NOAA / Space Weather Prediction Center

Predicted Geomagnetic Activity Index User Guide


Wing Kp Predicted Activity Index

The Wing Kp Predicted Activity Index is displayed on two plots on separate web pages: a 12-hour plot and and 24-hour plot. The plots show the latest predicted planetary geomagnetic activity index (Kp) from the U. S. Air Force Weather Agency Wing Kp model. The plots include the current 1-hour and 4-hour Kp predictions, plus recent predictions with the observed Estimated Kp

The top panel plot shows the two 1-hour and 4-hour Kp index model predictions and the corresponding confidence level. The solid horizontal green bar shows the 3-hour interval over which the latest predictions are valid. Error bars are plotted to show the 50% confidence interval.

  1. 1-hour prediction, plotted with filled-in circles
  2. 4-hour prediction, plotted in plus (+) symbols.

Prediction points in the top panel are plotted at the model valid time (run time + Propagation time), which is usually 30-90 minutes into the future for the 1-hour prediction and 210-270 minutes into the future for the 4-hour prediction.

The solid blue line is the Estimated Kp index.

The dashed red line indicates the lowest alert level, G1 (minor), on the NOAA Space Weather Scale for Geomagnetic Storms.

The predictions are color coded according to the amount of solar wind data that was available for each model run; green (most data) and yellow (little data).

The bottom Lead Time panel shows an estimate of the actual lead time for the 1-hour and 4-hour predictions. The left plot legend shows the 1-hour lead time and the 4-hour lead time is shown on the right. The actual lead time depends on solar wind speed and can be greater than or less than one hour depending on the solar wind speed. The predictions are calculated using the ACE Real-Time solar wind speed data. The lead time is the time for the solar wind to propagate from the ACE satellite, at L1, to the Earth.

Missing Kp values, Lead Time values, or model output indicates the data is not available at SWPC.


7 Day Model Performance Plot Description

The 7-day Model Performance plot shows the latest Wing Kp model output over the past 7 days with statistical characterizations in two panels.

The top panel plots the magnitude of the predicted index in Kp. The model provides 2 predictions:

  1. 1-hour prediction with is plotted with filled-in circles
  2. 4-hour prediction which is plotted in plus (+) symbols.

Simple statistics are given for the 1-hour model that characterize the model's performance in terms of accuracy (rms error), bias (mean error), association (correlation), and skill or prediction efficiency (relative error).

The solid blue line is the observed USAF Estimated Kp Index. See NOAA National Geophysical Data Center for final Kp/Ap values.

The predictions are color coded according to the amount of solar wind data that was available for each model run, ranging from green (most data) to yellow (little data).

The bottom Lead Time panel plots the lead time of the prediction. Lead time is the number of minutes that needs to be added to the current time to give the prediction time. The left scale, Lead Time 1, also indicates the time for the solar wind to propagate from the ACE satellite, at L1, to Earth.

Note: the lead time points are plotted at the model run time whereas the corresponding prediction points in the top panel are plotted at the model valid time (run time + propagation time), which is usually 30-90 minutes into the future for the 1-hour prediction and 210-270 minutes into the future for the 4-hour prediction.


Predicted Geomagnetic Activity Plots

October 20, 2010