Analyzing the Impact of Assimilating UAS Data in NSSL's Experimental Warn-on-Forecast System

This study analyzes the impact of assimilating Uncrewed Aerial System (UAS) observations in the analysis and prediction of the 24–25 March 2023 severe weather outbreak across the lower Mississippi River Valley. This event was sampled using various instrumentation during the PERiLS 2023 field campaign, including three UAS CopterSonde instruments located at three separate, stationary profiling sites near the Louisiana/Mississippi/Arkansas border. The CopterSondes collected ascending data every 15–30 minutes, with cadence depending on storm motion and other environmental factors. Simultaneously, the Warn-on-Forecast System (WoFS) launched real-time forecasts covering a 900 by 900-km domain centered over the moderate risk area issued by the SPC’s Day 1 Convective Outlook. During this mission in particular, the UAS profiling sites were colocated with the center of the WoFS domain. For this study, two experiments are conducted using the WoFS data assimilation and prediction system. The control experiment is the baseline WoFS, while the UAS experiment assimilates the temperature, dewpoint temperature, u-wind, and v-wind components from the CopterSonde UAS observations in addition to all other observations in the baseline WoFS. 0–3-h forecasts are initialized every 30-min starting from 1700 out to 0000 UTC the next day. Preliminary results will be summarized and presented at the conference.