Northern Lights Expected to Make an Appearance Across Canada May 31

A brilliant show of the aurora borealis near Yellowknife, N.W.T., is shown in the night sky on March 8, 2012. Bill Braden/The Canadian Press

The night skies may put on a celestial show for Canadians May 31 thanks to a geomagnetic storm that is predicted to enhance the Northern Lights.

Government agencies in both Canada and the United States have issued a major geomagnetic storm watch, a phenomenon that can enhance the visibility of the aurora borealis after dusk.

The storm and impending light show marks the second time this month Canadians have had the opportunity to witness the nighttime phenomenon.

A similar but more severe solar storm hit the earth’s geomagnetic field on May 10 bringing about the brightest display of the aurora borealis seen in North America in more than 20 years, according to the Weather Network meteorologist Scott Sutherland.

After a more than two-week interlude on the other side of the Sun, the sunspot region that produces extreme weather in space has rotated back to face the earth. Although the sunspot group “isn’t as big as when we saw it last,” the Weather Network is still expecting it to “pack a punch,” Mr. Sutherland said.

The U.S. government’s National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center has issued a G2 geomagnetic storm watch beginning the evening of May 31. This moderate-level storm is expected to continue through the following morning.

A coronal mass ejection (CME) began the morning of May 29 and “is likely to enhance the earth’s magnetic field late on May 31,” the NOAA said in a press release.

While the brightness of the aurora borealis on May 31 is not expected to match the brilliance of the night skies during the severe geomagnetic storm early this month, both the NOAA and the Weather Network are predicting the Northern Lights will be on display for most of Canada and some northern U.S. states throughout the night.

Space Canada seems less sure about a Northern Lights show being seen in the more southern parts of the country, however. The agency is predicting “active” auroral sightings with “stormy intervals” for only the northern parts of Canada while the southern part of the country can expect “quiet” sub-auroral activity with stormy intervals.

Whether the Northern Lights are active or quiet, clear skies are key to enjoying the show, Mr. Sutherland pointed out. Rural residents are also more likely to see a better display due to less light pollution.

A geomagnetic storm watch is issued when “conditions are favourable for the development of hazardous geomagnetic, and potentially ionospheric, activity that poses a threat to critical infrastructure and technology at or near the earth,” according to Space Canada.

While a storm watch indicates that geomagnetic activity is possible, it “does not mean severe activity is imminent.”

Under the G2 storm, which is expected this evening, there is a chance for high-latitude power systems to experience “voltage alarms” while long-duration storms can cause transformer damage.