Viewing archive of Friday, 17 December 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Dec 17 1244 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
17 Dec 2021	118	005
18 Dec 2021	119	005
19 Dec 2021	117	005

Bulletin

Seven regions are present on the visible solar disk, of which Catania 84/NOAA 2907, Catania 85/NOAA 2906 and Catania 87/NOAA 2909 produced C class flares while newly numbered NOAA 2911 produced a M1.2-class flare on Dec 17 00:39UT. C class flares can be expected and M class flares possible over the next 24 hours.

No Earth directed CMEs were observed in the past 24 hours.

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours and is expected to remain at nominal levels in the next 24 hours, depending the flaring activity. The greater than 2 MeV electron flux remained below the 1000 pfu alert threshold and is expected to have values about this level during the next 24 hours. The greater than 2 MeV electron fluence was at nominal levels in the past 24 hours where it is expected to remain.

Over the past 24 hours, the disturbance in solar wind parameters (ACE+DSCOVR) was waining down. The total magnetic field decreased from 6 to 1 nT, and its southward component, Bz, fluctuated between -4 nT and +5 nT. The solar wind speed dropped to 380 km/s. The interplanetary magnetic field phi angle has been predominantly on the negative sector (directed towards the Sun). Over the next 24 hours, we are expecting the return towards background levels to continue.

Geomagnetic conditions were quiet to unsettled over the past 24 hours (NOAA Kp 0-2 and K-BEL 0-3). Geomagnetic conditions are expected to be quietly to unsettled over the next 24 hours.

Today's estimated international sunspot number (ISN): 103, based on 10 stations.

Solar indices for 16 Dec 2021

Wolf number Catania	118
10cm solar flux	118
AK Chambon La Forêt	014
AK Wingst	008
Estimated Ap	008
Estimated international sunspot number	099 - Based on 17 stations

Noticeable events summary

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

All times in UTC

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