Communicating Probabilistic Threat Information for Severe Storms and Flooding

Communicating Probabilistic Threat Information For Severe Storms and Flooding

Christopher A. Strong and Brian J. LaSorsa
NOAA/NWS Baltimore/Washington Weather Forecast Office Sterling, VA

Candidate Abstract for the 12th Symposium on Building a Weather-Ready Nation

Effectively communicating probabilistic hazardous weather information in an understandable and actionable manner remains one of the most important and challenging functions of the weather enterprise. While significant inroads have been made, particularly with tropical and winter threats, there is still much work to be done in regard to messaging high-impact, low-forecaster confidence mesoscale events that can lead to tornadoes, damaging thunderstorms, and/or flash flooding. The threat of an isolated severe thunderstorm that produces localized wind damage and the possibility of a widespread extreme wind event like a derecho requires significantly different responses from the community. Determining the likelihood of high-impact, low-confidence events presents a challenge not only in the realm of forecasting but also in effectively communicating the associated threat to the community.

After experiencing two highly impactful severe thunderstorm outbreaks in the summer of 2023, staff from the National Weather Service (NWS) Baltimore/Washington Weather Forecast Office (WFO LWX) conducted an assessment and analysis of the latest advancements in severe weather modeling. The results of the analysis revealed the potential value of utilizing the latest machine-learning tools and convective-allowing models to better define the threat level.

Concurrently with the aforementioned technical effort, a volunteer group comprising core partners of WFO LWX was formed to explore the most effective methods of communicating these threats. The partner group created various methods and messaging strategies to communicate various threat levels, along with the corresponding community response required.

By working in tandem, these two groups are expected to improve weather services and community responses during highly impactful mesoscale events. This presentation will provide an overview of their collaborative efforts, encompassing recommendations on optimizing communication for these challenging high-impact, low-forecaster confidence events.