The National Weather Service’s Space Weather Prediction Center (SWPC) has issued a “severe geomagnetic storm watch,” the first such watch issued in nearly 20 years.
According to the SWPC, this marks the first watch issued by the department since Jan. 2005. The watch comes after multiple earth-directed coronal mass ejections (CME’s) were observed by forecasters this week.
At least five CME’s have been observed in recent days, and the particles could begin arriving to Earth by Friday afternoon, according to officials. It’s expected that the CME’s could continue to arrive through Sunday, marking for an “unusual event.”
Only three “severe” geomagnetic storms have been observed since the current solar cycle began in Dec. 2019. The last G4 storm hit Earth in March, and the last G5 storm hit in Oct. 2003, causing power outages in Sweden, according to SWPC.
CME’s are “large expulsions of plasma and magnetized-particles from the Sun’s corona,” according to the SWPC. Those ejections can expand in size as they approach Earth, and can cause geomagnetic storms when they arrive.
In a geomagnetic storm, the particles ejected by the sun cause disturbances in Earth’s magnetosphere. Particularly strong storms can impact the Earth’s ionosphere, adding energy in the form of heat that can “increase the density and distribution of density in the upper atmosphere, causing extra drag on satellites in low Earth orbit,” according to the SWPC.
As a result, disruptions in navigation systems, radio communications and power grids are all possible, though it is unclear if the approaching storm will be strong enough to yield those impacts.
Another potential impact that could occur is a much-more vibrant Northern Lights spectacle, which can be seen as far south as Tennessee or even Alabama, according to officials.
Unfortunately for residents in Illinois, showers are expected to impact the Chicago area late Friday and into Saturday, likely spoiling the show that evening.
In addition, space weather forecasts can change dramatically in a matter of hours, with officials providing additional updates as the weekend draws closer.