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Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2023 Feb 26 1252 UTC

SIDC Forecast

Brillamenti solari

M-class flares expected (probability >=50%)

Geomagnetism

Moderate (ISES: Major) magstorm expected (A>=50 or K=6)

Protoni solari

Proton event in progress (>10 MeV)

	10cm flux	Ap
26 Feb 2023	164	030
27 Feb 2023	164	087
28 Feb 2023	164	087

Bulletin

Solar flaring activity became high with a long duration M6.3 flare peaking at 19:44UTC from NOAA active region 3229, with associated radio bursts. Another M1 flare originated earlier from NOAA active region 3136. NOAA active region 3234 remained quiet but continues to be the most complex region on disc showing further growth and continued emergence of mixed flux in the intermediate area. NOAA active region 3229 seems to further shrink and reduce in complexity. First growth and then consolidation was observed in NOAA active region 3236. the other regions were stable or in decay. M-class flaring is expected with also a chance for an X flare, in particular from NOAA active region 3234.

SoHO/LASCO coronagraph images show an asymmetric halo CME towards the west- northwest appearing in the C2 field of view at 19:36UTC February 25. The projected speed is around 1000km/s. The event is associated to the M6.3 flare, and an on disc dimming in SDO 193 images and filament eruption SDO 304 images. Given the source location on disc and the halo extent in coronagraph images the CME is estimated to have an Earth directed component and model runs indicate an estimated arrival around 18:00UTC February 27.

The greater than 10 MeV proton flux became further enhanced after the M6.3 flare, crossing the 10pfu event threshold around 21:10UTC. The proton flux is expected to remain above the event threshold over the next day before starting to decay. The greater than 2 MeV electron flux was below the 1000 pfu threshold and is expected to remain below this threshold over the next days. The 24h electron fluence was at normal levels and is expected to be at normal levels over the next 24 hours.

An equatorial coronal hole of negative polarity that transited the central meridian earlier is expected to add to the solar wind perturbations starting late tomorrow February 27.

Solar wind speed increased gently reaching just over 500km/s by the end of the period. The interplanetary magnetic field was enhanced reaching a magnitude of 11nT. The northsouth component of the magnetic field was variable with an extended period of southward orientation in the afternoon of February 25 (Bz down to -8nT). The orientation of the magnetic field showed a switch from the positive (field away from the Sun) to the negative (field towards the Sun) sector around 7UTC this morning. Solar wind conditions are expected to become perturbed with subsequently the arrival late today of the February 24 CME then followed by a combination of the arrival of the February 25 CME and the high speed stream from the equatorial negative polarity coronal hole late tomorrow. Solar wind speed is expected to reach over 600 km/s.

Geomagnetic conditions were quiet to unsettled globally (NOAA Kp 2- to 3+) with active periods locally (K Belgium reaching 4) in the afternoon of February 25. Geomagnetic conditions are expected to reach minor to moderate storm levels (with a possibility of reaching major storm levels) later today and over the next days due to the expected CME and high speed stream solar wind perturbations.

Today's estimated international sunspot number (ISN): 142, based on 17 stations.

Solar indices for 25 Feb 2023

Wolf number Catania	///
10cm solar flux	152
AK Chambon La Forêt	022
AK Wingst	014
Estimated Ap	013
Estimated international sunspot number	141 - Based on 19 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive

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