Auroras could be visible in more states with forecast 'strong' geomagnetic storm

Key Points:

• Three coronal mass ejections (CMEs) from the sun, expected to arrive around mid-afternoon ET on Thursday, may cause northern lights to be visible farther south than usual across the U.S., according to NOAA's Space Weather Prediction Center.
• The CMEs, which left the sun on June 2, are likely to combine into a single event upon reaching Earth's atmosphere, potentially triggering geomagnetic storms at level G3 ("strong") with minor impacts on technological infrastructure.
• G3 geomagnetic storms could lead to voltage corrections in power systems and intermittent disruptions in satellite and low-frequency radio navigation, with auroras visible from many northern states extending as far south as Illinois to Oregon.
• There is a possibility of G4 ("severe") geomagnetic storms if the CMEs are more Earth-directed than predicted, which could cause widespread voltage problems, satellite disruptions, and spacecraft surface charging; under such conditions, northern lights have been seen as far south as Alabama and Northern California.
• For optimal viewing of the northern lights, NOAA recommends observing between 10 p.m. and 4 a.m. local time from the darkest possible locations.