G3 – Strong geomagnetic storm following multiple CME impacts

A G3 – Strong geomagnetic storming was observed on August 12, 2024, following multiple impacts from coronal mass ejections (CMEs) produced since August 7.

The solar wind environment was enhanced over the past 24 hours, due to persistent CME effects from the likely arrival of the CMEs produced on August 7, followed by the arrival of a CME associated with the X1.3 solar flare on August 8.

The total field reached 21 nT, Bz saw a maximum southward deflection to -15 nT, and wind speeds peaked at 539 km/s. Phi was in a mostly negative orientation through 13:20 UTC on August 11 UTC when it switched into a positive position through the remainder of the period, SWPC forecasters said at 00:30 UTC today.

Geomagnetic K-index of 5 (G1 – Minor geomagnetic storm) threshold was reached at 08:35 UTC on August 11 and continued at active to G1 levels through 00:56 UTC on August 12 when G2 – Moderate geomagnetic storming was observed.

G3 – Strong geomagnetic storm conditions (Geomagnetic K-index of 7) were observed at 05:28 UTC and again at 08:11 UTC today.

A G3 – Strong geomagnetic storm can primarily affect areas poleward of 50 degrees Geomagnetic Latitude. It may cause power system voltage irregularities and trigger false alarms in protection devices. Spacecraft might experience surface charging, increased drag, and orientation issues. GPS navigation could be intermittently disrupted, leading to signal loss and increased range errors. HF radio communications might also be affected.

As a result, red aurora was observed as far south as Nevada, U.S. With the Perseid meteor shower peaking at this time, some of the photographers made lucky shots showing both:

Solar wind parameters are expected to see further enhancements today as the two CMEs from August 8 and 10 are anticipated to pass at or near Earth. However, confidence in the expected magnitude of these CMEs is low.

Solar activity was at moderate levels over the past 36 hours, with several M-class flares and a couple of C-class. No new Earth-directed CMES were detected in available satellite data.

Solar activity is expected to be at moderate to high levels, with 75% of M-class and 30% of X-class solar flares through August 14.

There is a slight chance for S1 – Minor solar radiation storming through August 14. The greater than 2 MeV electron flux is expected to remain at normal to moderate levels.

References:

¹ Forecast Discussion – NOAA/SWPC – Issued at 00:30 UTC on August 12, 202

Featured image: Aurora over Government Camp, Oregon captured on August 11, 2024. Credit: Quinn, SpaceWeather