NOAA's Space Weather Prediction Center has issued a strong G3 geomagnetic storm warning for June 4 through to June 5, as multiple coronal mass ejections (CMEs) barrel toward Earth. Forecasters say some of the incoming eruptions may merge before arrival in a phenomenon known as a "cannibal CME," which could further intensify the storm's impact on Earth.
This is great news for aurora chasers, as during G3 geomagnetic storm conditions auroras can become visible in mid-latitudes as far south as Illinois and Oregon, according to NOAA.
The incoming storms were launched by a series of powerful eruptions from the active sunspot region 4455, which fired off an M9.3 flare, an M7.7 and an X1-class flare all within 24 hours of each other. NOAA forecasters anticipate the resulting CMEs to arrive at Earth from mid-to-late June 4 through June 5.
When will the northern lights be visible?
The best time to look for the northern lights will be after dark on June 4 into the early hours of June 5.
According to NOAA forecasters, the strongest geomagnetic activity is expected during the evening and overnight hours, with G3 (strong) conditions possible between 2 p.m. and 5 p.m. EDT (1800-2100 GMT) and again between 8 p.m. and 11:00 p.m. EDT (0000-0300 GMT June 5).
Moderate G2 storm conditions are expected outside these peak periods.
However, space weather forecasts remain uncertain. Scientists are tracking the arrival of multiple CMEs that are expected to reach Earth in quick succession and some may merge before arrival in what is known as a "cannibal CME." Because of this complex setup, the timing and intensity of the storm could shift by several hours in either direction.
For real-time forecasts based on your location, consider using a space weather app. A great option is "My Aurora Forecast & Alerts" (available for iOS and Android). For a deeper dive into space weather conditions, "Space Weather Live" is another excellent choice (available for iOS and Android)
