Viewing archive of Thursday, 20 May 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 May 20 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
20 May 2021	076	028
21 May 2021	076	007
22 May 2021	077	007

Bulletin

Two active regions (ARs) visible on the disk, NOAA AR 2822 (Catania 93, alpha magnetic field configuration, rotating over the west limb) and AR 2824 (Catania 96, decayed to alpha magnetic field configuration). Solar activity is very low, only B-class flares were seen in the past 24 hours. The situation is expected to remain the same for the next 24 hours.

No Earth-directed Coronal Mass Ejections (CMEs) have been detected in the available coronagraphic imagery in the last 24 hours.

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 below the 1000 pfu in the past 24 hours and is expected to remain so. The 24-hour electron fluence was at normal levels in the past 24 hours and is expected to remain so.

In the last hours, the solar wind speed has shown a gradual increase from about 320 km/s to 410 km/s, accompanied by similar increases in density and strong magnetic fields (with intensity up to 17 nT and Bz reaching -13 nT). This marks the arrival of the high speed stream from the coronal hole that crossed central meridian late on May 15. The interplanetary magnetic field polarity was mostly negative (towards the Sun). The solar wind speed is expected to increase more in the next 24 hours.

Geomagnetic conditions have been quiet to unsettled (KDourbes 1-3, Kp 1-3). Minor storm periods, and up to isolated major storm periods, can be expected due to the high speed solar wind stream arriving to the Earth.

Today's estimated international sunspot number (ISN): 019, based on 23 stations.

Solar indices for 19 May 2021

Wolf number Catania	037
10cm solar flux	076
AK Chambon La Forêt	014
AK Wingst	007
Estimated Ap	006
Estimated international sunspot number	025 - Based on 31 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