Viewing archive of Saturday, 21 August 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Aug 21 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
21 Aug 2021	077	007
22 Aug 2021	079	007
23 Aug 2021	081	007

Bulletin

One numbered active region is visible on the solar disk: NOAA 2858 (beta magnetic field configuration). There is a region that rotated over the east limb (unnumbered still) that produced 3 C-class flares in the past 24 hours, the strongest being a C3.0 flare peaking at 15:57 UT on 20 August. There is another region rotating into view in the southern hemisphere. More C-class flares can be expected, M-class flares are possible.

The AR rotating into view from the southern hemisphere produced a wide eastward CME first seen by LASCO C2 at 06:12 UT on 20 August. given the position of the source region behind the limb, this CME is not expected to affect the Earth. No Earth directed Coronal Mass Ejections (CMEs) were observed in the available coronagraphic imagery.

The southern extension of the north polar coronal hole has crossed central meridian today, a related high speed stream may arrive to the Earth in about 3 days.

The greater than 10 MeV proton flux was at background levels in the past 24 hours, and is expected to remain so in the next 24 hours. The greater than 2 MeV electron flux remained below the 1000 pfu alert threshold, while the 24h electron fluence was at normal levels over the past 24 hours. Over the next 24 hours they are expected to remain at those levels.

Over the past 24 hours the solar wind speed has been around 350 km/s. The total magnetic field strength varied between 2 and 8 nT, with positive polarity (directed away from the Sun). Similar slow solar wind conditions are expected for the next 24 hours.

Geomagnetic conditions were at quiet to unsettled levels (NOAA Kp 0-2 and K Dourbes 0-3) over the past 24 hours. Similar conditions are expected over the next 24 hours.

Today's estimated international sunspot number (ISN): 015, based on 16 stations.

Solar indices for 20 Aug 2021

Wolf number Catania	015
10cm solar flux	078
AK Chambon La Forêt	007
AK Wingst	006
Estimated Ap	006
Estimated international sunspot number	013 - Based on 27 stations

Noticeable events summary

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

All times in UTC

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