Alert – Proton Event 100 MeV Integral Flux exceeded 1 pfu issued on July 30

A Proton Event 100 MeV Integral Flux exceeded 1 pfu Alert was issued by NOAA SWPC on July 30, 2026, at 18:33 UTC. This alert signals that the flux of high-energy protons at 100 MeV has surpassed the 1 proton flux unit (pfu) threshold, indicating an increase in energetic particle activity in Earth’s near-space environment.

Proton events of this nature can potentially affect spacecraft operations and communications in high-latitude regions, increase radiation exposure for astronauts, and may result in minor impacts to high altitude flight routes. The alert relates specifically to the 100 MeV integral proton flux and does not necessarily correspond to a Solar Radiation Storm event on the official NOAA Space Weather Scales unless further thresholds are exceeded.

According to the latest SWPC Forecast Discussion, solar activity was at low levels with the largest observed flare being a C3.8 from Region 4498 at 06:06 UTC on July 30, 2026. No direct association with significant solar flares or Earth-directed coronal mass ejections (CMEs) was reported in the forecast. The ongoing proton event may be related to minor solar activity but no specific triggering solar event was highlighted in official reports.