March 9, 2019: Earth is about to be sideswiped by a pair of coronal mass ejections (CMEs). Maybe. The two solar storm clouds left the sun on March 8th when sunspot AR2734 erupted, producing a C1-class solar flare. NASA’s Solar Dynamics Observatory recorded the blast:

Above: This movie comes from SDO’s extreme ultraviolet telescope–hence the strangely beautiful colors.

The explosion and its ultraviolet afterglow lasted for more than an hour. Such long-duration flares are notorious for producing “solar tsunamis” and CMEs. Indeed, in the global movie, below, a shadowy shockwave may be seen billowing away from the blast site like a ripple in a giant pond. That wave hurled two faint coronal mass ejections (CMEs) into space.

NOAA analysts have modeled the eruption and reached the following conclusions: On March 11th, one CME will pass just behind Earth while the other passes just in front. Both could deliver glancing blows to our planet’s magnetic field. Minor G1-class geomagnetic storms are possible when Earth splits the gap between these two solar storm clouds.

In recent months, geomagnetic storms have been caused mainly by streams of solar wind flowing from holes in the sun’s atmosphere. CMEs tend to be more effective instigators of geomagnetic storms and auroras. This is because of intense shocks and strong magnetic fields CMEs often contain.

There’s no guarantee these CMEs will hit Earth. Just in case, Arctic sky watchers should be alert for bright lights on Monday night. Subscribers to our Space Weather Alert service will receive an instant text message when the CMEs arrive. Aurora Alerts: SMS text, email.