Viewing archive of Sunday, 5 September 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Sep 05 1248 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
05 Sep 2021	087	016
06 Sep 2021	086	015
07 Sep 2021	085	007

Bulletin

X-ray flux remained below C level throughout the period. The bipolar region NOAA 2863 in the central South appears stable and inactive, and has lost most of its trailing spots. Of the two bipolar regions in the North whose emergence was reported yesterday (NOAA regions 2864 and 2865), NOAA region 2865 was shortlived and already decayed into plage. Another shortlived emergence was recorded in the South West (briefly numbered as NOAA 2867). Meanwhile, in the SouthEast apart from the region that rotated onto the disc yesterday (numbered NOAA 2866) and that evolved into a bipolar region, also another bipolar region emerged just to the West of it (to be numbered NOAA 2868). All in all there are thus 4 bipolar regions on disc but none of them appears to be very complex. X-ray flux is expected to remain below C level, although with the several regions on disc there always remains a chance for C-flaring.

A dimming and EUV wave can be seen to the South of active region 2864 starting around 20:07UT. This is indicative a CME initiation that is likely to have an Earth directed component. Coronagraph images are being annalysed to assess and forecast a possible CME arrival. No other Earth directed CMEs were observed in available coronagraph data.

The greater than 10 MeV proton flux was at background levels and we expect it will remain so in the next 24 hours. The greater than 2 MeV electron flux remained below the 1000 pfu threshold. The 24h electron fluence is at normal levels and we expect it to be at normal levels over the next days.

Slow Solar wind conditions were recorded with Solar wind speed decaying to 300 km/s and interplanetary field hovering in the 4-6nT range. The orientation of the interplanetary magnetic field was away from the Sun. Solar wind may still see some weak enhancements today and tomorrow associated to a negative polarity coronal hole in the Southern hemisphere.

Geomagnetic conditions were quiet to unsettled (NOAA Kp 1-3 and local K Dourbes 0-3) and are expected to remain so with possibly active periods should the possible moderate Solar wind still set trough.

Today's estimated international sunspot number (ISN): 077, based on 22 stations.

Solar indices for 04 Sep 2021

Wolf number Catania	///
10cm solar flux	087
AK Chambon La Forêt	010
AK Wingst	006
Estimated Ap	006
Estimated international sunspot number	068 - Based on 27 stations

Noticeable events summary

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

All times in UTC

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