Date: 2025 May 11 1230 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
Solar activity was low. Region 4079 (N08W88, Dkc/beta-gamma) produced C-class flare activity this period, the largest of which was an impulsive C5.5 flare at 10/1621 UTC. Minor development was observed in Region 4085 (N03E17, Cro/beta) and new Region 4086 (N07W49, Bxo/beta) was numbered. The remaining regions were either stable or in decay, and were quiet throughout the period. No Earth-directed CMEs were detected in available imagery.
Forecast: Solar activity is expected to be low over 11-13 May, with a chance for M-class (R1-R2/Minor-Moderate) flares on 11 May.Energetic Particle The greater than 2 MeV electron flux was at normal to moderate levels, and the greater than 10 MeV proton flux was at background levels.
Forecast: The greater than 2 MeV electron flux is expected to continue at normal to moderate levels over 11-13 May, and the greater than 10 MeV proton flux is expected to persist at background levels through 13 May.
The solar wind environment was mildly enhanced as negative polarity CH HSS influences began to wane. Total IMF strength reached 8 nT and the Bz component varied between +5/-7 nT. Solar wind speeds steadily declined from a peak of around 550 km/s to end-of-period values between 400-450 km/s. The phi angle was negative throughout the period.
Forecast: Mildly enhanced solar wind conditions are expected to prevail over 11-13 May as negative polarity CH HSS influences wane and subside (on 11 May), and positive polarity CH HSS influences commence (on 12-13 May).
Forecast: Periods of active conditions are expected on 11 May as negative polarity CH HSS influences wane and subside. Quiet to unsettled levels are expected over 12-13 May as a positive polarity CH HSS becomes geoeffective.