Viewing archive of Wednesday, 17 March 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Mar 17 1230 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
17 Mar 2021	079	003
18 Mar 2021	077	004
19 Mar 2021	077	023

Bulletin

Solar activity was very low in the past 24 hours, no C-class flares were recorded. NOAA Active Region (AR) 2808 has decayed into a plage region. The new active region, is now numbered as Catania group 81 (NOAA AR 2810) and has been quiet. Overall, solar activity is expected to remain at very low levels, with a small chance of a C-class flare.

A back-sided partial halo Coronal Mass Ejections (CME) was first seen at 10:24 UT on the 16th March in LASCO-C2 images. It is not expected to arrive at Earth. No 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 exceeded the 1000 pfu threshold during the last 24 hours and is expected to remain above the threshold for the next 24 hours. The 24h electron fluence was at moderate levels and it is expected to remain at this level in the next 24 hours.

Solar wind speed continued to decrease in the last 24 hours with values between 400 km/s and 340 km/s. The total interplanetary magnetic field was between 0 and 6 nT during the last 24 hours. The magnetic field phi angle switched from negative to mostly positive after approximately 18:00 UT March 16th. Solar wind conditions are expected to generally reflect a slow solar wind regime during March 17th and 18th. On March 19th the solar wind high speed stream associated with the corona hole, which crossed that solar central meridian on 17th March, is expected to arrive.

Geomagnetic conditions were at quiet levels (NOAA Kp 0-2 and local K Dourbes 1-2). Geomagnetic conditions are expected to be at quiet levels over the next 24 hours. However, the geomagnetic conditions are expected to reach active levels on the 19th March, due to the expected high speed stream.

Today's estimated international sunspot number (ISN): 011, based on 11 stations.

Solar indices for 16 Mar 2021

Wolf number Catania	///
10cm solar flux	079
AK Chambon La Forêt	007
AK Wingst	003
Estimated Ap	002
Estimated international sunspot number	020 - Based on 20 stations

Noticeable events summary

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

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