This CME originated from the southwestern quadrant of the Sun and followed a shock signature observed at 15:47 UTC on March 21.
The post-event analysis confirmed the CME has an Earth-directed component, with expected arrival by early March 23.
As a result, geomagnetic storming is anticipated to intensify, with G3 – Strong levels possible on March 23. The SWPC forecasts continued active to unsettled conditions on March 24 as coronal hole high-speed stream (CH HSS) influences begin to subside.
Under G3 – Strong geomagnetic storm conditions, power systems may experience voltage irregularities, and protective devices could trigger false alarms due to induced currents. In space, satellites in low Earth orbit may face increased atmospheric drag and surface charging, which could affect their orientation and operational stability.
Navigation systems such as GPS may experience intermittent disruptions, including loss of signal lock and increased range errors. High-frequency (HF) radio communications may also be affected, becoming unreliable or intermittent. Additionally, auroras could be visible at much lower latitudes than usual, with possible sightings as far south as Pennsylvania, Iowa, and Oregon in the United States.
A G1 – Minor geomagnetic storm had already been recorded on March 21 following the impact of an earlier CME, likely linked to solar activity on March 17. The solar wind carried a peak total magnetic field strength of 40 nT, with a southward Bz component reaching -22 nT.
G2 – Moderate geomagnetic storm threshold was reached at 02:59 UTC on March 22 before subsiding to G1 – Minor again at 03:35 UTC.
Solar wind speeds ranged from 375–581 km/s before dropping to around 450 km/s by 08:00 UTC.
A diffuse aurora was confirmed in Nevada, with digital cameras capturing the phenomenon more effectively than the naked eye, as reported by Dr. Tamitha Skov on March 22.
Multiple active regions remain on the Sun’s visible disk, including newly numbered Regions 4036 through 4039. Region 4031 showed increased development but did not produce significant flaring.
Forecasts for March 22–24 include the potential for further isolated M-class flares.
Electron and proton flux levels remain below thresholds for significant radiation storms. The >10 MeV proton flux peaked at 1 pfu on March 21 but did not exceed S1 – Minor levels.
References:
1 Forecast Discussion – SWPC – Issued at 00:30 UTC on March 22, 2025