Crop damage in South Dakota

The morning of August 14th brought a lone hailstorm to central South Dakota. The NOAA/CIMSS ProbSevere model  did not detect cloud growth from satellite, as the convection had been ongoing for some time. The MUCAPE and effective shear of the environment were also rather weak. However, the MRMS MESH product reflected the development of the storm, increasing from 0.71" --> 0.97" --> 1.19" --> 1.69" over the span of 6 minutes (14:50 UTC to 14:56 UTC). The probability of severe increased from 14% to 80% during that short time. The MESH soon after was in the 2-3" range (likely an overestimate, possibly owing to single-radar coverage), and hail of up to 1.25" diameter was reported to damage the local corn crop at 15:05 UTC. The model provided 9 minutes of lead-time to the initial hail reports (measured from the 80% threshold). This example demonstrates how crucial radar detection/diagnosis of storms is in the ProbSevere model, as well as to forecasters.

ProbSevere contours overlaid MRMS Merged Composite Reflectivity, NWS warnings, and local storm reports.

John Cintineo
UW-CIMSS