Viewing archive of Thursday, 18 March 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Mar 18 1232 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
18 Mar 2021	078	006
19 Mar 2021	077	019
20 Mar 2021	078	028

Bulletin

Solar activity was very low in the past 24 hours. NOAA Active Region (AR) 2810 (alpha) is the only active region on disk and has been quiet. Solar activity is expected to remain at very low levels, with a small chance of a c-class flare.

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 first part of the period before gradually decreasing. The greater than 2 MeV electron flux is expected to again briefly exceed the 1000 pfu threshold during the next 24 hours. The 24h electron fluence was at moderate levels and it is expected to be at nominal to moderate levels in the next 24 hours.

Solar wind conditions reflected a slow solar wind regime over the last 24 hours. The solar wind speed ranged between 310 km/s and 360 km/s. The total interplanetary magnetic field varied between 0 and 7 nT. The magnetic field phi angle was predominantly in the positive sector (directed away from the Sun). Solar wind conditions are expected to continue reflect a slow solar wind regime on Mar 18. The solar wind parameters are expected to become enhanced from late on Mar 19, due to the effect from the corotating interaction region (CIR) and high-speed stream associated with the negative polarity coronal hole, which crossed the central meridian on Mar 17.

Geomagnetic conditions were mostly at quiet levels with local unsettled periods (NOAA Kp 1-2 and local K Dourbes 1-3). Geomagnetic conditions are expected to be at quiet levels over the next 24 hours. However, the geomagnetic conditions are expected to reach active levels from late on the Mar 19, with minor storm conditions possible on Mar 20, due to the arrival of the expected high-speed stream.

Today's estimated international sunspot number (ISN): 012, based on 11 stations.

Solar indices for 17 Mar 2021

Wolf number Catania	011
10cm solar flux	078
AK Chambon La Forêt	009
AK Wingst	005
Estimated Ap	003
Estimated international sunspot number	012 - Based on 19 stations

Noticeable events summary

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

All times in UTC

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