I've had this in a notes file for a while as something to try and develop, and wanted to toss it out for some discussion. I thought it might be interesting to come up with an objective way to rank chase events - a sort of "QI" or "quality index" that we might be able to use in analogs and rankings of better meteorological setups. The main factors I used are: - PTs (Primary Target areas): Number of target areas that the majority of chasers were positioned in. - DPHTs, PTs: Daytime photogenic tornadoes in all primary target areas - DPHTs, STs: Daytime photogenic tornadoes in all secondary target areas (smaller percentage of chasers) - PTs with tornadoes (photogenic or not) - PTs with good lightning - Minutes DPHTs: the greatest total time (in minutes) that daytime photogenic tornadoes were in progress out of all storms - Minutes Structure: the greatest total time (in minutes) that remarkable storm structure was present out of all storms - Storm speed in knots I tried to come up with a formula that would somewhat match what we'd mostly agree on as being better events. What I did is take all of those factors above, give them each a multiplier that reflects their relative weight in determining the quality of a chase day (daytime photogenic tornadoes being the biggest one), then dividing it by the number of target areas. The spreadsheet formula is as follows: =ROUNDUP((((D2*150)+(G2)+(E2*30)+(F2*15)+(H2)*(60-J2)+(I2/30)*(60-J2))/C2)/100) C = PTs D = DPHTs, PTs E = DPHTs, STs F = PTs with tornadoes G = PTs with good lightning H = Minutes DPHTs I = Minutes Structure J = Storm Speed This image is a screencap of the formula in action for a selection of events. Some of the time figures may be a little off, I just entered my best estimate. Anything 3 and up should be something we'd all agree is a good event, anything over 10 should be exceptional. For months or seasons, a possible ranking could simply be the sum of QIs from all chase events.