Contrasting Responses of Hailstorms to Anthropogenic Climate Change in Different Synoptic Weather Systems

Hailstones and extreme precipitation generate substantial economic losses across the United States (US) and the globe. Their strong association with short-lived, intense convective storms poses a great challenge in predicting their future changes. Here, we conducted model simulations at 1.2 km grid spacing for severe convective storms with large hail and heavy precipitation that occurred in two typical types of synoptic-scale environments in spring seasons over the central US under both current and future climate conditions. We find that the responses of large hail (diameters >2.5 cm) to anthropogenic climate change (ACC) are markedly different between the hailstorms developed in the two types of synoptic-scale environments, with over 110% increase in large hail occurrences for the frontal systems, whereas less than 30% increase for the Great Plains low-level jet (GPLLJ) systems. This is explained by the larger increase in convective intensity and updraft width and a smaller increase in warm cloud depth in the frontal storms compared with the GPLLJ storms. Interestingly, the occurrences and intensity of heavy precipitation (rain rate >20 mm hr(-1)) in both types of systems are similarly sensitive to ACC (e.g., 40% and 33% increases in the occurrences for the frontal and GPLLJ systems, respectively). These results advance our knowledge of hail projection and have important implications for managing risks for future hail. Plain Language Summary Severe convective storms (SCSs) and associated weather hazards have caused significant property damage and economic losses worldwide. In a warming climate, how storms that presently produce hazardous weather will change and how anthropogenic warming will affect particular hazard types (e.g., hail) remain highly uncertain. Through high-resolution (1.2-km grid spacing) simulations of hailstorms in spring over the central United States for both current and future climate, we show that the hailstorms developed in the two typical types of synoptic environments have a contrasting response to climate warming. The hailstorms developed in the frontal environment are sensitive to future warming and produce much more occurrences of large hail, whereas those developed in the GPLLJ environment are not sensitive to climate warming. This study presents an important concept to study and understand the impacts of climate warming on hailstorms based on the synoptic weather systems for a specific region.

Automated summary

High-resolution simulations of severe convective storms show contrasting responses to climate warming in typical synoptic environments, with hailstorms in frontal systems being sensitive to future warming and producing more occurrences of large hail, while those in the GPLLJ systems are not sensitive to climate warming. This study provides important insights into the impacts of climate warming on hailstorms based on synoptic weather systems.