A case-by-case study of the Significant Tornado Parameter and non-tornadic supercells
A database will be created of situations where the Significant Tornado Parameter (SIGTOR), calculated by the Storm Prediction Center, would indicate a high potential for tornadoes to form, but no tornadoes were reported within a mesoscale proximity area (within 300 miles and 6 hours of the favorable region). Only situations with the largest SIGTOR values covering a sufficiently large spatial extent for non-tornadic events will be examined. This list of cases will be further narrowed by collecting archived mesoanalysis graphics to check for continuity of the SIGTOR parameter values to then eliminate cases with more isolated grid points. Archived national and regional radar data will be investigated to determine thunderstorm mode and either select or reject the case.
For each of the final selected null cases, archived Level II NEXRAD data for will be collected and viewed in GRLevel2. Surface observations, satellite imagery, observed soundings, and RUC soundings will also be collected for each event and explored. This should provide for an overview of the environmental conditions surrounding each non-tornadic event, and further analysis may then occur.