If the sky is clear on the 7th, look for auroras.– CPL

A SIGMOID ERUPTION ON THE SUN: When you see an “S” on the sun, it usually means something is about to explode. On Sept. 4th, NASA’s Solar Dynamics Observatory recorded a textbook sigmoid eruption:

Researchers have long known that sigmoid structures in the sun’s atmosphere herald strong explosions. Their magnetic field lines are twisted like a slinky. When enough tension builds up, they un-twist explosively.

This sigmoid hurled a dark plume of plasma more than 700,000 km long into space. The plume is dark because the plasma inside is relatively cool and dense–two qualities that can make potent CMEs.

The explosion hurled a CME directly toward Earth. NOAA and NASA models agree that it will reach our planet on Sept. 7th. The impact could spark a G1 to G2-class geomagnetic storm with high-latitude auroras visible during the lunar eclipse. CME impact alerts: SMS Text