A restless Earth-facing sunspot unleashed a powerful X-class solar flare on June 30, triggering radio blackouts across parts of North America.
The X1.1 solar flare erupted from sunspot region AR4479, peaking at 4:50 p.m. EDT (2050 GMT) according to NOAA's Space Weather Prediction Center.
The intense burst of X-rays released during the eruption reached Earth in just over 8 minutes, triggering strong (R3) radio blackouts across the daylight side of Earth. This mainly affected high-frequency radio users across parts of North America who may have experienced temporary signal degradation or brief communication outages while the flare was at its strongest.
The eruption also launched a coronal mass ejection (CME) — a huge cloud of magnetized solar plasma hurled into space. Initial observations suggested most of the material was traveling northward, limiting the chances of a significant Earth impact.
However, after further analysis, NOAA's Space Weather Prediction Center issued a Moderate (G2) geomagnetic storm watch for July 3, indicating that at least part of the CME could land Earth with a significant blow.
Will we see the northern lights?
When Earth-directed, CMEs can interact with our planet's magnetic field and spark geomagnetic storms, which can produce dazzling northern lights displays.
A G2-level storm is capable of pushing the northern lights farther south than normal. According to NOAA, auroras could become visible across some northern and upper Midwestern U.S. states, from New York to Idaho, provided skies are dark and clear.
Exactly how impressive the display becomes will depend on the strength of the CME and, crucially, the orientation of its embedded magnetic field when it arrives. If conditions are favorable, the natural light show could provide an extra helping of "fireworks" just in time for the July 4 weekend.
What are solar flares?
Solar flares are sudden bursts of energy released when magnetic fields around sunspots become twisted and reconnect. They are ranked using five classes — A, B, C, M and X — with X-class flares representing the most powerful eruptions.
What are CMEs?
CMEs behave a little differently. Unlike the radiation from a solar flare, which reaches Earth at the speed of light, these clouds of charged particles typically take one to three days to reach us. If they arrive in the right magnetic orientation, they can disturb Earth's magnetic field and trigger geomagnetic storm conditions.
Editor's note: This story was updated at 9:30 a.m. EDT on July 1 to reflect NOAA's latest forecast, including the issuance of a G2 (Moderate) geomagnetic storm watch for July 3 following further analysis of the accompanying coronal mass ejection.