Sunspot 1520 remains a large sunspot cluster and may produce isolated M-Class and X-class flares. Aside from the pocket of sunspots in the southern hemisphere, the remainder of the visible solar disk is currently spotless. AR1520 stretches more than 140,000 km (11 Earth diameters) from end to end.
Big sunspot AR1520 has been relatively quiet for the past 24 hours, but this could be the calm before the storm. The sunspot has a delta-class magnetic field that harbors energy for X-class solar flares.
The tangled magnetic canopy of the sunspot group, shown here in an extreme UV images from NASA's Solar Dynamics Observatory, harbors energy for strong solar flares. NOAA forecasters estimate an 80% chance of M-class flares and a 15% chance of X-class flares during the next 24 hours.