The NOAA’s Space Weather Prediction Center is warning of severe geomagnetic storms and brilliant auroras from Thursday, June 4, into Friday, June 5, driven by volatile solar activity, as coronal mass ejections (CMEs) are set to impact Earth’s magnetic field.
These events are being tracked and monitored, with an eye not just on the beauty of auroras in the night sky but also on potential hazards to technological infrastructure from electrical interference.
Residents of Canada and the northern US will have the best views, but there is a chance that isolated pockets of extreme activity will push visibility much further south.
Solar Eruptions Race Toward Earth
The extreme solar activity originated in the Sun’s unstable sunspot region 4455, which faces Earth, on June 2. Region 4455 is an anti-Hale spot, meaning it carries reverse polarity, making it extremely volatile. The first solar flare, rated M9.3, launched at 9:36 PM EST, with activity continuing overnight.
At 3:00 AM EST on June 3, an M7.9 flare erupted, followed at 7:28 AM EST by an extremely powerful X1 flare, the highest classification for such events.
These solar flares then send clouds of superheated gas and magnetic fields, known as CMEs, into space. In this case, these powerful outbursts were sent on a course toward Earth.
With the proximity of these CMEs to one another, there is also a chance for a “cannibal CME” to occur, which occurs when multiple CMEs making their journey to Earth in rapid succession can interact along the way, growing in intensity.
When these CMEs reach Earth, they can produce beautiful auroras, and also major interference affecting electrical systems such as GPS and communications technologies. With our ever-increasing reliance on such infrastructure, CMEs have become a greater concern in recent decades.
A Changing Aurora Picture
Forecasts initially indicated that Friday would see most of the activity, but now activity is expected to peak on Thursday night, with a chance of severe G4 geomagnetic storms in some areas. As the CMEs arrive, NOAA says the events “could escalate rapidly from quiet to active,” and major changes in the forecast can occur until very close to the event.
Scientists use the Planetary K-index, also known as the Kp-index, to grade the effect of geomagnetic impacts on the Earth’s magnetic field on a scale of 0 to 9. NOAA is forecasting a 6.33 Kp value for CME activity between 11 AM EST and 2 PM EST, corresponding to a G2-level event, before rising to a 6.67 Kp G3 event between 2 PM EST and 5 PM EST.
Although the peak will arrive before dark, these events will prepare the way for Auroras once the Sun sets. According to NOAA, straggling outlier CMEs could appear as late as 8 hours after the main activity.
Aurora Viewing Opportunities
This evening, skywatchers in the northern United States may be treated to a show, though after midnight, the gibbous moon rising in the east may drown out the colors with its light.
The severity of tonight’s events will have a major impact on how bright the auroras are and how far south they are visible. Under the expected G3 conditions, the northern U.S. will have a good view, but if the isolated G4 conditions do develop, that could push visibility down into the mid-latitudes. Local conditions will also play a major role, with visibility extended in areas with minimal light pollution and clear skies.
A full list of states with a likely chance of seeing auroras this evening, according to Forbes, includes Washington, Idaho, Montana, Wyoming, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, New York, and Maine.
Additional opportunities may extend into Oregon, Nebraska, Iowa, Illinois, Indiana, Ohio, Pennsylvania, Massachusetts, Connecticut, Rhode Island, Vermont, and New Hampshire. Some states, such as New York and Vermont, are reporting clear skies this evening, offering optimal viewing conditions.
With the best predictions coming within about a half-hour of activity, skywatchers are advised to continue paying attention to real-time space weather updates for more information, such as NOAA’s 30-minute forecast page.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.