Viewing archive of Wednesday, 21 September 2022

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2022 Sep 21 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
21 Sep 2022	135	006
22 Sep 2022	135	014
23 Sep 2022	135	031

Bulletin

An impulsive M flare occurred this morning. Now from a new region (NOAA active region 3107) that has just turned onto the visible disc in the South-East. The flare peaked at M1.0 level at 9:04UTC. NOAA active region 3107 is located south-east of NOAA active region 3105 and still close to the limb. In correspondence with the observations by Catania, the Catania sunspot group 43 was now numbered NOAA active region 3106 to separate it from Catania sunspot group 42 (NOAA active region 3105). The trailing spot of Catania sunspot group 43 (NOAA active region 3106) seems to have largely decayed though by now. Catania group 35 (NOAA active region 3102) showed consolidation in the trailing area but remains the most significant region on disc. While new NOAA active region 3107 must be analysed more closely as it now turns better into view. Further flaring at C level is expected with a significant chance for further M-class flaring, both from NOAA 3102 and from the regions in the East.

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. Subject to strong activity from Catania group 35 proton levels may rise again, though there is just a small probability for this at present. 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, though with a slightly increasing trend.

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 from around noon tomorrow.

Solar wind conditions continued to be in a state between slow and fast solar wind. Solar wind speed hovered around 500km/s and the magnetic field magnitude was around a nominal 5nT, with a variable Bz component. The magnetic field orientation showed connection to a negative sector (magnetic field towards the Sun). Late today or tomorrow a switch into a positive sector (magnetic field away from the Sun) must be anticipated, then followed tomorrow by an expected increase towards fast Solar wind conditions associated with the high speed stream from the equatorial coronal hole that crossed central meridian September 19.

Geomagnetic conditions were quiet to unsettled (NOAA Kp and local K Dourbes 1-3). Geomagnetic conditions are expected to initially (next 24 hours) remain quiet to unsettled with isolated active periods possible, and then to evolve into active conditions becoming more probable with a possibility for minor geomagnetic storm episodes.

Today's estimated international sunspot number (ISN): 084, based on 18 stations.

Solar indices for 20 Sep 2022

Wolf number Catania	084
10cm solar flux	137
AK Chambon La Forêt	014
AK Wingst	010
Estimated Ap	010
Estimated international sunspot number	065 - Based on 29 stations

Noticeable events summary

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

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