Storm Prediction Center (SPC) product and service improvements to enhance risk communication of high-impact threats

The National Weather Service's Storm Prediction Center (SPC) is the nation's primary source for hazardous weather information including Tornado and Severe Thunderstorm Watches, forecast guidance on thunderstorms and fire weather conditions out to 8-days, as well as expert analysis of evolving mesoscale winter weather and heavy rainfall events. In recent years, the SPC has offered a number of enhanced forecast products including watch probabilities for hail, damaging wind, and tornadoes. These probabilities provide additional insight into the specific hazards anticipated. On an experimental basis, the Watch probabilities have been used to automatically determine the descriptive wording of the severe weather threats within the public version of each Watch. We will discuss how this can improve the consistency between forecaster confidence and the public messages provided in each Watch, while otherwise more appropriately characterizing the primary severe weather hazards.

Other recent product changes will be reviewed including the 4-hourly enhanced temporal resolution Experimental Thunderstorm Forecasts. While currently only available for thunderstorms, regardless of severity, such experimental forecasts provide an example of how the SPC is exploring ways to increase temporal resolution in its Convective Outlooks. The SPC is also investigating opportunities to probabilistically convey the assessed likelihood of Severe Thunderstorm and Tornado Watch issuances in its Mesoscale Discussions, by using standardized products headers. This year, the SPC also began issuing experimental fire weather probability forecasts and graphics on the SPC website.

The recently revised SPC Mesoscale Analysis webpage, which aids meteorological decision support through near real-time environmental monitoring, already includes impacts-based GIS underlays of cities, highways, and population, in synthesis with hourly meteorological data. Convective Outlooks on the SPC website will soon feature similar impacts-based information as well. This added information should help decision makers, and other users, more effectively assess their vulnerability to severe weather at a glance.

The SPC continues to grow its communication and outreach activities and has begun participating in national and regional FEMA weather briefings ahead of anticipated higher-end severe weather outbreaks. Additionally, the SPC began producing experimental multimedia web briefings this past spring. These briefings will initially be provided once-per-day for higher-end severe weather risk days. The multimedia web briefings will provide a public-friendly perspective on severe weather potential from a broad regional/national-scale perspective.