NOAA's Space Weather Prediction Center has issued a G1 minor geomagnetic storm watch, and the Northern Lights aurora borealis forecast points to activity overnight tonight into Thursday morning. The leading edge of a coronal hole high speed stream is expected to arrive at Earth around 11 p.m. EDT, with increased aurora activity likely to last until 5 a.m. EDT tomorrow.
Scott Sutherland and the timing
Scott Sutherland tied the forecast to the WSA-Enlil computer model graphic for late on Sep. 23, 2026, which showed the stream arriving at Earth. That timing narrows the viewing window for people watching from Canada: the display is most likely after dark, then through the pre-dawn hours when skies are darkest.
The watch matters because a coronal hole high speed stream can break up the normal flow of the solar wind and push auroral activity farther from the poles. The Sun's coronal holes are large gaps in the solar corona that send fast streams of particles into the solar system, and when one sweeps past Earth it can spark auroras that reach into the mid-latitudes.
Canada and the Prairies
The strongest displays from a G1 geomagnetic storm tend to stay farther north in the eastern half of the country, including Labrador, northern Quebec, and northern Ontario. For this event, though, the best viewing is likely in the central Prairies, where Manitoba has the clearest stated window from 10 p.m. through 4 a.m. CDT.
Saskatchewan and Alberta also sit in the forecast zone, with the stated viewing window running from 9 p.m. through 3 a.m. MDT/CST. That creates a split forecast: the most intense aurora is favored farther north, while the most practical viewing window for this specific event is centered over the Prairies.
People in Canada watching for auroras should look for the overnight hours rather than the evening headline. If skies stay dark and clear, the strongest chance comes from the period just after the stream reaches Earth, not from the first sign of daylight.
Earth and the Sun
Auroras appear around the north and south poles of Earth as Earth's geomagnetic field traps particles from the solar wind and funnels them down into the atmosphere. This forecast also comes during a period when aurora displays can be enhanced by equinox cracks, which can help brighten or widen the lights without changing the basic source of the storm.
The immediate question is how strong the display will be once the stream reaches Earth around 11 p.m. EDT. For now, the watch gives people in Labrador, Quebec, Ontario, Manitoba, Saskatchewan, and Alberta a narrow overnight window to check the sky before dawn.
