Viewing archive of Thursday, 23 September 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Sep 23 1251 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
23 Sep 2021	089	016
24 Sep 2021	090	016
25 Sep 2021	092	008

Bulletin

Over the past 24 hours, the regions reported yesterday have been present on the solar disk. One more unnamed region has appeared to the vicinity of the SE. A M2.9 flare originated from region Catania 45/NOAA 2871 (magnetic type beta-delta) has been recorded. Over the next 24 hours, C-class flares can be expected.

No Earth directed Coronal Mass Ejections (CMEs) have been conformed in the available coronagraphic imagery.

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 varied from 360 to 405 km/s. The total magnetic field strength had values between 2 and 6 nT, while its Bz component varied between -5 and 6 nT. The interplanetary magnetic field phi angle has been mainly on the positive sector (directed away from the Sun) with small variations. Solar wind parameters are expected to be further enhanced over the next 24 hours, in the small chance of the arrival of the CME from Sep 19 and effects of the high speed stream associated with the negative Coronal Hole present on Central Meridian. An extension of the northern positive coronal hole will cross central meridian tomorrow.

Geomagnetic conditions were at quiet to unsettled levels, with an active periods on Sep 23 06:00-09:00UT (NOAA Kp 1-4 and K Dourbes 1-3) 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): 076, based on 12 stations.

Solar indices for 22 Sep 2021

Wolf number Catania	///
10cm solar flux	089
AK Chambon La Forêt	016
AK Wingst	014
Estimated Ap	014
Estimated international sunspot number	080 - Based on 21 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