Date: 2026 Sep 26 0030 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
Solar activity was low. Low-level C-flare activity was observed from Regions 4534 (N10W76, Cro/beta) and 4536 (N02W53, Dsi/beta), and from a source beyond the west limb. Region 4536 exhibited minor growth while the remaining seven regions were stable or in decay. No Earth-directed CMEs were observed.
Forecast: Solar activity is likely to reach low levels on 26-28 Sep, with a slight chance for an isolated M-flare (R1-R2/Minor-Moderate).Energetic Particle The greater than 2 MeV electron flux was at normal to moderate levels. The greater than 10 MeV proton flux was steady at background levels.
Forecast: The greater than 2 MeV electron flux is expected to be at normal to moderate levels on 26 Sep, before increasing to high levels on 27-28 Sep. The greater than 10 MeV proton flux is expected to persist at background levels through 28 Sep.
Solar wind parameters reflected continued positive polarity CH HSS influences. Total magnetic field strength reached a peak of 10 nT, and the Bz component varied between +6/-10 nT. Solar wind speeds gradually increased from a low of around 400 km/s to a peak near 557 km/s. The phi angle was predominantly positive (away from the Sun).
Forecast: A mildly enhanced solar wind environment is expected to continue on 26-27 Sep as CH HSS influences gradually subside. Background solar wind conditions are expected to return on 28 Sep.
Forecast: The geomagnetic field is expected to reach active levels on 26 Sep, followed by quiet to unsettled levels on 27 Sep, as positive polarity CH HSS influences gradually diminish. Mostly quiet conditions are expected to prevail on 28 Sep.