Viewing archive of Friday, 21 May 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 May 21 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
21 May 2021	072	013
22 May 2021	074	010
23 May 2021	076	007

Bulletin

Solar activity has been very low, only one active region visible: NOAA AR 2824 (Catania 96, alpha magnetic field configuration). Only B-class flares seen in 24 hours, some of them from a new active region rotating into view from the east limb, solar activity may increase as a result in the coming 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, it is expected to increase in the coming 24 hours. The 24-hour electron fluence was at normal levels in the past 24 hours, it is expected to increase in the coming 24 hours.

A high speed solar wind (HSS) stream arrived to the Earth in the past 24 hours. The speed increased to 600 km/s, with interplanetary magnetic field magnitudes up to 19 nT, with Bz reaching - 13 nT. The polarity of the magnetic field was mostly negative (towards the Sun). The solar wind speed is still elevated, but the magnetic field intensity has reduced to about 4 nT. Similar conditions are expected for the next 24 hours.

Geomagnetic conditions have reached minor storm levels (KDourbes 2-5, Kp 2-5) due to the HSS effect. Mostly unsettled conditions, with possible active periods, can be expected for the next 24 hours.

Today's estimated international sunspot number (ISN): 013, based on 19 stations.

Solar indices for 20 May 2021

Wolf number Catania	026
10cm solar flux	072
AK Chambon La Forêt	035
AK Wingst	028
Estimated Ap	027
Estimated international sunspot number	018 - 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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