Viewing archive of Friday, 21 April 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Apr 21 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
21 Apr 2023	150	011
22 Apr 2023	150	011
23 Apr 2023	150	005

Bulletin

Solar flaring activity was at low levels in the past 24 hours. There are seven active regions on the visible solar disc with NOAA AR 3282 (beta-gamma) being the largest and most complex one, which has produced only occasional low levels of flaring activity. The strongest activity was a C3.3 flare with peak time 16:23 UTC on April 20th produced by Catania sunspot group 65, which has now rotated on the disc from the east limb. Isolated low C-class flaring was produced by NOAA AR 3272 from behind the west limb and by NOAA AR 3281 (beta). The solar flaring activity is expected to continue at low levels over the next 24 hours with low chances for isolated M-class flaring.

No other Earth-directed coronal mass ejections (CMEs) have been detected in the available coronagraph imagery.

Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to remain so in the next 24 hours. The greater than 2 MeV electron flux has been below the1000 pfu threshold and is expected to remain so. The 24h electron fluence was at nominal levels and is expected to remain so over the next 24 hours.

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) have recovered from the previously ongoing ICME arrival. The solar wind velocity smoothly varied around 400 km/s. The interplanetary magnetic field had a maximum value of 9.09 nT with a weak minimum Bz of -5.3 nT. The B field was predominantly in the negative sector (directed towards the Sun) and has switched orientation over the past hours. Mildly elevated solar wind conditions are might be expected on April 21st and April 22nd under the influence of an anticipated high speed stream from a negative polarity coronal hole.

The geomagnetic conditions over the past 24 hours were quiet to unsettled. Mostly quiet to unsettled geomagnetic conditions are expected over the next 24 hours with possible active periods and small chances of isolated minor storms.

Today's estimated international sunspot number (ISN): 109, based on 14 stations.

Solar indices for 20 Apr 2023

Wolf number Catania	124
10cm solar flux	147
AK Chambon La Forêt	010
AK Wingst	006
Estimated Ap	004
Estimated international sunspot number	105 - Based on 19 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page