Viewing archive of Friday, 23 July 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Jul 23 1235 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
23 Jul 2021	088	014
24 Jul 2021	084	006
25 Jul 2021	082	011

Bulletin

Solar activity was at very low levels over the past 24 hours. The six active regions on the visible disc have remained quiet. The most complex active region, Catania sunspot group 17/NOAA 2842 decreased its complexity from magnetic type beta-gamma to magnetic type beta and is expected to soon rotate over the west limb together with Catania sunspot group 20/NOAA 2845 (magnetic type beta). Catania sunspot group 22/NOAA 2846 and Catania sunspot group 21/NOAA 2848 have remained with magnetic type beta, while Catania sunspot group 20/NOAA 2847 has decreased its magnetic complexity to type beta. Catania sunspot group 24/NOAA 2849 remained magnetically simple type alpha and is no longer producing C-class flares. The X-ray flaring activity for the next 24 hours is expected to be at very low levels with a low probability for an isolated C-class flare.

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

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours and is expected to remain so in the next 24 hours. The greater than 2MeV electron flux remained under the 1000 pfu threshold and is expected to remain so. The 24h electron fluence was at nominal levels and is expected to remain in the next 24 hours.

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) have recovered from the enhancements due to the small positive polarity geo- effective coronal hole. The solar wind speed varied between 328 and 462 km/s. The total magnetic field remained weak in the range of 1.7 to 7.2 nT. The north-south (Bz) component weakly varied between -4.8 to +4 nT. The interplanetary magnetic field remained predominantly in the positive sector directed away from the Sun. The solar wind conditions might get slightly enhanced later today if a glancing blow from the July 20th CME reaches the Earth.

The geomagnetic conditions over the past 24 hours were mostly quiet with short isolated unsettled periods. Quiet to unsettled geomagnetic conditions are expected for the next 24 hour with possible active periods in case a glancing blow from the July 20th CME arrives to the Earth.

Today's estimated international sunspot number (ISN): 056, based on 22 stations.

Solar indices for 22 Jul 2021

Wolf number Catania	083
10cm solar flux	089
AK Chambon La Forêt	011
AK Wingst	009
Estimated Ap	010
Estimated international sunspot number	074 - Based on 32 stations

Noticeable events summary

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

All times in UTC

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