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Daily bulletin on solar and geomagnetic activity from the SIDC

Vydáno: 2023 Feb 25 1244 UTC

SIDC Forecast

Sluneční erupce

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

Geomagnetism

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

Sluneční protony

Quiet

	10cm flux	Ap
25 Feb 2023	160	011
26 Feb 2023	160	039
27 Feb 2023	160	083

Bulletin

Solar flaring activity was moderate. Despite the decay observed in NOAA active region 3229 over the past days, it was the source of the strongest flare of the period: an M3.7 flare peaking at 20:30UTC, following new flux emergence ahead of the leading spot. Another M flare was observed from NOAA active region 3235, while NOAA active region 3234 only produced low C level flaring. NOAA active region 3236 showed growth with now mixed polarities in the vicinity of the leading spot. Also the leading spot of NOAA active region 3234 grew and the region maintains the mixed polarity spots in the trailing area. Flaring at M level is expected with also a potential for C class flaring.

The M3.7 flare came associated with radio bursts and filament eruption from the same location. A full halo CME was recorded associated to the event. The CME is first visible in the C2 field of view starting 20:36UTC. It is mainly directed towards the northwest but has a full halo extent. Given the location of the source and the halo extent it is expected that the CME has an Earth directed component. Modelling runs indicate an arrival around February 26. SoHO LASCO images earlier recorded a (partial) halo CME towards the northeast visible in the C2 field of view starting around 13:25UTC. This event is believed to be backsided and will not influence Earth. No other Earth directed CMEs have been observed in coronagraph data.

The greater than 10 MeV proton flux became slightly enhanced after the M3.7 flare, though remaining below the 10pfu event threshold and is expected to now follow a slowly decaying trend. 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 transited the central meridian and is expected to influence solar wind conditions starting late February 27.

Solar wind speed decreased from around 500 km/s to currently around 400km/s. The interplanetary magnetic field had a magnitude of around the nominal 5nT value with an orientation indicating connection to a positive sector (field away from the Sun) throughout the period. Slow solar wind conditions are expected to continue until tomorrow when we expect towards the end of the UTC day the arrival of yesterdays CME. Solar wind speed may reach up to 600km/s with the CME arrival. The passing CME effects will then later mix with the expected high speed stream that was expected for late on February 27.

Geomagnetic conditions were quiet (local K Belgium and NOAA Kp 1-2). Geomagnetic conditions will remain quiet to unsettled initially, rising to minor to moderate storm levels late tomorrow with the expected CME arrival.

Today's estimated international sunspot number (ISN): 140, based on 13 stations.

Solar indices for 24 Feb 2023

Wolf number Catania	///
10cm solar flux	164
AK Chambon La Forêt	007
AK Wingst	005
Estimated Ap	005
Estimated international sunspot number	124 - Based on 13 stations

Noticeable events summary

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

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