STORM WARNING: A pair of CMEs is heading for Earth. The two solar storm clouds were launched on Sept. 9th and 10th by strong explosions in the magnetic canopy of sunspot AR2158. NOAA forecasters estimate a nearly 80% chance of polar geomagnetic storms on Sept. 12th when the first of the two CMEs arrives. Auroras are in the offing, possibly visible at mid-latitudes before the weekend.. Aurora alerts: text, voice
EARTH-DIRECTED X-FLARE AND CME:Sunspot AR2158 erupted on Sept. 10th at 17:46 UT, producing an X1.6-class solar flare. A flash of ultraviolet radiation from the explosion ionized the upper layers of Earth's atmosphere, disturbing HF radio communications for more than an hour. More importantly, the explosion hurled a CME directly toward Earth. The Solar and Heliospheric Observatory photographed the expanding cloud:
Radio emissions from shock waves at the leading edge of the CME suggest that the cloud tore through the sun's atmosphere at speeds as high as 3750 km/s. That would make this a very fast moving storm, and likely to reach Earth before the weekend. Auroras are definitely in the offing. Stay tuned for a more detailed forecast in the hours ahead. Aurora alerts: text, voice