Viewing archive of Sunday, 21 March 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Mar 21 1231 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
21 Mar 2021	081	017
22 Mar 2021	080	018
23 Mar 2021	082	016

Bulletin

Solar activity was at very low levels in the past 24 hours. NOAA Active Region (AR) 2810 (Catania group 81) has decayed to a plage region. A new active region, NOAA AR 2811, has rotated onto the solar disk near N20E70 and has produced some low-level B-class flaring. Another active region is also expected to rotate onto the disk in the next 24 hours. Solar activity is expected to remain at very low levels, with a small chance of a C-class flare.

The Coronal Mass Ejection (CME) first reported on Mar 20, seen in LASCO-C2 and STEREO-COR2 coronagraph imagery from 01:45 UT and attributed to a filament eruption in the south east quadrant, has been further analysed and a possible glancing blow at Earth is predicted on Mar 23 to early on Mar 24. No other Earth-directed CMEs have been observed in the available coronagraph data.

The greater than 10 MeV proton flux was at nominal levels over the past 24 hours and is expected to remain so for the next 24 hours. The greater than 2 MeV electron flux remained just below the 1000 pfu threshold during the past 24 hours. The greater than 2 MeV electron flux is expected to increase and likely exceed the 1000 pfu threshold for a short period during the next 24 hours. The 24h electron fluence was at nominal levels in the last 24 hours and is expected to be at nominal to moderate levels in the next 24 hours.

Solar wind conditions remained enhanced over the past 24 hours as the Earth remained under the influence of the high-speed stream associated with the negative polarity coronal hole, which crossed the central meridian on Mar 17. The solar wind speed ranged between 550 and 680 km/s. The total interplanetary magnetic field varied between 2 and 7 nT, with a minimum recorded Bz value of -5 nT. The magnetic field phi angle was predominantly in the negative sector (directed towards the Sun). The solar wind parameters are expected to remain elevated on Mar 21 and Mar 22, as the Earth remains under the influence of the high-speed stream. A glancing blow from the CME on Mar 20 may also cause an enhancement in the solar wind on Mar 23.

Geomagnetic conditions were at quiet to active levels (NOAA Kp and local K Dourbes 1-4) over the past 24 hours. Quiet to active conditions are expected for the next 48 hours, with an isolate period of minor geomagnetic storms possible in response to any longer periods of negative Bz.

Today's estimated international sunspot number (ISN): 012, based on 05 stations.

Solar indices for 20 Mar 2021

Wolf number Catania	///
10cm solar flux	080
AK Chambon La Forêt	048
AK Wingst	025
Estimated Ap	030
Estimated international sunspot number	011 - Based on 28 stations

Noticeable events summary

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

All times in UTC

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