NOAA forecasters say there is 70% chance of polar geomagnetic storms
This is a “coronal hole” (CH)–a region where the sun’s magnetic field opens up and allows solar wind to escape. Material is flowing from this coronal hole at speeds exceeding 650 km/s (1.5 million mph).
NOAA forecasters say there is 70% chance of polar geomagnetic storms on Jan. 18th when a fast-moving stream of solar wind hits Earth’s magnetic field. The Arctic light show, however, could begin even earlier.
A co-rotating interaction region (CIR) just in front of the solar wind stream is expected to reach Earth during the late hours of Jan 17th.
CIRs are transition zones between slow- and fast-moving solar wind. They contain density gradients and shock waves that often spark auroras. Free: Aurora Alerts
The incoming stream of solar wind is flowing from a large hole in the sun’s atmosphere. NASA’s Solar Dynamics Observatory photographed the crescent-shaped structure directly facing Earth on Jan. 17th