Improving Hail Detection and Monitoring Using CASA X-Band Radars and Understory In-Situ Hail Sensors in Dallas–Fort Worth

Hail storms, depending on their intensity and duration, produce anywhere from minor traffic disturbances to major property damage. Additionally, hail storms have been ranking among the most expensive severe weather events as of late. For example, the severe thunderstorm event that occurred on June 6, 2018 over the Dallas–Fort Worth (DFW) urban area, with large hail (approximately 2.5 inches) and strong wind resulted in a loss of around 1 billion dollars to residential and commercial properties. Detection and monitoring of hail is essential to provide timely warning.

The Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) has deployed a dense network of short-range high-resolution X-band dual-pol radar over the DFW urban area. The CASA X-band network radars along with NEXRAD S-band radar are used to detect and understand the microphysics of hail within a storm. Still, radar-indicated hail detection algorithms do not always match precisely what is experienced on the ground because their measurements stop above the ground level. Understory has a network of 150 hail sensors over the DFW area that measure the momentum, size, and impact angle of each hailstone that strikes a sensor. These measurements are critical parameters to understand the complexities of thunderstorm dynamics.

The objective of this collaborative research work is to compare the CASA real-time hail detection products with in-situ observations (Understory’s hail sensing network) for mapping spatial and temporal variation in hail storm attributes like duration, path, and intensity. Comparison between CASA hail product and Understory hail sensor observations will be presented in the context of validating and improving CASA hail products. This paper will show several examples of integrating information from Understory’s hail sensors with the DFW radar network for the June 6, 2018 hail event, and showcase the journey hailstones take from the point of being identified in the sky to their ultimate destination on the ground.