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X5.1 Solar Flare From AR4274 Triggers R3 Blackout as NOAA Issues G4 Storm Watch

Forecast models point to several Earth-directed CMEs with a risk of merger that could strengthen impacts through Nov. 13.

Overview

  • The flare peaked at 10:04 UTC on Nov. 11, the strongest of 2025 so far, and launched a large Earth-directed coronal mass ejection.
  • NOAA’s Space Weather Prediction Center now forecasts G4 (Severe) geomagnetic storm conditions on Nov. 12 and G3 (Strong) on Nov. 13.
  • Multiple CMEs from Nov. 9–11 are projected to arrive between Nov. 11–13, with forecasters noting a possible “cannibal” merger that could amplify geomagnetic effects.
  • Proton flux climbed to S2 (Moderate) following the X5.1 event, and the flare caused an R3 radio blackout over Europe and Africa on the sunlit side.
  • Potential impacts include degraded HF and GPS, satellite charging and upsets, power-grid voltage control issues, and auroras potentially visible as far south as Alabama and northern California.