ELECTRIC-BLUE CLOUDS: The 2011 noctilucent cloud (NLC) season has begun. For the past few nights, observers in northern parts of Europe have spotted velvety, electric-blue tendrils rippling across the sunset sky. NLCs are a summertime phenomenon first reported by polar observers in the 19th century. In recent decades, for reasons no one fully understands, the clouds have intensified and spread as far south as Utah and Colorado. Visit today's edition of http://spaceweather.com for photos and observing tips.
CHANCE OF MAGNETIC ACTIVITY: NOAA forecasters estimate a 45% chance of geomagnetic activity on June 4th when an incoming solar wind stream and a CME might deliver a double blow to Earth's magnetic field. High-latitude sky watchers in both hemispheres should be alert for auroras. Aurora alerts: http://spaceweatherphone.com (voice) or http://spaceweathertext.com (text).