Alert – Electron 2 MeV Integral Flux exceeded 1,000 pfu on December 27

An alert was issued for Electron 2 MeV Integral Flux exceeding 1,000 pfu on December 27, 2025. The alert, originally continuing from December 21, 2025, was announced by the NOAA Space Weather Prediction Center. The maximum observed 2 MeV electron flux reached 8,194 pfu yesterday, highlighting persistent high levels over several days.

Potential impacts of this alert include significant charging of satellite systems, leading to increased risk for those systems in orbit. Operators of satellite infrastructure are advised to assess and implement appropriate mitigation measures, as episodes of high electron flux can affect functionality and longevity by causing surface and internal charging events.

According to the latest forecast discussion issued by NOAA SWPC, the greater than 2 MeV electron flux is expected to remain at high levels on December 27 and December 28, before declining to normal to moderate levels by December 29. Solar activity was reported as low, and there have been no Earth-directed coronal mass ejections observed in available data.