Viewing archive of Tuesday, 27 September 2022

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2022 Sep 27 1247 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
27 Sep 2022	138	024
28 Sep 2022	140	031
29 Sep 2022	142	010

Bulletin

Solar flaring activity was at low levels. Most of the C-class flares were associated with Catania group 47 (NOAA AR 3107), including the largest flare that was a C4.8 flare, peaking on September 27 at 06:46 UT. Other low level C-class flares were produced by Catania group 42 (NOAA AR 3105). Catania group 47 (NOAA AR 3107) and Catania group 48 (NOAA AR 3110) are the most complex regions on disk. A new active region, Catania group 50, has also begun to rotate onto the solar disk over the north-east limb. Solar flaring activity is expected to be at low levels, with C-class flares likely and M-class flares remain possible, particularly from Catania group 47.

No new Earth directed Coronal Mass Ejections (CMEs) were detected in the available coronagraph imagery.

In the past 24 hours the greater than 10 MeV proton flux increased slightly but remained well below the minor storm warning threshold. The greater than 10 MeV proton flux is expected to remain below the radiation storm threshold over the next 24 hours. The greater than 2 MeV electron flux was above the 1000 pfu threshold on September 26 but decreased sharply during the geomagnetic storm. The 24h electron fluence was at normal to moderate levels over the past 24 hours. The 24h electron fluence is expected to decrease to normal levels in the next 24 hours.

The solar wind parameters showed a arrival of a CIR combined with a possible CME or transient feature. The solar wind speed was at 300 km/s at the beginning of the period and began to increase gradually from 19 UT to values near 550 km/s by 11 UT September 27. The interplanetary magnetic field increased and reached over 30 nT at 04:30 UT, with a minimum Bz of -17nT. The magnetic field orientation was mostly in the negative sector (field directed towards the Sun). The solar wind parameters are expected to continue to be enhanced over the next days, due to the influence of the high speed stream and further possible CME glancing blows predicted for September 27.

Geomagnetic conditions were quiet for the first half of the period. There was then an isolated period of moderate storm levels (NOAA Kp = 6 between 00:00 UT and 03:00 UT) in reaction to the strong negative magnetic field, before reducing again to active and unsettled conditions from 03 UT (NOAA Kp 2-4, local K-dourbes 3-4). Active periods are likely over the next days with minor storm intervals possible as the enhanced solar wind conditions continue to influence the Earth.

Today's estimated international sunspot number (ISN): 106, based on 13 stations.

Solar indices for 26 Sep 2022

Wolf number Catania	///
10cm solar flux	135
AK Chambon La Forêt	028
AK Wingst	007
Estimated Ap	006
Estimated international sunspot number	125 - Based on 20 stations

Noticeable events summary

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

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