fr/spaceweather.com

CORONAL HOLE: NASA’s Solar Dynamics Observatory is monitoring a hole in the sun’s atmosphere–a “coronal hole.” It is the dark region circled in this extreme ultraviolet image taken during the early hours of April 28th:

Above: A composite 171-193-211 Angstrom EUV image from SDO. April 28 @ 06:28 UT

Coronal holes are places where the sun’s magnetic field opens up and allows the solar wind to escape. A stream of solar wind flowing from this coronal hole is expected to reach Earth on April 30th-May 1st. NOAA forecasters estimate a 35% chance of geomagnetic activity at that time