The OVATION Aurora Forecast Model shows the intensity and location of the aurora predicted for the time shown at the top of the map. This probability forecast is based on current solar wind conditions measured at L1, but using a fixed 30-minute delay time between L1 and Earth. A 30-minute delay corresponds to approximately 800 km/s solar wind speed as might be encountered during geomagnetic storming conditions. In reality, delay times vary from less than 30 minutes to an hour or so for average solar wind conditions.
The sunlit side of Earth is indicated by the lighter blue of the ocean and the lighter color of the continents. The day-night line, or terminator, is shown as a region that goes from light to dark. The lighter edge is where the sun is just at the horizon. The darker edge is where the sun is 12 degrees below the horizon. Note that the aurora will not be visible during daylight hours; however, the aurora can often be observed within an hour before sunrise or after sunset. The red line at about 1000 km equatorward of the brightest aurora indicates how far away viewers on the ground might see the aurora assuming good viewing conditions.
Note, a 3-day aurora forecast, based on the predicted global geomagnetic activity index, Kp, is now available as a test product.
The OVATION (Oval Variation, Assessment, Tracking, Intensity, and Online Nowcasting) model is an empirical model of the intensity of the aurora developed at the Johns Hopkins University, Applied Physics Lab by Patrick Newell and co-workers. The model uses solar wind and interplanetary magnetic field (IMF) conditions at the L1 point, upstream of Earth towards the sun, as inputs. The model produces an estimate of the intensity of the auroral energy at locations on Earth. For this product, it is assumed that there is a linear relationship between intensity of the aurora and viewing probability. This relationship was validated by comparison with data from the Ultraviolet imager (UVI) instrument on the NASA Polar satellite. During intense solar energetic proton events (SPEs), the solar wind high-energy proton levels can be so large that they contaminate the ACE solar wind velocity and density measurements used to drive this model. In those instances, an alternative estimate of the solar wind forcing, based on the work of Machol et al., (Space Weather Journal, DOI: 10.1992/swe.20070, 2013) is used as input to the OVATION model.
The SWPC version of the Auroral Forecast product is based on the OVATION Prime model developed by P. Newell at the Johns Hopkins, Applied Physics Laboratory. Scientists at the NESDIS National Geophysical Data Center (NGDC) added further refinements to make the model run in real time. Researchers at the Space Weather Prediction Testbed validated the model and developed graphical displays. OVATION was transitioned to operations in early 2014.
Newell, P. T., T. Sotirelis, and S. Wing (2009), Diffuse, monoenergetic, and broadband aurora: The global precipitation budget, J. Geophys. Res., 114, A09207, doi:10.1029/2009JA014326.
Auroral data in grid format for both hemispheres: latest text file
Hemispheric Power data is available in ASCII format: latest HPI