Multiple Earth-directed CMEs, significant geomagnetic storming possible

Solar activity was at very high levels over the past 24 hours, with a series of moderate to strong solar flares, including an M9.9 flare on July 28 with an Earth-directed component. This, coupled with the cannibal CME expected to arrive late on July 29 into July 30, suggests significant geomagnetic storming is possible, potentially in the range of G3 – Strong or even G4 – Severe on July 30.

According to the SWPC update at 00:30 UTC on July 28, at least two Earth-directed coronal mass ejections (CMEs) have been observed since late July 26. The first CME was associated with a filament eruption late on July 26, first visible in LASCO C2 imagery at 21:24 UTC.

The second CME was produced by a long-duration M3.1 flare from Active Region 3762 that peaked at 05:46 UTC on July 27. The latter CME was the faster of the two in modeling results and is expected to cannibalize the former. Although the timing has low confidence, modeling results showed a first arrival late on July 29 to early July 30.

Based on this, SWPC predicted a G1 – Minor storm is likely late on July 29, increasing to G2 – Moderate as the bulk of the July 27 CME passes through the near-Earth environment.

However, solar activity further increased and reached very high levels with M9.9 at 01:57 UTC on July 28 from Active Region 3766. This event started at 01:53 and ended at 02:01 UTC.

Associated with this flare event was a Type II Radio Emission (estimated velocity 943 km/s) — suggesting a CME was produced, and a 10cm Radio Burst, lasting 6 minutes and with a peak flux of 250 sfu.

A 10cm radio burst indicates that the electromagnetic burst associated with a solar flare at the 10cm wavelength was double or greater than the initial 10cm radio background. This can be indicative of significant radio noise in association with a solar flare. This noise is generally short-lived but can cause interference for sensitive receivers including radar, GPS, and satellite communications.

Radio frequencies were forecast to be most degraded over East Asia and the Pacific Ocean at the time of this flare.

The location of the source region and available coronagraph imagery suggest we have another Earth-directed CME.

We are still waiting for updated models, but space weather physicist Dr. Tamitha Skov suggests we could be seeing at least G3 – Strong if not G4 – Severe storming as a result.

“With at least three if not four Earth-directed solar storms launched earlier today, this is sure to be the icing on the cake. It may not be as intense as the Gannon Storm back on May 10, but this compression of multiple back-to-back storms has at least G3 if not G4-level potential. Waiting for coronagraphs & model prediction runs,” Skov said.

The analysis of the M9.9 flare event is still in progress. This report will be updated accordingly.

References:

¹ Forecast Discussion – NOAA/SWPC – Issued at 00:30 UTC on July 28, 2024

Featured image credit: ESA/NASA SOHO, NASA SDO/AIA, Helioviewer, The Watchers