Electron 2 MeV Integral Flux Alert issued on August 21

An alert for Electron 2 MeV Integral Flux exceeding 1,000 pfu was issued on August 21, 2026. The threshold was reached at 11:05 UTC, with the alert formally issued by NOAA’s Space Weather Prediction Center at 11:18 UTC. The event was detected by the GOES-19 satellite.

When electron flux levels surpass the 1,000 pfu threshold at geosynchronous orbit, there is an increased risk of spacecraft surface charging, potential anomalies, and deep dielectric charging. These conditions can impact satellite operations and are closely monitored by space weather agencies.

According to NOAA’s latest forecast discussion, the electron flux at geosynchronous orbit was projected to cross the 1,000 pfu threshold on August 21 and remain at high levels through August 23 due to influences from a coronal hole high speed stream (CH HSS). Proton flux values remain at background levels during this period.