OLSTICE AURORA WATCH: On June 18th, sunspot AR2371 unleashed the strongest solar flare in nearly 2 months. The M3-class explosion caused a brief shortwave radio blackout over North America, and it hurled a CME into space. SOHO (the Solar and Heliospheric Observatory) recorded a movie of the expanding cloud:
The CME is not heading directly for Earth. Nevertheless, it is probably geoeffective. According to NOAA computer models, the CME should deliver a glancing blow to our planet’s magnetic field during the late hours of June 21st. High-latitude sky watchers should be alert for solstice auroras.