Aurora Borealis watch as geomagnetic storm may arrive around March 19

The passing solar storm could spark bright displays of the aurora borealis across Canada this week after an M2. 7 flare on March 16 launched a coronal mass ejection heading toward Earth.

What Is the Current State of Play?

The Solar Dynamics Observatory captured the M2. 7 flare on March 16, and NASA’s ENLIL model showed the resulting coronal mass ejection travelling toward Earth with an estimated arrival around 12 UTC on March 19. NOAA’s Space Weather Prediction Center issued a G2 (moderate) geomagnetic storm watch for the early hours of Thursday, March 19. The SWPC forecast calls for G1 (minor) storm levels to begin around 11 p. m. Wednesday night through 2 a. m. Thursday morning EDT, followed by G2 (moderate) levels from 2 a. m. through 8 a. m. EDT.

What Happens When Aurora Borealis Arrives?

When the coronal mass ejection reaches Earth it is expected to disturb the planet’s magnetic field and trigger geomagnetic storm conditions that favour auroral activity. The forecast favours central and western regions of Canada for the strongest displays. The event’s timing remains uncertain: an earlier arrival could shift the brightest displays farther east and into Wednesday night, while a later arrival could push peak activity into daytime hours on Thursday and reduce viewing opportunities.

• Forecasted storm timing (EDT): G1 ~ 11 p. m. Wednesday to 2 a. m. Thursday; G2 ~ 2 a. m. to 8 a. m. Thursday.
• Favoured viewing: central and western regions of Canada for the strongest auroras.
• Timing uncertainty: could arrive sooner (brighter auroras earlier, more east) or later (peak during daylight, missed night viewing).
• Historical note from the forecast: displays close to the March Equinox can be especially bright and colourful.

What Regions Could See Clear Skies?

Sky conditions noted in the forecast were mixed. In the eastern half of the country, clear-sky pockets include Northwestern Ontario and a band across eastern New Brunswick, Prince Edward Island, and the western half of mainland Nova Scotia for the morning in question. In the west, the best chances of clear skies appear to be southern Manitoba, southwestern Saskatchewan, southern Alberta, and the interior and central regions of British Columbia. Overall, observers should expect viewing odds to vary by location and by the actual arrival time of the coronal mass ejection.

Timing remains the central uncertainty: if the coronal mass ejection arrives as modeled the early hours of March 19 could deliver notable night-time auroras in central and western Canada, but an earlier or later arrival would shift the geography or the viewing window for the aurora borealis.