Viewing archive of Saturday, 17 April 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Apr 17 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
17 Apr 2021	077	032
18 Apr 2021	078	018
19 Apr 2021	077	011

Bulletin

Solar activity remained at very low levels over the last 24 hours. Three numbered sunspot groups are visible on the solar disk, namely Catania 86 (NOAA 2814), NOAA 2815 and NOAA 2016. All of them are classified as magnetic type Beta and have shown low levels of activity with B-class flaring. The flaring activity within the next 24 hours is expected to remain low with 30% chance for C-class flares.

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 show some enhancement. The 24h electron fluence was at nominal levels and is expected to be at nominal to moderate levels in the next 24 hours.

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) were elevated with the arrival of the high speed stream (HSS) from the high- latitude extension of the negative-polarity polar coronal hole. The total magnetic field registered a magnitude of 13 nT with a minimum Bz of -11 nT. The solar wind speed varied between 400 km/s and 610 km/s. The solar wind speed is expected to remain elevated throughout April 17th.

Due to the HSS and prolonged intervals with negative Bz multiple periods with minor geomagnetic storms were registered over the past 24 hours. Unsettled to active geomagnetic conditions with more periods of minor geomagnetic storms can be expected for the next 24 hours.

Today's estimated international sunspot number (ISN): 019, based on 21 stations.

Solar indices for 16 Apr 2021

Wolf number Catania	///
10cm solar flux	077
AK Chambon La Forêt	038
AK Wingst	020
Estimated Ap	020
Estimated international sunspot number	037 - Based on 26 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