Where and when will the Northern Lights be visible? The Northern Lights may be seen this week in the continental U.S. after space weather forecasters predicted favorable geomagnetic storm conditions.
Only those in dark skies -- away from urban light pollution -- can likely see anything. Light pollution, which has reached critical levels, drastically affects the visibility of aurora.
The possibility of displays of the aurora borealis at southerly latitudes comes after a spate of solar flares and coronal mass ejections supercharged the solar wind. Ib their wake, the National Oceanic and Atmospheric Administration's Space Weather Prediction Center released a Northern Lights forecast for this week. It states that the Northern Lights will likely be bright on Tuesday and Thursday night over some northern and upper Midwest states from New York to Idaho.
States where the lights may be visible include Washington, Montana, Minnesota, Iowa, Wisconsin, Michigan, New York, Vermont, and Maine.
A G2 geomagnetic storm is being forecast, though take that with a pinch of salt -- it could, in practice, turn out to be either a weaker G1 or a stronger G3, particularly in September when the "equinox effect" takes hold.
NOAA predicts geomagnetic storm conditions may continue through Thursday, though space weather is unpredictable and the forecast can change quickly. Skywatchers are advised to check NOAA's aurora view line, which is available for tonight and tomorrow night, and its 30-minute forecast and X account, where the latest forecasts are posted. For those in the U.K., Lancaster University's AuroraWatch website is invaluable.
The predicted displays of aurora borealis this week have a Kp index of 5. Here's how the Kp index works and what you'll see, according to NOAA:
Although exceptional displays can sometimes be seen even from U.S. cities, that's rare. If a display is predicted for the U.S., avoiding light pollution is imperative. Suggested locations are an International Dark Sky Place (U.S./worldwide), a Dark-Sky Preserve (Canada) or a Starlight Reserve (Spain). Or consult a light pollution map -- anywhere with a dark northern horizon is a good location.
However, the best and most reliable way to see the Northern Lights is to travel north, in the northern hemisphere, between September and March (when there's sufficient darkness). That means Alaska, northern Canada and northern Scandinavia (Norway, Finland, Sweden, and Iceland).
Solar activity is currently at a 23-year high, with May 10's extreme G5 geomagnetic storm being the most severe in the past two decades and possibly for hundreds of years. According to experts, the sun is approaching "solar maximum" this year or next. SWPC's latest forecast is for it to happen between August 2024 and January 2025.
The sun has an 11-year cycle during which its magnetic activity waxes and wanes. Its level is calculated daily by counting sunspots. Sunspots are magnetic disturbances on the sun's surface that can be as big as Earth. The number of sunspots on any day indicates how magnetically active the sun is.
The number of solar flares and CMEs has gradually increased over the last few years. The currently frequent and powerful geomagnetic storms will likely continue through until 2026.