Viewing archive of Tuesday, 26 September 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Sep 26 1232 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
26 Sep 2023	170	011
27 Sep 2023	166	024
28 Sep 2023	162	013

Solar Active Regions and flaring

Solar flaring activity over the past 24 hours was at low levels. The largest flare was a C5.7-flare, with peak time 04:28 UTC on September 26, produced by NOAA AR 3445 (beta-gamma). There are currently 10 numbered active regions on the visible disk. NOAA AR 3445 (beta-delta) has been the most active region in the last 24 hours producing most of the C-class flares, NOAA AR 3443 (beta-gamma) has started to rotate off the visible disk and NOAA AR 3435 (beta-gamma-delta) has become more magnetically complex, all other regions have simple alpha or beta magnetic field configurations. A new region numbered NOAA AR 3448 has started to rotate onto the visible disk. The solar flaring activity is likely to remain at low levels over the coming days with C-class flares expected, M-class flares possible and a low chance for isolated X-class flaring.

Coronal mass ejections

No Earth directed CMEs have been observed in the last 24 hours. Two filament eruptions were observed. The first filament eruption was observed from 15:48 Sep 25 in SDO/AIA 304 data on the north- west quadrant. The second filament eruption was observed from 23:21 UTC Sep 25 in SDO/AIA 304 data on the north-east quadrant. Analysis is pending further coronagraph data.

Solar wind

In the last 24 hours, the Earth was under the influence of the ICME from 21 September. The interplanetary magnetic field gradually decreased from 30 nT to 06 nT and the Bz was negative from 03:10 UTC until 11:00 UTC Sep 26 down to – 12 nT. The solar wind speed fluctuated between 419 km/s to 509 km/s. The phi-angle has mainly been in the positive sector (directed away from the Sun). Solar wind conditions are expected to remain enhanced on September 26 gradually returning to slow solar wind conditions from September 27.

Geomagnetism

The geomagnetic conditions over the past 24 hours reached minor storm levels globally (Kp 5 -) and active conditions locally (K Bel 4). Active geomagnetic conditions to minor storm levels are expected in the next 24 hours.

Proton flux levels

The greater than 10 MeV proton flux was at background level over the last 24 hours and is expected to remain so in the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES-16 stayed below threshold value. The greater than 2 MeV electron flux is expected to remain below the threshold in the next 24 hours. The 24h electron fluence was at nominal levels and is expected to remain at nominal levels in the next 24 hours.

Today's estimated international sunspot number (ISN): 145, based on 20 stations.

Solar indices for 25 Sep 2023

Wolf number Catania	///
10cm solar flux	170
AK Chambon La Forêt	028
AK Wingst	024
Estimated Ap	024
Estimated international sunspot number	182 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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