A full halo CME was first seen at 05:36 UT on LASCO C2, originating from an eruption close to NOAA AR 3683 (located at the southwest, at S25W60), associated with a C6.7 flare. The CME is fast, early speed estimates are around 1500 km/s, but more images are needed for a better estimation. The bulk of the CME is directed to the southwest, but a glancing blow can be expected on 22 May. Due to the location of the event and the speed of the CME, a proton event may occur in the coming hours.

A halo or partial-halo CME was detected with the following characteristics: t0 | dt0| pa | da | v | dv | minv| maxv| 2024-05-20T05:36:07.525 | 1.0 | 239 | 180 | 1564 | 235 | 1079 | 1956 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

There are nine visible ARs on the solar disk. Flaring activity was driven by NOAA AR 3685 (beta-gamma magnetic field configuration) with three M-class flares, the strongest being an M2.5 one peaking at 17:47 UTC on 21 May. NOAA AR 3683 (beta magnetic field configuration) has produced several C-class flares today and has potential for stronger ones. More M-class flares are likely and X-class flares are possible in the next 24 hours. A full halo CME was first seen at 05:36 UT on LASCO C2, originating from an eruption close to NOAA AR 3683 (located at the southwest, at S25W60), associated with a C6.7 flare. The CME speed is around 1500 km/s.The bulk of the CME is directed to the southwest, but a glancing blow can be expected on 22 May. The 10 MeV GOES-18 proton flux was below threshold in the past 24 hours. It may increase over the next hours as a result of the halo CME from 05:36 UTC. The greater than 2 MeV electron flux from GOES 16 was below the threshold level in the last 24 hours. It is expected to remain below the threshold during the next 24 hours. The electron fluence was at normal levels for the last 24 hours and is expected to remain so.

Geomagnetic conditions have been quiet in the last 24 hours (Kp and K_BEL up to 2). If we see a glancing blow from the 17 May CME, disturbed conditions may occur, otherwise quiet conditions can be expected for the next 24 hours. The solar wind at the Earth is slow, with speeds around 350 km/s and interplanetary magnetic field around 8 nT. There are low chances of a glancing blow from the CME on 17 May, otherwise slow wind conditions can be expected for the next 24 hours.