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Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2023 Feb 21 1257 UTC

SIDC Forecast

Brillamenti solari

C-class flares expected, (probability >=50%)

Geomagnetism

Active conditions expected (A>=20 or K=4)

Protoni solari

Quiet

	10cm flux	Ap
21 Feb 2023	161	022
22 Feb 2023	160	019
23 Feb 2023	159	025

Bulletin

Solar flaring activity reached moderate levels with 3 M flares all from Catania group 94 (NOAA active region 3234) which turned onto the disc in the northeast. The strongest was an M4.7 flare peaking at 11:23UTC. It produced a few further C flares as did Catania group 89 (NOAA active region 3229). Catania group 84 (NOAA active region 3226) continued to dissolve in the trailing end. Catania group 91 (NOAA active region 3231) showed further spreading and wekening over the period though with some renewed flux emergence towards the end of the period. The most complex region remains Catania group 89 (NOAA active region 3229) still containing opposite flux areas. Catania group 94 (NOAA active region 3234), is still a bit foreshortened but seems a regular, though active, bipolar region. Flaring at C level is expected with still a significant chance for an isolated M flare.

No new Earth directed CMEs have been observed in coronagraph data.

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours. There is a small chance of a proton event exceeding the 10pfu threshold, due to possible further high-level flares. 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.

A (negative polarity) extension of the southern polar coronal hole has been transiting the central meridian since yesterday. It may influence solar wind conditions at Earth from around noon February 23.

Solar wind conditions remained perturbed by the glancing impact of the September 17 CME. Solar wind speed touched briefly to almost 500 km/s early in the period but has decreased to under 400 km/s currently. The magnitude of the interplanetary magnetic field reached up to 15nT early and late in the period. During the morning the orientation of the magnetic field has also been pronounced southward with a Bz value reaching down to -12nT. Solar wind conditions are expected to remain perturbed but generally decreasing in the next 24 hours under the waning influence of the CME and the high speed stream influence associated to the equatorial positive polarity coronal hole. Afterwards a switch into the negative sector (field towards the Sun) is expected, potentially followed around noon February 23 by a high speed stream from the extension of the south pole coronal hole.

Geomagnetic conditions were mostly quiet to unsettled (local K Belgium 2-3) with only a single active period observed in NOAA Kp index. Geomagnetic conditions are expected to be quiet to unsettled with isolated active periods still possible.

Today's estimated international sunspot number (ISN): 114, based on 09 stations.

Solar indices for 20 Feb 2023

Wolf number Catania	141
10cm solar flux	160
AK Chambon La Forêt	020
AK Wingst	009
Estimated Ap	009
Estimated international sunspot number	127 - Based on 15 stations

Noticeable events summary

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

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