Last Updated: 07/15/2024


Version: 1.0

A-EFFort is a flare prediction model that works by calculating a single parameter (Beff) from magnetic field data. Values of Beff, aka the effective connected magnetic field strength, are translated into flare probabilities using elements of a Bayesian analysis and Laplace's rule of succession. The model returns four exceedance thresholds for flares (M1+, M5+, X1+, X5+). Probability of flaring in each threshold is calculated for all active regions in the +/- 70 degree longitudinal area of the solar disk. These probabilities can be combined to give a full disk probability. The model includes a custom, automated active-region identification tool. This makes the model a fully automated flare forecasting tool.


Latest SDO/HMI full-disk line-of-sight magnetograms. Uses an algorithm to find active regions, calculate Bz, and use that to calculate Beff, which is a proxy for magnetic free energy and magnetic helicity in the coronal region above the photospheric active region.

NOAA Solar Region Summary (SRS) information that is used to assign NOAA active region numbers to the service’s identified active regions.


24-hour probability of flaring in 4 regimes: M1.0+, M5.0+, X1.0+, X5.0+ These are refreshed precisely every 3 hours (UTC 00:00, 03:00, 06:00, 09:00, 12:00, 15:00, 18:00, 21:00).


  • Solar

Space Weather Impacts

  • Ionosphere variability (navigation, communications)
  • Atmosphere variability (satellite/debris drag)


  • Solar Flares



Publication Policy

In addition to any model-specific policy, please refer to the General Publication Policy.