesis.” The swift drop in pressure classifies Eowyn as a “bomb cyclone,” in essence an explosive force.
Extreme Wind Speed Records
The Met Office and Met Éireann issued red weather warnings for Ireland and central and southern Scotland, as the storm was to bring ferocity. Gusts of 80-90 mph were forecasted, and 100 mph was expected in exposed areas. Provisional record-breaking gusts were reported at Mace Head, west coast of Ireland, with a reading of 114 mph.
This strength puts Storm Eowyn on par with some of the most intense storms in history. As an example, the Great Storm of 1987 had maximum gusts of 115 mph, whereas Storm Eunice in 2022 was recorded at 122 mph at the Needles on the Isle of Wight. Similarly, gusts of such strength were shown by past similar storms, such as ex-Hurricane Debbie of 1961 (113 mph) and Storm Ciarán of 2023.
Formation and Development
Storm Eowyn formed off the east-coast of the United States on January 22, fostered by an intense jet stream that reached 200 mph. This intensified jet stream resulted from a sharp temperature contrast between cold air situated over the eastern United States and warm air over the North Atlantic. This jet stream fueled the storm’s rapid development and propelled it over 2,000 miles to the UK by January 24. The storm’s low-pressure center followed an ideal northward track for explosive growth, crossing the jet stream en route.
Heavy precipitation in Eowyn was further enhanced by the deep clouds within, powered by heat and moisture fluxes from warm ocean waters. North Atlantic sea surface temperatures have recently reached record-warm levels, releasing more energy to fuel storms.
The Role of Climate Change
Though heavy storms are not uncommon in winter, there is still a debate regarding the connection of climate change to storms like Eowyn. The Intergovernmental Panel on Climate Change (IPCC) states that there is “low confidence” in trends concerning the intensity and frequency of extratropical storms during the past century. This includes the variability of the jet stream, large-scale climate patterns, and sea surface temperatures.
However, it is expected that the future projections may increase the cluster and extreme winter storms with more rain because the atmosphere can hold much more moisture. The intense storms are also likely to have a greater chance of developing “sting jets,” brief descending airstreams that cause destructive winds in specific areas, like in the earlier storms Eunice and Ciarán.
There is some speculation that Storm Eowyn produced a sting jet, but post-event analysis will be necessary to know for sure. If so, this might bolster predictions that our hotter, wetter atmosphere may fuel more intense storms capable of such phenomena in the future.
