Electron integral flux alert issued on May 19, 2026

An alert for Electron 2 MeV Integral Flux exceeding 1,000 pfu was issued on May 19, 2026 at 05:14 UTC by NOAA’s Space Weather Prediction Center. The threshold was first exceeded on May 16, 2026 at 17:40 UTC, as monitored by GOES-19. Yesterday’s maximum electron flux reached 6,667 pfu, indicating sustained elevated levels.

Elevated electron fluxes at geosynchronous orbit can result in increased risk for satellite anomalies, especially in systems not specifically hardened against high-energy electrons. These conditions can also lead to surface charging on satellites and may require operational precautions for sensitive spacecraft outside Earth’s protective atmosphere. The alert is based on the integral electron flux crossing the 1,000 pfu level, referencing NOAA’s operational thresholds for this parameter.

According to the latest forecast discussion, the high levels of electron flux are expected to decrease to normal or moderate levels between May 19 and May 20 as the influence of recent high-speed solar wind streams wanes. Electron flux may return to moderate or high levels again on May 21 if conditions change. The proton flux remains at background levels, and no significant solar activity or Earth-directed CMEs have been observed during this period.