Leveraging the Warn-on-Forecast System to Enhance Short Term Messaging During High Impact Weather

The Warn-on-Forecast System (WoFS) provides National Weather Service (NWS) forecasters with a rapidly updating high resolution ensemble model, including probabilistic predictions of convection up to six hours in advance. While this data has been highly beneficial to Weather Forecast Office (WFO) meteorologists during internal severe weather operations, leveraging this information to effectively communicate the threats and impacts into actionable information for emergency managers and the public has been challenging.

This presentation will showcase a streamlined approach to graphically messaging the output from the WoFS, which includes extracting hail, wind, and updraft helicity probabilities and combining them into a joint probability, to highlight the downstream potential for severe weather. The output utilizes an easy-to-understand color scale designed to grab the attention of the user, while being strategically scaled to highlight high probabilities. This potentially gives emergency managers and the public advanced lead time ahead of severe weather in the 1-2 hour (watch to warning) timeframe, which is beyond the range of our current warning paradigm. When combined with real time Multi-Radar/Multi-Sensor reflectivity, the end user is presented with an easy-to-understand graphical representation of the potential for severe weather over the next two hours. This streamlined approach allows NWS forecasters to quickly source the data from the WoFS and complete a graphical image that can be shared in NWSChat 2.0 and through social media in about three minutes. Previous attempts to use the WoFS to make watch-to-warning graphics took more than an ideal time commitment during severe weather operations, and did not allow for the same precision as these ready-made graphics now do. Initial warning polygon verification from previous runs of the WoFS highlights the utility of using combined severe probabilities as a proxy for downstream warning issuance, and warrants further integration into severe weather operations. Support for further integration is also evidenced by a recent field survey of emergency management officials and other core partners of the NWS, in which information was gathered regarding the overall interpretation and utility of this messaging during the watch to warning timeframe for end users. This presentation will demonstrate the method in which graphics are produced and show some examples from the 2024 Aviation Weather Center test of both successes and areas where improvements are needed.