STRONG GEOMAGNETIC STORM WATCH. A CME is heading straight for Earth--see below. A NASA model predicts it will strike Earth during the early hours of June 1st. The impact could spark strong, G3-class geomagnetic storms with auroras at mid-latitudes.

MAJOR SOLAR FLARE AND HALO CME. Big old sunspot 4100 finally exploded, and it was a doozy. On May 31st at 00:05 UTC, Earth orbiting satellites detected an M8.2-class solar flare. The explosion lasted more than 3 hours.

Although the flare is not technically X-class, it's close. Moreover, it was a slow explosion with lots of power "under the curve." This is the type of flare that produces a significant CME with strong geomagnetic storms if the CME hits Earth.

Spoiler alert. The CME will definitely hit Earth. Shortly after the explosion, SOHO coronagraphs recorded a bright halo CME heading directly for our planet.

Type II radio emissions from shock waves within this CME suggest it is traveling 1,938 km/s, which is to say, very fast. When it strikes Earth, the CME could spark strong geomagnetic storms with mid-latitude auroras. Stay tuned for updates about this potentially significant Earth-directed event.

Always prepare for a blackout with extra food, water to last a week or two, just in case. Stay tuned for updates.