S1 – Minor Solar Radiation Storm Alert issued on November 14

An S1 – Minor Solar Radiation Storm Alert was issued on November 14, 2025, after the 10 MeV integral proton flux exceeded 10 pfu. The alert was released at 09:37 UTC, with the event beginning at 09:20 UTC. This marks a minor level solar radiation storm according to the NOAA Space Weather Scale.

Minor solar radiation storms at the S1 level can result in minor impacts on polar high frequency (HF) radio propagation. This may include brief fading of signals at lower frequencies, especially in polar regions. These disruptions are generally limited in scope and duration.

The latest forecast discussion from the NOAA Space Weather Prediction Center indicates that energetic proton levels had been trending towards nominal in the previous period but have again exceeded the S1 threshold. The forecast notes ongoing monitoring of solar regions, particularly Region 4274, which has demonstrated some flare activity, though the immediate cause of the current S1 event is not attributed to a specific flare in the official discussion.