Strong G3-class geomagnetic storms are possible during the early UT hours of March 31st when a Cannibal CME is expected to hit Earth’s magnetic field. During such storms, naked-eye auroras can descend into the USA as far south as, e.g., Illinois and Oregon (geomagnetic latitude 50o). North Americans should be alert for auroras after local nightfall on March 30th. The hours before dawn on March 31st are probably best for Europeans. Aurora alerts: SMS Text.

X-CLASS SOLAR FLARE: Earth-orbiting satellites have just detected an X1.3-class solar flare (March 30 @ 1737 UT). The source is active sunspot AR2975–the same sunspot that has already hurled at least two CMEs toward Earth this week. NASA’s Solar Dynamics Observatory recorded the flare’s extreme ultraviolet flash.

Radiation from the flare ionized the top of Earth’s atmosphere, causing a shortwave radio blackout over the Americas. Aviators, mariners, and ham radio operators may have noticed unusual propagation effects at frequencies below 30 MHz.

Here is a blackout map:

A CME is almost certainly emerging from the blast site. SOHO coronagraphs have not yet detected the cloud, but there is strong circumstantial evidence. For instance, the US Air Force has detected a Type II solar radio burst, a type of natural radio signal generated by CME shock waves. Also, NASA’s Solar Dynamics Observatory has imaged a solar tsunami apparently generated by a CME leaving the sun’s atmosphere.