Viewing archive of Tuesday, 14 September 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Sep 14 1230 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
14 Sep 2021	084	007
15 Sep 2021	083	004
16 Sep 2021	080	001

Bulletin

The solar activity was at low levels with a single C-class flare over the past 24 hours. NOAA Active Region (AR) 2866 (Catania group 40) produced the C-class flare today 06:53 UT, but its magnetic progress cannot be easily estimated as it is close to the disk's edge. NOAA AR 2868 (Catania group 39) will rotate out of Earth's view in the next 24 hours hence the chances of detectable activity are reduced. An isolated C-class flare is possible in the next 24 hours, but not most likely.

A Coronal Mass Ejection (CME) that was observed by LASCO-C2/SOHO and COR2/STEREO in Sep 13 12:00 UT is likely to be geo-effective. Based on COR2 observations, its speed is estimated to be 300 km/s and it is expected to reach Earth around the Sep 18. A smaller CME detected by LASCO-C2/SOHO in Sep 14 around 06:00 UT, is also expected to reach Earth, possibly in the same day (Sep 18).

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.

The Solar Wind (SW) parameters measured by ACE and DSCOVR show that the Earth's environment is still under the influence of the ICME that arrived in Sep 13. The solar wind speed varied between 430 and 520 km/s in the past 24 hours. The total magnetic field varied between 3.7 and 9.2 nT and the Bz magnetic field component between -6.5 and 5.7 nT during the last 24 hours. The interplanetary magnetic field remained positive (directed away from the Sun) throughout the last 24 hours. The solar wind parameters are expected to remain at this level for a large part of the next 24 hours and then change 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 0-3). They are expected to maintain the same variety in values in the next 24 hours, as the solar wind conditions are not expected to change.

Today's estimated international sunspot number (ISN): 023, based on 21 stations.

Solar indices for 13 Sep 2021

Wolf number Catania	036
10cm solar flux	083
AK Chambon La Forêt	019
AK Wingst	010
Estimated Ap	011
Estimated international sunspot number	032 - Based on 28 stations

Noticeable events summary

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

All times in UTC

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