Viewing archive of Tuesday, 20 September 2022

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2022 Sep 20 1232 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

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

	10cm flux	Ap
20 Sep 2022	130	010
21 Sep 2022	130	007
22 Sep 2022	130	012

Bulletin

An M1 flare was released from Catania group 35 (NOAA active region 3102) peaking at 11:22UTC. In addition, a number of C-class flares have been recorded, most of them from Catania group 35 (NOAA active region 3102), but also from the new region that rotated onto the disc in the South-East. Catania group 35 (NOAA active region 3102) lost some of its intermediate spots but remains the most significant region on disc. The new region that rotated onto the disc in the South-East is now numbered NOAA active region 3105, but is counted as two separate sunspot groups 42 and 43 by Catania. Both included sunspot groups are bipolar. Catania group 41 (NOAA region 3104) showed spreading of the footpoints and seems to be already in decay. Further flaring at C level is expected with also 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 slightly enhanced but well below minor storm warning threshold. The greater than 10 MeV proton flux is expected to remain 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 well below the 1000 pfu threshold and is expected to remain so over the next 24 hours. The 24h electron fluence was at nominal 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. We are expecting to see its associated high speed stream in in situ Solar wind conditions from around noon September 22.

Solar wind conditions continued to show the influence of a high speed stream, with the solar wind speed reaching over 500km/s again. Although it has by now again decreased to below 500 km/s. The magnitude of the interplanetary field decreased to now around a nominal 5nT. The north-south component was variable and the field orientation showed connection to a negative sector (magnetic field towards the Sun). A further decay towards slow Solar wind conditions is now expected and we are no longer anticipating any late arrival of the possible glancing blow by the September 16 CME. Later in the week on September 22 to 23 we are expecting a renewed increase to high speed Solar wind conditions, related to the coronal hole that has just transited the central meridian.

Geomagnetic conditions were mostly quiet to unsettled (NOAA Kp 1-3) with locally some active periods (K Dourbes reaching 4). Geomagnetic conditions are expected to be quiet to unsettled with a remaining slight chance for isolated active periods. By late September 22 chances for active periods or minor storm levels are increasing due to the anticipated onset of high speed Solar wind conditions.

Today's estimated international sunspot number (ISN): 065, based on 21 stations.

Solar indices for 19 Sep 2022

Wolf number Catania	074
10cm solar flux	128
AK Chambon La Forêt	020
AK Wingst	014
Estimated Ap	013
Estimated international sunspot number	068 - Based on 30 stations

Noticeable events summary

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

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