The greater than 10 MeV proton flux as measured by GOES 16 and GOES 18 has now exceeded the 10 pfu threshold marking a minor solar radiation storm. The proton flux levels were increased as a result of the solar activity on Sept 14th with X4.5 flaring from NOAA 3825 (beta-gamma) and associated halo coronal mass ejection (CME), which has now arrived to Earth. The greater than 10 MeV proton flux levels are expected to remain elevated on Sept 17th and start declining on Sept 18th in case of no new strong eruptive solar activity.

Solar flaring activity over the past 24 hours remained at low levels with background C-class flaring. There are seven numbered regions on the visible solar disc with NOAA AR 3825 (beta-gamma-delta) remaining the largest and most complex region. Most of the flaring activity was produced by NOAA AR 3824 (beta-gamma), which is now approaching the west limb, NOAA AR 3825 and NOAA AR 3829 (beta). The solar flaring activity is likely to be predominantly at low levels over the coming days with 50% chances of M-class flares and 15% chances for isolated X-class flaring. No Earth-directed coronal mass ejections (CMEs) have been detected in the available coronagraph imagery over the past 24 hours. Over the past 24 hours the greater than 10 MeV GOES proton flux has returned to nominal levels and is expected to remain so over the next 24 hours. The greater than 2 MeV electron flux as measured by GOES 16 and GOES 18 was below the 1000 pfu threshold over the past 24 hours and is expected to remain so over the next 24 hours. The 24h electron fluence was at nominal levels and is expected to remain so in the next 24 hours.

The geomagnetic conditions over the past 24 hours were predominantly quiet to active with an isolated minor geomagnetic storm registered by the global Kp index between 00:00 and 03:00 UTC on Sept 18th. Mostly quiet to active geomagnetic conditions with small chances for further isolated minor storms are expected over the next days. Over the past 24 hours the solar wind parameters (ACE and DSCOVR) were slightly perturbed. The interplanetary magnetic field reached 9.4 nT with Bz as low as - 8.8 nT. The solar wind velocity varied in the range of 375 km/s to 532 km/s. The B field phi angle remained predominantly in the positive sector (directed away from the Sun). The solar wind conditions are expected to continue to be slightly perturbed in the upcoming days under the possible influence of two mild high speed stream arrivals.