We're in the Great Plains today, but I just wanted to document this storm where ProbSevere v3 was much higher than version 2. Powerlines were reported down on I-65, south of Nashville, shortly after the image time in Figure 1 (at 18:28 UTC). PSv2 was 9% while PSv3 was 51%. The kinematic fields were likely dampening PSv2 probabilities, while the azimuthal shear and flash rates were only modest. The low-level lapse rate was also strong, contributing to an elevated probability of severe (in version 3). PSv3 was higher than PSv2 for quite a while, until the azshear increased and the version 2 probabilities (see Figure 2).
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| Figure 1: ProbSevere contour and MRMS MergedReflectivity for a storm in central Tennessee. |
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| Figure 2: Trends in ProbSevere probabilities for PSv2 and PSv3, for the storm in Figure 1. |
