The Sun released a coronal mass ejections (CME), a sudden burst of energy, on Thursday morning. This happened as magnetic fields above a sunspot twisted to the breaking point, hurling several billion tons of electrically charged gas out into space. That sunspot was facing Earth, promoting NOAA’s Space Weather Prediction Center to issue a G3 (strong) Geomagnetic Storm Watch on Friday.
This is forecasted to bring higher auroral activity deeper into the continental United States.
As those charged particles arrive, they will follow the magnetic lines of the magnetosphere, which surrounds the Earth like a doughnut, funneling that energy down at the poles. The stronger the solar storm, the deeper those charged particles make their way into that doughnut, the more likely those in lower latitudes, like here in Raleigh, are to see aurora.
While it takes sunlight about 500 seconds to reach Earth, CMEs travel much slower, taking several days to arrive. Observations from NASA’s Solar Terrestrial Relations Observatory (STEREO) show this CME is traveling at about 800 km/sec which would put its arrival late Saturday night into Sunday morning.
Aurora activity is to be most visible from the Pacific Northwest, across the Upper Midwest, through New York and New England, visible low on the horizon as far south as Northern California, Oklahoma, Tennessee and North Carolina.
Aurora viewing tips
Look to the northern horizon Saturday night into Sunday. Partly cloudy skies are forecast, so you might be looking through a few holes in the clouds. The best viewing will be under the darkest skies, from about nine minutes after sunset to before moonrise around 1:30 a.m.
Don’t expect the beautiful ribbons of red and green (oxygen molecules) or blue and pink (nitrogen molecules) you may have seen in photos. At least a very strong G5 solar storm is needed to produce significant auroral activity in our skies. But G3 storms have produced a noticeable green hue to the northern skies in the past.
We’ll know more about what to expect and when on Saturday afternoon as the CME reaches instruments aboard NOAA’s Deep Space Climate Observatory (DSCOVR) positioned between the Earth and Sun, another 4 Earth-Moon distances beyond the Moon.
The most up to date forecasts are also available from NOAA’s Space Weather Prediction Center which are updated every 30 minutes.