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Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2022 Sep 24 1232 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
24 Sep 2022	146	017
25 Sep 2022	145	021
26 Sep 2022	144	026

Bulletin

The new Catania region 48 (NOAA active region 3110) in the North- East produced an M1.7 flare peaking at 18:10UTC, with associated radio bursts and CME. Several more C flares originated from Catania groups 47 and 45 (NOAA active regions 3107 and 3109). Both Catania groups 47 and 48 (NOAA active region 3107 and 3110) showed clear growth, with especially in Catania 47 (NOAA active region 3107) mixed polarity field and new flux emergence in the intermediate area. Flaring at C level is expected with also a significant chance for another isolated M flare.

The North-West directed CME of early September 22 reported yesterday has been analyzed and is not believed to have an Earth-directed component. The eruption around noon yesterday of a filament stretching from Catania group 35 (NOAA active region 3102) towards the West was associated with a partial halo CME as visible in SoHO/LASCO and STEREO-A coronagraph data. It is first visible in SoHO/LASCO C2 data at 13:48UTC and propagates mainly towards the West with an angular extension reaching around 180 degrees. The projected speed is measured as just over 500 km/s and estimates of the speed along the line of propagation are up to 600km/s. Given the location and direction a glancing blow from this CME cannot be excluded and if so, would preliminarily be expected in the morning of September 27. A more detailed model run is being prepared and analyzed. Associated to the M1.7 flare a CME was launched towards the East from near the East limb. It has an angular extent of around 160 degrees. This CME is assessed as being too far to the East off the Sun Earth line to influence Earth.

In the past 24 hours the greater than 10 MeV proton flux remained just very slightly enhanced but well below the minor storm warning threshold. The greater than 10 MeV proton flux is expected to remain slightly enhanced, but below the radiation storm thresholds over the next 24 hours. The greater than 2 MeV electron flux was below the 1000 pfu threshold and is expected to remain so over the next 24 hours. The 24h electron fluence was at normal levels over the past 24 hours and is expected to remain so in the next 24 hours.

An equatorial coronal hole of positive polarity has crossed the central meridian September 19 of which we are still expecting to see its associated high speed stream in in situ Solar wind conditions. A low latitude extension of the southern polar coronal hole is transiting the central meridian and may influence solar wind starting from around noon September 26.

Solar wind parameters reflect near to slow solar wind conditions. Solar wind speed varied between 400-500 km/s with currently around 450 km/s. The interplanetary magnetic field had a magnitude of between 4-8nT. There is no clear sign yet of the expected fast solar wind associated to the equatorial coronal hole that passed central meridian on September 19. We are still expecting to see an increase in solar wind speed, though since it seems to arrive late it is now also expected to be less pronounced. Around noon September 26 we may then start seeing the influence of the high speed stream from the extension of the southern polar coronal hole, then followed by a possible glancing blow early September 27 from the September 23 CME.

Geomagnetic conditions were quiet to active (NOAA Kp 2-4 and local K Dourbes 1-4). Geomagnetic conditions are expected to be quiet to active with still a possibility of minor storm levels being reached.

Today's estimated international sunspot number (ISN): 133, based on 12 stations.

Solar indices for 23 Sep 2022

Wolf number Catania	139
10cm solar flux	146
AK Chambon La Forêt	020
AK Wingst	012
Estimated Ap	012
Estimated international sunspot number	117 - Based on 22 stations

Noticeable events summary

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

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