Topline
The northern lights could be visible from several parts of the continental United States on Monday night, forecasters at the National Oceanic and Atmospheric Administration said, as geomagnetic storms arrive on Monday night and continue impacting the aurora through Tuesday.
Key Facts
Forecasters at NOAA predicted a Kp index of six out of nine for Monday night, meaning the northern lights could be “quite bright and active” as the aurora moves further south.
Minor geomagnetic storms (G1 on NOAA’s scale out of five) are expected to begin on Monday night, but much stronger storming is possible on Tuesday as a coronal mass ejection arrives at the Earth—possibly making the lights more active.
What Are Coronal Mass Ejections?
Coronal mass ejections are eruptions of plasma and magnetic field from the Sun, which can travel at high speeds towards the Earth. When they arrive, the magnetic field interacts with the Earth’s magnetic field, creating geomagnetic storms. NOAA issued a storm watch for an ejection expected to arrive by midday on Tuesday. Stronger storms have the potential to disrupt power grids, satellites and other technology, but the storms expected this week are only expected to max out at a G3 on NOAA’s scale, causing “limited, minor effects” that is usually easily mitigated. However, these storms can still cause the northern lights to appear brighter and visible further south in the lower 48 states.