http://www.spaceweather.com

GEOMAGNETIC STORM WARNING: An explosion on the Sun today triggered a solar proton storm around our planet and hurled a bright coronal mass ejection (CME) into space. Although the fast-moving (~1100 km/s) CME was not squarely Earth-directed, it could deliver a glancing blow to Earth's magnetosphere as early as Dec. 28th Universal Time - that is, Thursday night for North Americans, Friday morning for Europeans. NOAA forecasters estimate a 10% chance of severe geomagnetic storms at middle latitudes when the expanding cloud sweeps past Earth. Sky watchers along the northern tier of US states (and similar latitudes) should be alert for auroras during the nights ahead.

THE MOON AND SATURN: If you find yourself outdoors aurora watching before dawn on Friday morning, look also for a close encounter between the nearly-full Moon and Saturn. The Moon will completely hide the ringed planet from observers in North America. Visit SpaceWeather.com for details.

http://www.spaceweather.com