Viewing archive of Monday, 13 September 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Sep 13 1237 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
13 Sep 2021	088	011
14 Sep 2021	085	012
15 Sep 2021	083	004

Bulletin

The solar activity was at very low levels with no C-class flaring over the past 24 hours. NOAA Active Region (AR) 2866 (Catania group 40) is decaying slowly and is expected to continue to decay. NOAA AR 2868 (Catania group 39) is on the process of rotating away from Earth view. NOAA AR 2869 also shows signs of decay. The chance of a C-type flare over the next 24 hours is estimated to be approximately 50%.

No Earth-directed CMEs were detected in the available coronagraph imagery over the past 24 hours. The large eruptions detected both by LASCO-C2/SOHO and COR2/STEREO-A on 12 Sept 15:00 UT are back-sided. A small eruption detected by COR2/STEREO-A on 12 Sept around 17:00 UT appears too slow to be be geo-effective but, there are not enough data yet for a reliable estimation.

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) indicate the arrival of a weak ICME (as forecasted on the Sept 10). The solar wind speed gradually increased for 330 to 510 km/s. The total magnetic field varied between 6.4 and 10 nT, while the Bz varied -7.5 and 8.6 nT, but was mostly negative. The interplanetary magnetic field remain positive (directed away from the Sun) throughout the last 24 hours. The solar wind parameters are expected to remain at this level for the most of part of the next 24 hours and then gradually return to a typical slow solar wind regime.

The geomagnetic conditions over the past 24 hours were both globally and locally quiet to unsettled (NOAA Kp and K Dourbes 1-3). They are expected to remain unsettled over the next 24 hours and possibly reach active levels.

Today's estimated international sunspot number (ISN): 032, based on 19 stations.

Solar indices for 12 Sep 2021

Wolf number Catania	///
10cm solar flux	088
AK Chambon La Forêt	011
AK Wingst	006
Estimated Ap	006
Estimated international sunspot number	049 - Based on 23 stations

Noticeable events summary

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

All times in UTC

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