Electron 2 MeV Integral Flux Alert issued on December 20

An Electron 2 MeV Integral Flux Alert was issued on December 20, 2025, at 04:59 UTC by NOAA’s Space Weather Prediction Center. The alert continues from December 17, 2025, after electron flux levels surpassed the threshold of 1,000 particles per square centimeter per second per steradian (pfu). The most recent maximum, recorded the previous day, reached 3,239 pfu.

Potential impacts from this elevated flux include significant charging of satellite systems, which increases the risk to satellite operations and onboard electronics. These conditions require satellite operators to remain vigilant to potential anomalies or disruptions resulting from enhanced energetic particle activity.

According to the latest forecast discussion, the greater than 2 MeV electron flux reached high levels, with a peak flux of 3,240 pfu observed on December 19, 2025. Elevated electron flux levels are expected to persist through December 21 before returning to normal to moderate levels as a corotating interaction region approaches.