Viewing archive of Wednesday, 15 December 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Dec 15 1250 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
15 Dec 2021	089	011
16 Dec 2021	093	011
17 Dec 2021	100	005

Bulletin

Regions Catania 82, Catania 83/NOAA 2905, NOAA 2906,Catania 84/NOAA 2907 are present on the visible solar disk as well as newly emerged regions Catania 86 and 87 on SE. One more region is about to rotate on the visible disk on NE. Region Catania 84 was the source of a series of C-class flares, with stronger output that of a C6-class, recorded by GOES on Dec 14 23:44UT. Regions Catania 84,86,87 and NOAA 2906 while be monitored for flare activity. C class flares can be expected and M class flares possible over the next 24 hours.

A filament eruption can be seen in AIA304 at Dec 14 12:08UT at location about N45W05 with a possibly associated, faint Coronal Mass Ejection (CME) seen in Stereo A Dec 14 18:09UT. More will be reported as more data become available.

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 slowly start increasing but remain below this level during the next 24 hours. The greater than 2 MeV electron fluence was at nominal levels in the past 24 hours and is expected to slowly start increasing towards moderate levels.

According to the values of the solar wind parameters (ACE+DSCOVR), over the past 24 hours, the expected high-speed stream (HSS) emanating from the small equatorial negative polarity Coronal Hole (CH) that appeared on Dec 12 seems has arrived at about Dec 15 02:40UT. The total magnetic field reached 16 nT, and its southward component, Bz, fluctuated between -15 nT and +14 nT in the past 24 hours (note an hour data gap on Dec 15 03:22-04:23UT). The solar wind speed increased up to 565 km/s. The interplanetary magnetic field phi angle has been on the negative sector (directed towards the the Sun) since Dec 14 18:30UT. The HSS from the southern negative polarity CH crossed central meridian on Dec 13 should add up to those effects over the next 24 hours.

Geomagnetic conditions were quiet to unsettled over the past 24 hours (NOAA Kp 0-3 and K-BEL 0-2). Geomagnetic conditions are expected to be quiet to unsettled over the next 24 hours with a possibility of isolated active periods in response to the influence of the HSS.

Today's estimated international sunspot number (ISN): 076, based on 09 stations.

Solar indices for 14 Dec 2021

Wolf number Catania	///
10cm solar flux	089
AK Chambon La Forêt	009
AK Wingst	005
Estimated Ap	005
Estimated international sunspot number	043 - Based on 17 stations

Noticeable events summary

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

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