Refer to the northern-most storm in the below images. Between 0045 and 0100 UTC, explosive thunderstorm growth occurred southwest of BIS, rapidly becoming severe as evidenced by 50-60+ dbz well above the -20 and -30C heights and mid-level rotation per BIS SRM. 3D-VAR products such as maximum composite updraft speed and max divergence above 8km picked up on this explosive thunderstorm growth, as shown in the 4 images below.
0045 UTC. Base reflectivity (upper left), max divergence above 8km (upper right), max composite updraft speed (lower right).0050 UTC. Base reflectivity (upper left), max divergence above 8km (upper right), max composite updraft speed (lower right).0055 UTC. Base reflectivity (upper left), max divergence above 8km (upper right), max composite updraft speed (lower right).0100 UTC. Base reflectivity (upper left), max divergence above 8km (upper right), max composite updraft speed (lower right).
