A major disturbance is arriving at L1, starting around 11:30 UT. This is likely an early arrival of the ICME associated with the September 13 CME, which was originally expected later today. Solar wind speed has reached 815 km/s, reflecting the transient's elevated speed. No shock is currently visible in the data, as the magnetic field strength has not yet increased. Geomagnetic conditions are expected to rise significantly in the coming hours, though Bz currently remains positive. Further updates will be provided as more data becomes available.

A halo or partial-halo CME was detected with the following characteristics: t0 | dt0| pa | da | v | dv | minv| maxv| 2026-09-12T22:00:33.567 | 6.0 | 13 | 256 | 1525 | 340 | 502 | 1953 t0: onset time, earliest indication of liftoff dt0: duration of liftoff (hours) pa: principal angle, counterclockwise from North (degrees) da: angular width of the CME (degrees), v: median velocity (km/s) dv: variation (1 sigma) of velocity over the width of the CME mindv: lowest velocity detected within the CME maxdv: highest velocity detected within the CME

A total of 4 numbered sunspot groups were identified on the disk over the past 24 hours. Solar activity has been very low in the last 24 hours, with no C-class flares observed. Solar flaring activity is expected to be low over the next 24 hours, with C-class flares likely. No Earth-directed CMEs were detected in the last 24 hours. SIDC Coronal Hole 142 is at mid to high latitude in the northern hemisphere, it crossed central meridian on September 13. The greater than 10 MeV proton flux remained below the 10 pfu threshold. The greater than 2 MeV electron flux, as measured by GOES-18 and GOES-19, remained mostly below the 1000 pfu alert threshold over the past 24 hours. The greater than 2 MeV electron flux may exceed the alert threshold over the next 24 hours.The 24-hour electron fluence was at moderate levels and is expected to remain at moderate levels over the next 24 hours.

Geomagnetic conditions have reached active levels both locally and at planetary levels (Kp and K_Bel up to 4) in the last 24 hours. The combination of ongoing ICME effects and high speed stream arrival will likely elevate geomagnetic conditions in the coming hours. Minor to major storm conditions can be expected. The solar wind at the L1 point was under the influence of an ICME that started on 14 September. The interplanetary magnetic field had reached 16 nT, without a marked negative Bz. At present, a major disturbance is arriving at L1, starting around 11:30 UT on 15 September. This is likely an early arrival of the ICME associated with the September 13 CME, which was originally expected later today. Solar wind speed has reached 815 km/s, reflecting the transient's elevated speed. No shock is currently visible in the data, as the magnetic field strength has not yet increased. Bz currently remains positive. Further updates will be provided as more data becomes available. Furthermore, in about 24 hours a high speed stream from SIDC Coronal Hole 142 is expected to arrive.