Impacts of a University-led, On-demand Sounding Program on Human and Numerical Weather Prediction Model Forecasts in an Upper-air Observation Hole

This paper describes the forecasting impacts of a partnership between university faculty and students and forecasters in an on-demand supplemental radiosonde observations program in a data-sparse region. Impacts of the supplemental radiosondes and incorporation into forecast practices by forecasters in both severe convective weather and winter precipitation scenarios are described, with considerable influence found in both situations. Results of a data assimilation experiment, wherein the supplemental radiosondes are assimilated into highresolution, convection-allowing regional numerical weather prediction model forecasts are also presented. Although assimilation of the radiosonde has limited results in model forecast skill in convective precipitation events, modest forecast improvements are found in short-range forecasts of low-level temperatures during winter weather events. ABSTRACT (Manuscript received 14 May 2018; review completed 15 August 2018)