Despite a great forecast for northern lights last night, Thursday, June 4, the powerful geomagnetic storm forecast to be triggered by multiple coronal mass ejections failed to produce widespread aurora displays in North America.
NOAA’s Space Weather Prediction Center had warned that strong geomagnetic storms were likely and that isolated severe storm conditions were possible during the peak of the event.
It’s likely that the trio of Earth-directed CMEs (clouds of superheated gas and magnetic fields blasted into space by the sun in the wake of solar flares) will arrive in daylight, with any intense geomagnetic activity produce unscreen auroras.
However, space weather prediction is hard — and timings are frequently way-off. So the good news for skywatchers is that the show may not be over. There’s still a chance that the northern lights could make another appearance tonight — Friday, June 5 — before geomagnetic conditions gradually subside.
Northern Lights Forecast For Tonight
Geomagnetic storm conditions could continue into tonight as the effects of the CME arrivals persist.
According to NOAA’s forecast discussion, “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 also noted 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.”
Although forecasters expect geomagnetic activity to gradually weaken, uncertainty remains high. The U.K. Met Office said that “activity may begin to ease on Day 2 (05 June); however, confidence in this trend remains low due to the possible influence of the second CME,” suggesting additional aurora displays remain possible if solar-wind conditions remain favorable.
While the strongest activity may already have occurred, geomagnetic storms often fluctuate significantly as solar-wind conditions change. Additional auroral displays remain possible if the interplanetary magnetic field turns southward, allowing energy from the solar wind to couple efficiently with Earth’s magnetic field.
Significant changes can occur with little warning, and the most reliable forecasts often come only 30 minutes before peak activity. A handy way to see what may soon become visible in North America is to check aurora webcams around the world as darkness falls.
Where The Northern Lights Could Be Visible Tonight
The best chances remain across northern-tier states including Washington, Idaho, Montana, Wyoming, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, New York and Maine. Northern U.S. states will always have the best chance of seeing aurora.
If geomagnetic activity spikes considerably, the aurora zone could also extend farther south into Oregon, Nebraska, Iowa, Illinois, Indiana, Ohio, Pennsylvania, Massachusetts, Connecticut, Rhode Island, Vermont and New Hampshire.
As always, darker skies away from city lights will provide the best opportunity to see faint aurora displays. A light pollution map is a good way of finding a dark sky, but it’s just as important to make sure thee’s no skyglow from a city on the northern horizon (head north from a city, not south).
Why The Aurora Spread So Far South
Geomagnetic activity is being triggered by a series of CMEs launched from the sun on June 3 and June 4. When multiple CMEs arrive at Earth in close succession, their effects can reinforce one another, increasing the likelihood of strong geomagnetic storms and expanding the auroral oval farther from the poles.
NOAA’s forecast called for G2 (Moderate) and G3 (Strong) geomagnetic storm conditions, with the possibility of isolated G4 (Severe) intervals. At those levels, the northern lights can become visible much farther south than normal, particularly when skies are clear and observers have an unobstructed northern horizon.
How To Check Aurora Conditions In Real Time
Space-weather forecasts can change rapidly, and the most reliable aurora predictions often come only minutes before activity peaks. Aurora watchers should monitor real-time solar wind data and aurora forecasts throughout the evening. Useful resources include aurora webcams, Space Weather Live and popular forecasting apps such as Aurora Now, My Aurora Forecast and Glendale Aurora. The exact intensity of the display will depend on the orientation of the solar wind’s magnetic field as the CMEs arrive.
One challenge for observers is the approaching June solstice. Nights across the northern U.S. and Canada are becoming increasingly short, limiting the hours of darkness available for aurora viewing. On Friday, a 73%-lit bright waning gibbous moon will rise well after midnight, brightening the sky and potentially washing out fainter displays.
Wishing you clear skies and wide eyes.
