A coronal mass ejection (CME) struck Earth's magnetic field today, Oct. 24th, at approximately 1800 UT (02:00 pm EDT) setting the stage for a possible geomagnetic storm. High-latitude sky watchers should be alert for auroras. Storm alerts: text, voice.

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© Rob Stammes"The expected solarwind shockwave arrived on my instruments at 18.35 UTC.The sky is clear and there is beautiful northern light."
Update #1: Analysts at the Goddard Space Weather Lab say the CME impact caused a strong compression of Earth's magnetic field, allowing the solar wind to penetrate all the way down to geosyncronous orbit for a brief period between 19:06 UT and 19:11 UT. Earth-orbiting spacecraft could have been directly exposed to solar wind plasma during that time.

Update #2: Strong ground currents have been detected in Norway.