M9.1 solar flare erupts from geoeffective Region 3663

A very strong solar flare measuring M9.1 erupted from Active Region 3663 at 06:19 UTC on May 4, 2024. The event started at 06:02 and ended at 06:30 UTC. This is the 6^th and the strongest M-class solar flare since X1.6 on May 3.

This eruption was associated with type II (estimated velocity 950 km/s) and IV radio emissions, suggesting a coronal mass ejection (CME) was produced.

In addition, a 10 cm Radio Burst with a peak flux of 280 sfu was detected from 06:13 to O6:16 UTC. 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. The 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 Asia and the Indian Ocean at the time of the flare.

While coronagraph imagery is still unavailable, the location of Region 3663 suggests a part of the ejecta may be Earth-directed.

Such was the case with the X1.6 solar flare on May 3. While most of it appeared to be heading north, forecast models now suggest a part of it will impact Earth late May 5 into May 6. As a result, a G2 – Moderate geomagnetic storm watch is in effect.

The following images are from the X1.6 flare on May 3.

Featured image credit: NASA/SDO AIA 131, Helioviewer, The Watchers. Acquired at 06:19 UTC on May 4, 2024