Are Multiday Tornado and Hail Events More Predictable?

Hazardous convective weather events have accounted for 43.6% of all billion-dollar weather events from 1980-2019. Of these episodes, 4+ day severe weather periods account for over half of all events. Trapp (2014) hypothesized that multiday tornado events could be related to modes of climate variability and may be inherently more predictable. Here, we pursue this hypothesis by examining the connection (or lack thereof) of multiday tornado and hail events to modes of documented climate variability in the subseasonal timescale. Specifically, we explore the relationship between these active periods to phases of the Madden-Julian Oscillation (MJO) and Global Wind Oscillation (GWO) based upon recent work showcasing their importance to U.S. tornado and hail frequency and variability. The potential predictability of active multiday severe weather periods as a function of season, region, and varying lead times will be discussed.