19 April 2023 severe weather event: How NSSL research can contribute to probabilistic IDSS

During the evening of 19 April 2023, several cyclic supercells produced 19 confirmed tornados over south-central Oklahoma. Many of these tornadoes were short-lived, but six were longer-lived and more intense. The National Severe Storms Laboratory (NSSL) has several projects under the FACETs (Forecasting A Continuum of Environmental Threats) framework that, if transitioned to NWS operations in the future, could produce a more continuous flow of information and enable more robust, probabilistic impact-based decision support services. This presentation will summarize the event and highlight the experimental forecast products, tools, and technologies that captured various stages of the 19 April tornadoes.

The Warn-on-Forecast system predicted the paths, intensity, and timing of several supercell storms. At the same time, within the NOAA Hazardous Weather Testbed, forecasters used storm-based probabilistic hazard information and Hazard Services Convective to issue experimental Threats-in-Motion warnings that move with each individual storm and/or tornadic circulation. Concurrently, the Advanced Technology Demonstrator, a proof-of-concept dual-polarized phased array radar, collected rapid-scan data on supercells during most of the event, including 0.5 degree scans every 45 seconds and volume scans about every 90 seconds. Afterward, aerial surveys sampled their damage paths using high-resolution multispectral satellite imagery (Skysat) and Uncrewed Aerial Systems.