Overview
- A powerful X1.1 flare from sunspot region AR4479 erupted on Tuesday, June 30 and its X-ray burst reached Earth in about eight minutes, triggering an official R3 high-frequency radio blackout over daylight North America.
- The flare launched a coronal mass ejection that NOAA later judged to have at least a partial Earth-directed component and issued a Moderate (G2) geomagnetic storm watch for July 3.
- Forecasts remain conditional because the strength of geomagnetic effects depends on the CME's embedded magnetic field orientation, with a southward-directed field more likely to couple with Earth's magnetosphere and produce stronger storms and brighter auroras.
- The Sun continued to erupt after the X-flare, producing multiple M-class flares and additional CMEs that have complicated modeling of arrival times and raised chances of geomagnetic activity over the July 3–4 interval.
- NOAA, NASA and satellite operators are monitoring the situation because geomagnetic storms can disrupt high-frequency radio, degrade navigation signals, affect satellites and spacecraft electronics, increase astronaut radiation risk, and at G2 levels push auroras farther south under dark clear skies.