More on this AURORA WATCH: A solar wind gust hit Earth's magnetic field on April 15th, sparking a G1-class (Kp=5) geomagnetic storm. Skies over Finland lit up with a beautiful mix of green and purple:
We had a good display for about an hour," says photographer 'JTbo' of Saarijarvi, Finland. "This spring has been something special as the auroras seem to be very strong." They could become stronger in the nights ahead. A coronal mass ejection (movie) blasted into space by an erupting prominence on April 13th could deliver a glancing blow to Earth's magnetic field on or about April 17th. (Note: This supercedes earlier estimates of an April 15th arrival.) High-latitude sky watchers should remain alert for auroras.