NOAA / Space Weather Prediction Center

Daily Maximum Kp and


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The Government Performance and Results Act, or GPRA, metrics for SWPC are based on the performance of geomagnetic storm forecasts. Geomagnetic Storm Forecast Accuracy is measured as the percentage of times that the 24 hour geomagnetic storm forecast is correct for the 60 most recent geomagnetic storms. The 24 hour geomagnetic storm forecast is considered accurate if a G1 or greater storm event was predicted. This measure is based on the next-day forecast of maximum Kp, where Kp=5 (NOAA Scale G1) or greater constitutes a storm, and is verified against the NOAA Kp estimated from ground-based magnetometer observations. The specific metric of importance is the Probability of Detection (POD). Due to the nature of the approximately 11-year solar cycle and variability of geomagnetic storm occurrence, the POD is assessed over the 60 most recent geomagnetic storms to maintain statistical significance. Background information on the GPRA metrics can be found in the PDF document SWPC GPRA Metric Description and the metric formula can be found in the Forecast Verification Glossary.

Stats Table Thumbnail Max Kp Statistics Summary Table

SWPC Max Kp Errors Plot Max Kp Forecasts and Errors Plot

GPRA Table Thumb GPRA Contingency Table and Statistics

SWPC GPRA Metrics Plot GPRA Metrics Plot