On Monday evening, observers had the opportunity to witness a moderate northern lights display. For those who missed it, there is a chance of another sighting tonight, as a more potent geomagnetic storm is predicted by the U.S. National Oceanic and Atmospheric Administration’s Space Weather Prediction Center (SWPC).
The sun has been quite active, displaying numerous sunspots on its surface that can trigger solar flares. These flares, which emit bursts of electromagnetic radiation, have the potential to disrupt radio transmissions on Earth. Often, these solar events are followed by coronal mass ejections (CMEs), where solar particles interact with the Earth’s magnetic field to produce stunning northern lights, or aurora borealis.
In this instance, two CMEs were released from the sun on August 30 and are heading towards Earth. According to Tamitha Skov, a space weather physicist and professor at Millersville University in Pennsylvania, the second eruption, initially underestimated, turned out to be more powerful upon closer examination.
Monday’s geomagnetic storm reached a G2 level on a scale of one to five, with the SWPC anticipating a G3 storm for Tuesday night.
Forecasting auroras is notoriously challenging, making it uncertain whether there will be a show tonight. However, several apps such as Aurora Alerts and Aurora Now can indicate if the northern lights are visible in your area.
The remarkable displays of the northern lights on May 10, 2024, and Oct. 10, 2024, which reached G5 storms despite initial forecasts of G3 or G4, serve as examples of the difficulty in accurately predicting these events.
The current storm forecast involves the impact of two solar storms on Earth, with the first hitting on Monday and the second expected on Tuesday. Anticipating severe storm conditions at high latitudes, NOAA foresees a 50% chance of a strong geomagnetic storm over the next 24 hours for cities in mid latitudes, increasing to 85% for high latitudes.
Various factors influence the visibility of auroras, including the speed of the solar wind and the position of the auroral oval, which determines where the lights will be visible.
NOAA employs the Kp index, ranging from one to nine, to measure the strength of geomagnetic storms. A Kp index of 6 or higher is typically needed for auroras to be visible in mid-latitudes. As of now, the Kp index is at four, with the auroral oval extending into northern Europe.
Hopefully, Canadians will experience a spectacular aurora display if the magnetic field of the storm is favorably aligned, even reaching mid-latitudes, as suggested by Skov.