A Type II Radio Emission with an estimated velocity of 988 km/s was registered at 02:43 UTC, indicating a coronal mass ejection (CME) was associated with the event.
Active Region 4299 is located on the Sun’s northeastern limb, limiting the possibility for Earth-directed CMEs. However, this will change as the week progresses, and the region moves toward a geoeffective position.
This is the old Region 4274, source of multiple X-class flares during its last rotation over the Earth-side in early November, including X5.1 on November 11, which produced the strongest Ground Level Enhancement event in 20 years.
Other notable flares from this region include X4.0 on November 14, X1.7 on November 9, and X1.2 on November 10.
Radio frequencies were forecast to be most degraded over Australia at the time of the flare event.
“This storm is not Earth-directed (it is directed towards Saturn), but I would not be surprised if we see a radiation storm rise at Earth over the next few hours,” Space Weather Physicist Dr. Tamitha Skov said.
“Preliminary analysis of the recent X1.95-flare shows radio bursts of over 1.2 GHz observed at the new Wairakei SIGN station in New Zealand,” Skov said.
“This means this region has the potential to temporarily disrupt GPS/GNSS, satellite phone, and ADS-B airline transponder communications when it flares! Stay vigilant if you use these services while on the dayside of Earth!”
Solar activity decreased to low levels over the 24 hours to 00:30 UTC on December 1, with the strongest flare, C9.0, occurring at 10:54 UTC also from AR 4299. Region 4294 (beta-gamma-delta) persisted as the most complex region on the Sun, producing most of the C-class flare activity during the period. Newly numbered Region 4296 (beta) was also large in area but not as magnetically complex.
The forecast calls for a 70% chance of M-class flaring through December 3 and a 20% chance of X-class flaring. The same period brings a 10% chance of S1+ solar radiation storms, primarily driven by the eruption potential of Region 4294.
Solar wind parameters over the past 36 hours reflected the waning influence of a positive polarity coronal hole high speed stream (CH HSS), with total magnetic field strength between 5 and 6 nT. The Bz was primarily oriented southward, and the phi angle was predominantly positive.
Solar winds declined from around 625 km/s to near 525 km/s by 00:30 UTC today.
Positive polarity CH HSS influences are expected to wane today, followed by a return to at or near ambient levels over December 2. Another enhancement in solar wind parameters from a negative polarity CH HSS is expected on December 3.
The geomagnetic field was at quiet to active levels over the past 36 hours, under the influence of a waning positive polarity CH HSS.
Unsettled geomagnetic field levels, with a chance for active levels, are expected on December 1 as positive CH HSS influences wane. Mostly quiet conditions are expected to prevail on December 2 with the return of an ambient solar wind environment. Active conditions, with a chance for G1 – Minor, are likely with the anticipated onset of influence from a large, negative polarity coronal hole on December 3.
References:
1 Forecast Discussion – NOAA/SWPC – 00:30 UTC on December 1, 2025