Experts have indicated that we are entering an active solar cycle now and incidents like this will increase with frequency and intensity in the coming months.
Scientists with the National Weather Service’s Space Weather Prediction Center (SWPC) have downgraded the activity forecast for today, downgrading the possibility of a Strong (G3) event down to a Minor (G1) event. As a result, a variety of impacts that could have happened with a stronger event are no longer likely; this also means the aurora shouldn’t be visible too far south tonight.
According to the SWPC, the December 7 coronal mass ejection (CME) did indeed arrive on Earth as forecast. An interplanetary shock was detected last night at 8:32 pm ET, showing the CME did impact the Earth. However, the magnetic strength of this storm was less than the peak potential that could have initiated a G3 (Strong) geomagnetic storm as it arrived at Earth. Therefore, SWPC forecasters are downgrading to G1 (Minor) storm Watches for the remainder of today and tomorrow.
A coronal mass ejection, also known as “CME” for short, is responsible for this event. A coronal mass ejection is a significant release of plasma from the solar corona, often following solar flares in solar wind. These huge explosions of plasma originate from highly twisted magnetic field structures on the Sun. When these explosions occur from active sunspot regions on the Sun, it is not uncommon to see them associated with large solar flares. Some fast CMEs can reach the Earth in little as 14 hours, while others may take several days. According to the SWPC, “the first sign of a CME hitting the Earth environment is the plasma density jump due to the shock wave’s passage.” Forecasters use what is known as a coronagraph, which blocks the extremely bright disk of the Sun, so they are able to determine the CME’s size, speed, direction and density.
If conditions are just right, a CME could have significant impacts to earth ranging from radio communication failures, issues with the electrical grid and power generating systems, and navigation system problems. It can also trigger the aurora to appear much further away from the poles than it usually does.
While typically known for their weather forecasts, the National Oceanic and Atmospheric Administration (NOAA) and its National Weather Service (NWS) is also responsible for “space weather.” While there are private companies and other agencies that monitor and forecast space weather, the official source for alerts and warnings of the space environment is the Space Weather Prediction Center (SWPC). The SWPC is located in Boulder, Colorado and is a service center of the NWS, which is part of NOAA. The Space Weather Prediction Center is also one of nine National Centers for Environmental Prediction (NCEP) as they monitor current space weather activity 24/7, 365 days a year.