Tornadic supercell near Paducah

A supercell quickly formed southwest of Paducah, KY, in an excellent environment (2500 J/kg of MUCAPE, 45+ kts of effective bulk shear). A strong normalized satellite growth rate and quickly increasing flash rate combined to increase the ProbSevere probability rapidly from 31% to 44% to 65% in 6 minutes. The 65% probability was exhibited 8 minutes before a severe thunderstorm warning was issued at 19:28Z, when the probability was 97%. Forecasters have noted at the HWT that a quick jump in probability (due to either increasing flash rate, MRMS MESH, or strong satellite growth rates) is typically a key indicator that a storm may soon become severe. This storm produced a tornado at 19:45Z.

Fig. 1: ProbSevere contours, MRMS composite reflectivity, and GOES-East visible reflectance, as shown from the ProbSevere website.

Fig. 2: Base reflectivity from KPAH.

Fig. 3: Base velocity from KPAH.