A coronal mass ejection (CME) produced on December 13, 2024, impacted Earth at 05:19 UTC on December 17, sparking G1 – Minor geomagnetic storming. The K-index reached 5 at 08:07 UTC, with effects limited to areas poleward of 60 degrees geomagnetic latitude. Enhanced solar wind conditions, driven by a positive polarity coronal hole high-speed stream (CH HSS), are expected to continue through December 18. Meanwhile, solar activity remains low, with a 30-40% chance of M-class flares and a 5% chance of X-class flares through December 19.
A coronal mass ejection (CME) produced on December 13, impacted Earth at 05:19 UTC on December 17, sparking G1 – Minor geomagnetic storming. Conditions are conducive for at least G2 – Moderate storming while some forecasters expect even G3 – Strong geomagnetic storming today.
Geomagnetic K-index of 5 (G1 – Minor geomagnetic storm) threshold was reached at 08:07 UTC. Area of impact is primarily poleward of 60 degrees Geomagnetic Latitude. This is the lowest level geomagnetic storm on the NOAA scale. Potential impacts include weak power grid fluctuations, minor impact on satellite operations and aurora at high latitudes.
The solar wind environment was already enhanced due to positive polarity coronal hole high speed stream (CH HSS) influence.
Enhanced solar wind conditions are expected to prevail over December 17 due to continued weak positive polarity CH HSS influence and possible glancing influences of CME(s) produced from December 13 to 15 which are expected to pass in close proximity today and tomorrow.
Solar activity was at low levels over the past 24 hours until a large filament eruption at 07:00 UTC today. The CME it produced appears to be heading away from Earth.
There are currently five numbered sunspot regions on the Earth-facing side of the Sun. NOAA forecasters estimate a 40% chance of M-class solar flares today, decreasing to 30% on December 18 and 19, with a 5% chance of X-class flares on all three days.