The forecast for this week’s northern lights display has been significantly upgraded, with NOAA’s Space Weather Prediction Center now warning that strong to severe geomagnetic storms could now develop on Thursday, June 4, and continue into Friday, June 5, as multiple coronal mass ejections slam into Earth’s magnetic field.
CMEs are clouds of superheated gas and magnetic fields blasted into space by the sun in the wake of solar flares.
Skywatchers in northern U.S. states are advised to get outside and look north if skies are clear as it gets dark across North America. An 82%-lit waning gibbous moon will rise in the east after midnight and brighten the night sky, potentially interfering with faint aurora.
Aurora Tonight: Alert Updated
Earlier forecasts suggested the strongest aurora activity would occur primarily on Friday. However, NOAA’s latest space weather outlook indicates that G2 (Moderate) and G3 (Strong) geomagnetic storms are likely in North America on Thursday afternoon and evening, with a chance of isolated G4 (Severe) conditions at the peak of the event at night.
In its latest forecast discussion, NOAA said: “Geomagnetic field conditions are expected to escalate rapidly from quiet to active, reaching up to G3 (Strong) geomagnetic storming levels mid-to late on 04 June and persisting into 05 June in response to the multiple CME arrivals.”
Forecasters added that “there is a chance for isolated periods of G4 (Severe) geomagnetic storming during the peak of the multi-CME passage over 04-05 June.”
Significant changes can occur with little warning, and the most reliable forecasts often come only 30 minutes before peak activity.
Northern Lights Tonight: NOAA Upgrades Forecast
The upgraded forecast follows the detection of multiple Earth-directed CMEs launched from the sun on June 3 and June 4. When multiple CMEs travel through space in close succession, they can interact and intensify one another, a phenomenon sometimes referred to as a “cannibal CME.”
NOAA’s latest three-day forecast now predicts Kp values reaching 6.33 (G2) between 15:00 and 18:00 UTC on June 4, rising to 6.67 (G3) between 18:00 and 21:00 UTC. Those periods correspond to the afternoon and evening across North America, potentially setting the stage for a widespread aurora display after dark.
Exact timings are typically unreliable, and space-weather forecasts often change rapidly. A useful way to see what may soon become visible in North America is to check aurora webcams around the world as darkness falls.
Northern Lights Alert: Where To See Aurora Tonight
A G3 geomagnetic storm can push the northern lights well into the northern U.S. If isolated G4 conditions develop, the northern lights could become visible much farther south, down to mid-latitudes, particularly where skies remain clear, and light pollution is low.
The states with the best viewing prospects remain Washington, Idaho, Montana, Wyoming, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, New York and Maine. Additional opportunities may extend into Oregon, Nebraska, Iowa, Illinois, Indiana, Ohio, Pennsylvania, Massachusetts, Connecticut, Rhode Island, Vermont and New Hampshire.
Aurora watchers should continue monitoring real-time space weather updates — such as Space Weather Live and apps like Aurora Now, My Aurora Forecast and Glendale Aurora — because the exact intensity of the display will depend on the orientation of the solar wind’s magnetic field as the CME complex arrives.
Northern Lights Forecast: Understanding Intensity
Aurora-chasers frequently use the Kp index to predict the intensity of a geomagnetic storm, but for aurora displays, the crucial factor will be the orientation of the interplanetary magnetic field embedded within the solar wind. If its north-south component, known as Bz, turns southward (negative Bz), energy from the solar wind can couple much more efficiently with Earth’s magnetic field, allowing geomagnetic activity to intensify rapidly. A sustained southward Bz of −5 nT or stronger usually signals an imminent display of aurora.
Observers in northern U.S. states and much of Canada are on the cusp of a seasonal challenge — in the lead-up to the June solstice, nights become very short, with twilight persisting for much of the night. That limits darkness and makes aurora more difficult to see — even if geomagnetic conditions become favorable.
Wishing you clear skies and wide eyes.