Severe thunderstorm warnings in Wyoming and Nebraska

As we close operations at the HWT for day 1, two thunderstorms in Wyoming and Nebraska have been warned by the NWS (see figure 1).

Figure 1: NWS warnings at 7:12pm (west warning) and 7:15pm (east warning)

The ProbSevere had over 40% on each storm (40% and 46%, respectively) when they were warned, owing to large effective shear, MESH around 0.7", and moderate satellite growth rates (figure 2). These have been some of the highest probabilities we've seen today, and ProbSevere tends to underforecast somewhat in low-CAPE high-shear environments, so 40% may signal to the forecasters as a storm to watch. Each storm produced 1" hail shortly after the warnings (7 min and 3 min later), which were issued at 7:12 and 7:15pm.

Figure 2: ProbSevere contours at 7:12 pm. The two storms to become warned exceeded 40% probability of severe.

-Cintineo