Viewing archive of Friday, 24 September 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Sep 24 1343 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
24 Sep 2021	090	013
25 Sep 2021	090	010
26 Sep 2021	089	012

Bulletin

Multiple regions present on the sun with most magnetically complex the Catania 45/NOAA 2871, source of a M1.8 class flare. Over the next 24 hours, C-class flares can be expected with a slight possibility of further M class.

A CME associated with the M2.9 class flare on Sep 23 04:27UT may arrive from Sep 26 22:57UT.

The greater than 10 MeV proton flux was at background levels in the past 24 hours, and is expected to stay at nominal levels in the next 24 hours. The greater than 2 MeV electron flux remained below the 1000 pfu alert threshold. Over the next 24 hours, it is expected to increase towards the threshold. The 24h electron fluence was at nominal levels over the past 24 hours. Over the next 24 hours they are expected to remain at those levels, increasing towards moderate levels.

Over the past 24 hours the solar wind speed increased, reaching from 510 km/s. The total magnetic field strength had values between 1 and 9 nT, while its Bz component varied between -6 and 7nT. The interplanetary magnetic field phi angle has predominantly been on the negative sector (directed towards the the Sun). We seem to be under the influence of the high speed stream associated with the negative coronal hole, crossing central meridian Sep 21 and the CME 19 seemed to have an impact about Sep 23 12:00UT. An extension of the northern positive coronal hole is presently at central meridian. Solar wind parameters are expected to remain ehanced.

Geomagnetic conditions were at quiet to unsettled levels, (NOAA Kp 1-2 and K Dourbes 0-2) over the past 24 hours. Unsettled conditions with possibility of active events can be expected over the next 24 hours.

Today's estimated international sunspot number (ISN): 061, based on 15 stations.

Solar indices for 23 Sep 2021

Wolf number Catania	///
10cm solar flux	090
AK Chambon La Forêt	014
AK Wingst	010
Estimated Ap	011
Estimated international sunspot number	068 - Based on 20 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page