Solar Activity Alerts

:Product: Forecast Discussion :Issued: 2026 Sep 20 0030 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity reached low levels. The largest flare was a C3.3 flare at 19/1817 UTC from a source beyond the northeast limb. Early in the period B-flare activity was observed from an unnumbered region rotating into view on the southeast limb. New Region 4532 (S06W39, Axx/alpha) emerged with a rudimentary spot, but was otherwise unremarkable. No Earth-directed CMEs were detected in available coronagraph imagery. .Forecast... Solar activity is expected to be at very low levels on 20-22 Sep. Energetic Particle .24 hr Summary... 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 likely to reach high levels on 20-22 Sep. The greater than 10 MeV proton flux is expected to continue at background levels through 22 Sep. Solar Wind .24 hr Summary... The solar wind environment remained undisturbed over the past 24 hours. Total field strength ranged between 3-7 nT, and the Bz component varied between +/-5 nT. Solar wind speeds ranged between 400-450 km/s throughout the period. The phi angle was negative. .Forecast... Ambient solar wind conditions are expected to prevail over 20-22 Sep. Geospace .24 hr Summary... The geomagnetic field was at quiet to unsettled levels. .Forecast... Mostly quiet geomagnetic field conditions are expected to prevail over 20-22 Sep.

:Product: Forecast Discussion :Issued: 2026 Sep 19 1230 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity was very low and the solar disk was without spots. No Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity is expected to be at very low levels over 19-21 Sep. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels. 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 19-21 Sep. The greater than 10 MeV proton flux is expected to persist at background levels through 21 Sep. Solar Wind .24 hr Summary... Solar wind parameters persisted at background levels this period. Total magnetic field strength averaged near 6 nT, and the north-south (Bz) component ranged between +/- 5 nT. Solar wind speeds averaged ~430 km/s. The phi angle was predominantly negative. .Forecast... Ambient solar wind conditions are expected to prevail over 19-21 Sep. Geospace .24 hr Summary... The geomagnetic field was quiet with an isolated period of unsettled conditions. .Forecast... Mostly quiet conditions are expected to prevail over 19-21 Sep.

:Product: Forecast Discussion :Issued: 2026 Sep 19 0030 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity was very low and the solar disk was without spots. No Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity is expected to be at very low levels over 19-21 Sep. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels. 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 19-21 Sep. The greater than 10 MeV proton flux is expected to persist at background levels through 21 Sep. Solar Wind .24 hr Summary... Solar wind parameters returned to background levels this period following negative polarity CH HSS influences. Total field strength average near 5 nT, and the Bz component was predominately neutral or northward. Solar wind speeds gradually decreased from a peak of 500 km/s early in the period to a low of around 400 km/s. The phi angle was negative. .Forecast... Ambient solar wind conditions are expected to prevail over 19-21 Sep. Geospace .24 hr Summary... The geomagnetic field was quiet. .Forecast... Mostly quiet conditions are expected to prevail over 19-21 Sep.