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Auroras Light Up Much of U.S. as NOAA Warns of G4 Geomagnetic Storm Today

A faster CME expected around midday could intensify disturbances to satellites, GPS and power systems.

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The aurora borealis as seen from Parker on Nov. 11, 2025. The northern lights were visible across metro Denver because of a severe geomagnetic storm, according to the Space Weather Prediction Center. (Photo by Lauren Penington/The Denver Post)
The Northern Lights glow above a sign at Mount Tamalpais State Park in Mill Valley, Calif., Thursday, Oct. 10, 2024. The phenomenon could be visible again Tuesday and Wednesday in California.
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Overview

  • NOAA’s Space Weather Prediction Center has a G4 (severe) storm watch in effect for Nov. 12, following a G2 watch on Nov. 11 and ahead of a G3 watch on Nov. 13.
  • Five X‑class flares since Nov. 9, including an X5.1, launched three CMEs; two arrivals fueled overnight auroras on Nov. 11–12 with a third, stronger CME forecast around midday Nov. 12.
  • Auroras were photographed across the U.S., with reports as far south as Alabama, New Mexico, Arizona, South Carolina and New Jersey, and National Weather Service offices sharing images.
  • Forecasts indicate potential visibility into the northern half of the country, possibly reaching northern California and the Midwest, with the best chances late evening through early morning depending on clouds and CME orientation.
  • SWPC cautions that severe storms can degrade HF radio and GPS, affect satellites and trigger grid voltage control issues, and notes timing updates come from upstream satellites with roughly 15–60 minutes’ lead time.