[Current solar image with circled area showing the active sunspot region that produced a solar flare on Tuesday; courtesy spaceweather.com]
An active sunspot region officially called AR2158 erupted on Tuesday, September 9th, producing an explosion that lasted more than 6 hours. This long duration solar flare peaked with a classification of M4 (medium-sized) on the intensification scale for solar storms. Long-duration solar flares tend to produce bright coronal mass ejections (CMEs) and this one was no exception. The Solar and Heliospheric Observatory (SOHO) observed a CME racing out of the blast site at nearly 1000 km/s (2.2 million mph; see video). NOAA's solar wind model is forecasting this CME to deliver a glancing, but potent blow to earth’s magnetic field by early on Friday, September 12th (see video). This could result in beautiful auroras visible late tomorrow night/early Friday across the northern tier of the US so sky watchers should be on alert. One final note, active sunspot region AR2158 will be in a position that is directly facing the Earth over the next few days; consequently, any additional ejections can result in an eventual direct impact on the Earth's upper atmosphere.