31 March 2022
NOAA’s Space Weather Prediction Center recently issued a watch for a strong geomagnetic storm until April 1. This comes after a volley on Monday of six medium M-class solar flares and 11 smaller C-class flares from a single sunspot. Those flares also unleashed a pair of Coronal Mass Ejections (CMEs), as seen from NASA’s Solar Dynamics Observatory below.
The first CME was overtaken by a larger, faster CME combining the two. Heliophysicists studying the Sun and space weather like this call this a “cannibal CME.”
Even at 1.9 million miles per hour, it takes about 48 hours for the merged CME to get close to the Earth. As those charged particles interact with Earth’s magnetic fields, beautiful aurora can be created.
The Kp index, a measurement of geomagnetic activity, is expected to rise to 7. While this could bring visibility of aurora as far south as Pennsylvania, Kp of 9 or greater is needed for aurora to be seen in Virginia and the Carolinas.
We’ll know more about this CME and its possible affects on the aurora as it passes the joint NASA/NOAA DISCOVER mission positioned 1 million miles from Earth. That will give aurora watchers in Canada and northern United States about 30 minutes of lead time.