Viewing archive of Saturday, 20 March 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Mar 20 1233 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 Mar 2021	075	029
21 Mar 2021	075	022
22 Mar 2021	076	019

Bulletin

Solar activity was at very low levels in the past 24 hours. NOAA active region 2810 (Catania group 81) remained magnetically simple and inactive. A new active region is expected to rotate onto the solar disk in the next 24 hours. Solar activity is expected to remain at very low levels, with a very small chance of a C-class flare.

A slow CME, with a speed of approximately 200 km/s, was seen in LASCO-C2 and STEREO-COR2 coronagraph imagery from 01:50 UT. This may be associated with a filament observed in the south-east quadrant of the solar disk from 00 UT Mar 20 in AIA SDO 304 imagery. Initial analysis suggests this CME may have an Earth directed component, with a predicted arrival time of late on Mar 24.

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

Solar wind conditions started to become enhanced from 00 UT 20 Mar due to the arrival of the high-speed stream associated with the extension to the southern Coronal Hole, which crossed the central meridian on Mar 17. The solar wind speed increased to the current value of 600 km/s, and the Bz component of the interplanetary magnetic field became predominantly negative from 05 UT with a minimum value of -20 nT. The total interplanetary magnetic field varied between 3 nT and 23 nT. The magnetic field phi angle was predominantly in the negative sector (directed towards the Sun). The solar wind parameters are expected to remain elevated until Mar 22, as the Earth remains under the influence of the high-speed stream.

Geomagnetic conditions increased from 06 UT Mar 20 and reached minor storm levels locally (K Dourbes = 5) and moderate storm levels for the planetary K index (NOAA Kp=6). Active conditions are expected for the next 48 hours, with further minor to moderate geomagnetic storms possible in response to any longer periods of negative Bz.

Today's estimated international sunspot number (ISN): 011, based on 21 stations.

Solar indices for 19 Mar 2021

Wolf number Catania	014
10cm solar flux	074
AK Chambon La Forêt	014
AK Wingst	008
Estimated Ap	007
Estimated international sunspot number	013 - Based on 28 stations

Noticeable events summary

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

All times in UTC

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