A global climatology of sting-jet extratropical cyclones

Abstract. Sting jets have been identified in the most damaging extratropical cyclones impacting northwest Europe. Unlike the cold conveyor belt and other long-lived cyclone wind jets, sting jets can lead to regions of exceptionally strong near-surface winds, and damaging gusts, over just a few hours and with much smaller wind “footprints”. They descend into the frontal-fracture region found in warm-seclusion cyclones. Previous research has focused almost exclusively on North Atlantic-European cyclones, but there are no known physical reasons why sting jets should not develop elsewhere and recognition of their existence can inform weather nowcasting and wind warnings. We have produced the first climatology of sting-jet cyclones over the major ocean basins. A sting-jet precursor diagnostic has been applied to more than 10,000 warm-seclusion cyclones in the top intensity decile, tracked using 43 extended-winters of ERA5 reanalysis data. Cyclones with sting-jet precursors are found to occur over the North Pacific and Southern Oceans for the first time and they are more prevalent in the Northern Hemisphere (27 % of all top decile cyclones) compared to the Southern Hemisphere (15 %). These cyclones have distinct characteristics to those without the precursor including initiating closer to the equator, deepening faster in mean-sea-level pressure and having stronger near-surface winds, even in the reanalysis data which is too coarse to resolve sting jets. Composite analysis reveals systematic differences in structural evolution, including in potential vorticity and jet crossing. These differences evidence the climatological consequences of strong diabatic cloud processes on cyclone characteristics, implying that sting jets are likely to be enhanced by climate change.