On Sunday August 1, 2010 a small solar flare erupted on the Sun at about 4 am EDT. Associated with this flare was a coronal mass ejection (CME) that was directed towards the Earth, moving at approximately 2.5 million miles an hour.
As defined, a coronal mass ejection is an outflow of plasma from or through the solar corona. CMEs are often, but not always, associated with erupting prominences, disappearing solar filaments, and/or flares. CMEs vary widely in structure, density, and velocity. Earth impacting CMEs can result in significant geomagnetic storms.
As predicted by the NOAA National Weather Service (NWS) Space Weather Prediction Center (SWPC) in Boulder, Colorado, this CME arrived at Earth on Tuesday, August 3 at 12:41 pm EDT, kicking off a small geomagnetic storm.
This geomagnetic activity is expected to continue at least two more days as this event winds down and then Earth is hit with another coronal mass ejection. The SWPC forecast is calling for activity to be strongest on Thursday, August 5.
No significant reports have been received, although there were some reports of amateur (ham) and CB radio signal disruption, which are typical of what is expected even from minor geomagnetic storms.
An increase in auroral activity is expected for northern latitudes for the next few days, including in Alaska and Canada. There are very low probabilities of aurora being visible over the next two to three nights across the far northern tier of the contiguous states, including New England, upstate New York, Michigan, Wisconsin, Minnesota, North Dakota, South Dakota, Montana, northern Idaho and Washington state. Tips on viewing the aurora can be found at http://www.spaceweather.gov/Aurora/index.html .
Click below for Space Weather Prediction Center (SWPC) websites of interest
Space Weather Now - gives a layman's overview of current solar activity and space weather
Today's Space Weather - gives a more technical look at current solar activity and space weather
Auroral activity extrapolated from NOAA Polar Orbiting Satellites
A press release from the Harvard Smithsonian Center for Astrophysics in Cambridge, Massachusetts, which uses the NASA Solar Dynamics Observatory to observe the solar activity.