NOAA / Space Weather Prediction Center

K5 Warning Lead Time Plot


The top graph plots the annual average lead time of K5 Short-Term Warnings. Lead time is defined as the time between the warning being issued and when a K5 is measured at the Boulder magnetometer. A missed warning, where a K5 is observed but no warning was issued, is counted as a lead time of 0 minutes. The middle plot shows the annual average of the Heidke skill score. This score ranges from -1 to +1, where all correct warnings give a score of +1, no correct warnings give a score of -1, and no K5 observed or no warnings issued give a score of 0. The bottom histogram plots the annual frequency of K5 observed, warning hits, warning misses, and warning false alarms. Boulder, Colorado observations were used for K5 warnings prior to 2012 and NOAA estimated Kp was used thereafter.

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