A strong solar flare measuring M9.0 erupted at 23:07 UTC on February 10, 2024, from geoeffective Active Region 3576. The event started at 22:56 and ended at 23:14 UTC. An Earth-directed CME is likely.

The event was associated with a Type II Radio Emission with an estimated velocity of 2 170 km/s. Type II emissions occur in association with eruptions on the Sun and typically indicate a coronal mass ejection (CME) is associated with a flare event. A Type IV Radio Emission was detected at 23:05 UTC. Type IV emissions occur in association with major eruptions on the sun and are typically associated with strong coronal mass ejections and solar radiation storms.

A 10cm Radio Burst (Tenflare) lasting 5 minutes and with a peak flux of 360 sfu was also associated with the flare event. 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.

Region 3576 is located in the center of the disk and has a ‘beta-gamma-delta’ magnetic configuration — capable of producing more strong to major eruptions.

Its location suggests any CME produced by it today and over the next couple days would likely be Earth-directed.

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

The flare comes one day after the old region (located beyond the SW limb) produced an X3.3 solar flare. Associated with this event was a 1 000 sfu Tenflare, a Type IV radio sweep and a partial-halo CME off the SW limb beginning at 13:25 UTC on February 9. The CME is not expected to have any Earth-directed component given its position beyond the SW limb.

Major X3.3 solar flare erupts behind the SW limb, S2 – Moderate solar radiation storm

Other notable events over the past 36 hours include a long-duration M3.4 flare observed from a region beyond the ESE limb at 03:54 UTC today. A partial-halo CME was observed off the SE limb beginning at 03:36 UTC. The CME is not expected to have any Earth-directed component given its position beyond the SE limb.

Region 3576 (S16W02, Fkc/beta-gamma-delta) produced two M-class flares; an M1.2 at 18:00 UTC yesterday and an M1.5/Sf at 00:51 UTC today.

A filament eruption centered near S37W02 beginning at 20:00 on February 8 was reanalyzed. A likely associated CME was observed off the S limb at 01:54 UTC in SOHO/LASCO C3 imagery. Modeling results indicated the potential for a grazing blow mid to late on February 12.

The greater than 10 MeV proton flux began to increase at 14:00 UTC on February 9 following the X3.3 flare. S1 – Minor levels were reached at 15:30 UTC and S2 – Moderate at 18:15 UTC.

Update

13:22 UTC, February 11

Initial coronagraph imagery associated with the M9.0 flare indicates a potential Earth hit early on 13 February.

At about 01:19 UTC today, an interplanetary shock was observed on the real-time solar wind plot. Wind speeds increased from about 350 km/s to about 435 km/s, eventually reaching about 500 km/s by about 03:13 UTC. The total field increased from 4 nT to 20 Nt, while the Bz component indicated a mostly negative trend to a low of -15 nT.

The shock arrived at Earth with a 40 nT deviation observed at the KBOU magnetometer at 02:11 UTC. This shock arrival was possibly associated with the suspected transient activity from the CMEs on February 8 and 9.

A combination of the February 8 CME and the late February 10 CME is expected to cause influences beginning mid to late on February 12 and continuing through the 13 ^th , resulting in unsettled to G1 -Minor storming, with possible G2 – Moderate intervals on February 13.

References:

¹ Forecast Discussion – Issued: 2024 Feb 10 1230 UTC – Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center

Featured image credit: NASA SDO/AIA 304, Helioviewer, The Watchers

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