Date: 2026 Sep 12 1230 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
Solar activity was very low. Regions 4521 (N09W87, Hsx/alpha) and 4524 (N12W37, Hsx/alpha) produced a few B-level enhancements as they moved closer to the western limb. All seven of the numbered regions were either stable or reflected slight decay. No Earth-directed CMEs were observed in available coronagraph imagery.
Forecast: Solar activity is expected to remain at very low levels, with C-class flares likely and a slight chance of isolated low-level M-class flares (R1-Minor) through 14 Sep.Energetic Particle The greater than 2 MeV electron flux reached high levels with a maximum flux of 7,008 pfu observed at 11/1355 UTC. The greater than 10 MeV proton flux was at background levels.
Forecast: The greater than 2 MeV electron flux is expected to reach high levels on 12 Sep and decline to low to moderate on 13-14 Sep. The greater than 10 MeV proton flux is expected to remain at background levels.
Solar wind conditions remained near-background levels. Total field strength varied between 1-7 nT, the Bz component fluctuated between +/- 6 nT, and solar wind speed averaged close to 425 km/s through the period. The phi angle oscillated between sectors until just after the turn of the UTC day when it remained in a mostly positive orientation.
Forecast: Solar wind conditions could experience minor disturbances on 12 Sep, due mainly to a small, positive polarity CH HSS that is expected to remain geo-effective through the day. Negative CH HSS effects are anticipated to begin late on 13 Sep and last through 14 Sep.
Forecast: The geomagnetic field is expected to be quiet to unsettled, with isolated active periods possible, on 12-13 Sep as +CH HSS influence is expected to continue. Late on 13 Sep, an anticipated SSBC ahead of a negative polarity coronal hole high speed stream is anticipated to begin influencing the IMF, bringing unsettled to active levels on 14 Sep.