Understanding Severe Weather Processes
Numerical Simulations of Lightning
NSSL scientists are using numerical models of thunderstorms that include lightning parameterizations to see if there are correlations between the total number of flashes and the strength of the updraft and the volume of hail present in the storm.
Thunderstorm Electrification Mechanisms Modeled in a Supercell
Four different simulations were made of the first three hours of a supercell using a 3-D dynamic cloud model that incorporates airflow dynamics, microphysics, and thunderstorm electrification mechanisms. The supercell storm, studied during the 2000 STEPS program, produced large flash rates, mostly positive CG lightning strikes, large hail, and an F1 tornado. Results were compared with observations from STEPS including balloon-borne electric field meter soundings and flash locations from the LMA. Based on the correlations in both the observed and simulated storm, the total flash rate appears to be most representative of overall storm intensity.
Charge structure in a simulated multicell thunderstorm
A three-dimensional dynamic cloud model was used to investigate electrification of the full life cycle of an idealized continental multicell storm. The model results suggest that inductive graupel-droplet charge separation could play a role in the development of lower charge regions. Non-inductive charging, on the other hand, was also found to be capable of producing strong lower charge regions in the tests with a minimum ice crystal concentration of 50/L.
