Viewing archive of Sunday, 12 September 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Sep 12 1236 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

No forecast

Solar protons

Quiet

	10cm flux	Ap
12 Sep 2021	088	007
13 Sep 2021	084	004
14 Sep 2021	082	004

Bulletin

The solar activity was at very low levels with no C-class flaring over the past 24 hours. NOAA 2863/Catania 37 (alpha) has now rotated over the west limb and NOAA 2864/Catania 38 (beta) is in the process of rotating. The remaining three active regions on the visible solar disc, namely NOAA 2866/Catania 40 (beta), NOAA 2868/Catania 39 (beta) and NOAA 2869/Catania 41 (beta) have produced only B-class flaring. The X-ray activity is expected to be at very low to low levels for the next 24 hours with 50% change for C-class flaring.

No Earth-directed CMEs were detected in the available coronagraph imagery over the past 24 hours. The newly available LASCO data shows that the long duration C1.1-class flare from NOAA 2868 (peak time at 21:34 UTC) on Sept 10th has resulted in an eruption with significant dimming. Slightly faster eruptions appear to have potentially followed the impulsive B6.8-class flare from NOAA 2869 (peak the at 07:28 UTC) and B5.4-class flare from NOAA 2868 (peak the at 07:43 UTC) on Sept 11th. Those eruptions are currently estimated to miss the Earth.

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours and is expected to remain so in the next 24 hours. The greater than 2MeV electron flux was below the 1000 pfu threshold and is expected to remain so in the next 24 hours. The 24h fluence for the greater than 2MeV electron flux was at nominal levels and is expected to remain so in the next 24 hours.

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) have been mostly at background solar wind levels. The solar wind speed varied between to 296 and 370 km/s. The total magnetic field remained slightly elevated at the beginning of the interval with values in the range of 2 to 13 nT. The Bz component was mostly positive, varying between -8 and 10.5 nT. The interplanetary magnetic field was mostly in the positive sector.

The geomagnetic conditions over the past 24 hours were globally quiet and locally quiet to unsettled. Mostly quiet geomagnetic conditions are expected for the next 24 hours with possible isolated unsettled periods later today.

Today's estimated international sunspot number (ISN): 050, based on 17 stations.

Solar indices for 11 Sep 2021

Wolf number Catania	///
10cm solar flux	092
AK Chambon La Forêt	010
AK Wingst	009
Estimated Ap	008
Estimated international sunspot number	072 - Based on 16 stations

Noticeable events summary

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

All times in UTC

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