A CME impact at about 19:30 triggered an aurora which (for those with clear skies) was visibly across most of the UK and Northern Europe. Sunspot 4341 erupted on 20250118 at 18:09 UTC), releasing an X1.9-class solar flare.
I missed the peak (not paying attention to social media) but my NW facing meteor camera did capture a wide angle view from 22:00 to 23:00. The move is in mono (sadly), but the brightness of the aurora was outstanding, visible at times through cloud. This is a high speed time lapse movie.
My UKRAA magnetometer also detected its arrival, the storm and the tail off back to some sort of normality.
AT the outset of a storm I can often detect (as in this case) a pre-impact usually about 90 minutes before the main impact. this is visible in the dip in Bx and By lines at about 17:35UT. It appears to me that the main impact affecting this part of the Northern Hemisphere was at 19:15, a little earlier than the official NOAA impact time. An 'off the scale in both directions' disturbance is a serious storm and I understand that the storm was classified as G4 (Severe), one down from a maximum G5 (Extreme) storm.
Bx is the E-W deflection of the Earths magnetic field, By is the N-S deflection.
The storm abated slightly on the 20th but was still classified as G3.
At 19:00 on the 21st January, the storm appears to be over.
Finally, my muon detector captured the increase in Solar Wind associated with the CME (which caused a decrease in the muon count), delayed by about 24 hours as the Solar Wind travels far more slowly than the CME. The graph below shows the muon count from midnight 20250119 to 20250122 with a 4 hour sample window. The dip is very noticeable.
Looking forward to the next one..