Electron 2 MeV Integral Flux Alert issued on June 28, 2026

An Electron 2 MeV Integral Flux Alert was issued on June 28, 2026, by the NOAA Space Weather Prediction Center, indicating that the electron flux at energies greater than 2 MeV exceeded the 1,000 pfu threshold. The alert remains in effect following sustained elevated flux levels since June 26, 2026, with the maximum recorded flux reaching 3,793 pfu on June 27 at 15:25 UTC.

Electron flux events at these levels typically occur during periods of enhanced geomagnetic activity. When 2 MeV electron fluxes exceed the alert threshold, increased charging of satellites in geosynchronous orbit can occur, potentially affecting satellite operations and electronic components. According to the latest measurements, the flux has remained at moderate to high levels for several days and is expected to stay elevated through June 30, 2026.

The elevated electron flux is associated with recent space weather conditions, including the continued influence of a negative polarity coronal hole high speed stream (CH HSS). Solar wind speeds were initially near 675 km/s, decreasing to around 525 km/s, while no new Earth-directed coronal mass ejections were observed. Forecasts indicate that these elevated electron flux levels will likely persist until at least June 30 as CH HSS impacts weaken and new enhancements are possible with anticipated CME arrivals.