Date: 2026 May 22 1230 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
Solar activity reached moderate levels. An M2.3 (R1-Minor) flare was observed at 22/1029 UTC from near Region 4436 (N18, L=334) around the NW limb. Several areas of developing pores were observed. An active region number will be assigned if the areas produce spots that persist. Region 4441 (N08W58, Eai/beta-gamma) was the largest and most complex; it continued to develop intermediate spots over the past 24 hours. Only minor changes were observed among the remaining active regions. No Earth-directed CMEs were observed in available coronagraph imagery.
Forecast: Solar activity is expected to remain at low levels with a chance for isolated M-class flares (R1-R2/Minor-Moderate) on 22-24 May, primarily due to the complexity of Region 4441 and the recent flaring history of Region 4436. Additionally, as multiple active regions (tracked via far-side satellite and helioseismology imagery) rotate into view, an increase in activity could occur over 23-24 May.Energetic Particle The greater than 2 MeV electron flux at geosynchronous orbit remained at high levels, reaching a peak level of 2841 pfu at 21/1550 UTC. The greater than 10 MeV proton flux at geosynchronous orbit remained at background levels.
Forecast: The greater than 2 MeV electron flux is expected to remain at moderate to high levels on 22-24 May as a weak coronal hole high-speed stream is likely to become geoeffective. The greater than 10 MeV proton flux is expected to remain at background levels through 24 May.
Solar wind parameters reflected near-background conditions. Wind speeds gradually decreased from 450 km/s to 350 km/s during the reporting period. Total magnetic field strength averaged ~4 nT. The phi angle was predominantly in a negative orientation.
Forecast: Solar wind parameters are expected to observe weak enhancements on 22-23 May as a positive polarity coronal hole high-speed stream (+CH HSS) is likely to become geoeffective. Conditions are likely to wane by 24 May as the CH HSS moves past Earth.
Forecast: Periods of unsettled conditions are likely over 22-23 May, with a chance for isolated active periods, following an anticipated sector boundary crossing and the onset of the approaching +CH HSS. Mostly quiet levels are anticipated on 24 May due to persistent, yet waning, +CH HSS influences.