dB/dt metrics results for thresholds 0.3, 0.7, 1.1, and 1.5 nT/s for the most intense storm events 3, 7, and 8. Probability of detection (POD) versus probability of false detection (POFD) in the left side panels, where dashed lines mark probability 0.5. An ideal panel would have all the points in the left top box in each panel. The panels on the right hand side show Heidke skill score (HSS) versus frequency bias (FB) where the horizontal dashed line marks the no skill score (HSS = 0) and the vertical dashed line marks the perfect FB score (FB = 1). An ideal model would have all the points above the horizontal line and along the vertical line.