Overview
- NOAA’s Space Weather Prediction Center reported an S4 severe solar radiation storm, the strongest since 2003, alongside G4 geomagnetic storming.
- G4 conditions were first recorded at 2:38 pm EST after the CME shock arrival, with auroras observed across large parts of the U.S., the UK and mainland Europe.
- Forecasts indicated auroral visibility extending unusually far south in North America, potentially to Alabama and northern California, depending on local sky conditions.
- Agencies notified grid, aviation and satellite operators, and early reports such as from New Zealand’s NEMA and Transpower cited geomagnetically induced currents within manageable limits.
- Observers noted very fast solar wind near 1,070 km/s and a following coronal hole, factors that could sustain or amplify geomagnetic activity into Tuesday.