Viewing archive of Thursday, 22 September 2022

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2022 Sep 22 1239 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
22 Sep 2022	139	014
23 Sep 2022	139	031
24 Sep 2022	139	013

Bulletin

A number of C flares occurred of which the strongest peaked at 23:20UTC from NOAA active region 3105 (Catania group 42). Further C flares originated from NOAA active region 3107 and a new bipolar region that emerged near the centre of the disc, NOAA active region 3109. NOAA region 3102 (Catania sunspot group 35) lost more of its spots in the intermediate region and was overall stable and inactive. NOAA active region 3107 that turned onto the disc yesterday is a bipolar region with a dominant leading spot. Another small bipolar region (NOAA active region 3108) emerged on disc. Meanwhile NOAA active region 3106 decayed into plage. Further flaring at C level is expected with still a chance for M-class flaring.

No Earth-directed coronal mass ejections (CMEs) were detected in the available coronagraph imagery over the past 24 hours.

In the past 24 hours the greater than 10 MeV proton flux remained just slightly enhanced but well below 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. We are expecting to see its associated high speed stream in in situ Solar wind conditions later today or tomorrow. An low latitude extension of the southern polar coronal hole is about to transit the central meridian and may influence solar wind starting from around noon September 26. Solar wind showed a decrease to slow solar wind conditions. Solar wind speed decreased to around 400 km/s and the magnitude of the interplanetary magnetic field was at or below 5nT. The orientation of the magnetic field mostly showed a connection to a negative sector (field towards the Sun). We are expecting today a switch into the positive sector (field away from the Sun) and may be currently seeing already some signs of that. Later today or tomorrow solar wind speed is expected to rise again with the onset of the high speed stream associated to the positive polarity coronal hole that transited the central meridian on September 19.

Geomagnetic conditions were quiet to unsettled (NOAA Kp 1-2 and local K Dourbes 1-3). Geomagnetic conditions are expected to evolve into quiet to active with a possibility for minor geomagnetic storm episodes in association to the expected high speed stream solar wind conditions.

Today's estimated international sunspot number (ISN): 105, based on 18 stations.

Solar indices for 21 Sep 2022

Wolf number Catania	///
10cm solar flux	137
AK Chambon La Forêt	006
AK Wingst	006
Estimated Ap	005
Estimated international sunspot number	082 - Based on 31 stations

Noticeable events summary

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

All times in UTC

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