Viewing archive of Wednesday, 18 September 2024

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2024 Sep 18 1242 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
18 Sep 2024	167	008
19 Sep 2024	168	013
20 Sep 2024	166	008

Solar Active Regions and flaring

Solar flaring activity over the past 24 hours remained at low levels with background low C-class flaring. The largest activity was C3.9-flare with peak time 12:33 UTC on Sept 17th associated with NOAA AR 3824 (beta-gamma). There are seven numbered regions on the visible solar disc with NOAA AR 3825 (beta-gamma) being the largest and most complex region, which exhibited further flux emergence and magnetic field reconfiguration. Most of the flaring activity was produced by NOAA AR 3828 (alpha), NOAA AR 3824 and NOAA AR 3825. The solar flaring activity is likely to be at low to moderate levels over the coming days with 60% chances of M-class flares and 15% chances for isolated X-class flaring.

Coronal mass ejections

No Earth-directed coronal mass ejections (CMEs) have been detected in the available coronagraph imagery over the past 24 hours.

Coronal holes

A flat and narrow positive polarity mid-latitude coronal hole continues to reside on the central meridian. A mild high speed stream associated to this coronal hole could reach Earth on Sept 20th through Sept 22nd.

Solar wind

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) were indicative of the waning influence of an ICME arrival. The interplanetary magnetic field was mildly elevated reaching values of 12.9 nT with Bz as low as - 9.7 nT. The solar wind velocity varied in the range of 397 km/s to 557 km/s. The B field phi angle remained in the positive sector (directed away from the Sun). The solar wind conditions are expected to experience further decline towards nominal slow solar wind regime before registering slight enhancements from two possible high speed stream arrivals on Sept 18th - Sept 20th.

Geomagnetism

The geomagnetic conditions over the past 24 hours were predominantly quiet to active with a single moderate storm level as registered by the NOAA Kp index of 6- between 12:00 and 15:00 UTC on Sept 17th. Locally over Belgium only quiet to active conditions were observed. Mostly quiet to active geomagnetic conditions with small chances for isolated minor storms are expected over the next days with possible two mild high speed stream arrivals on Sept 18th - Sept 20th.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux has gradually decreased from minor radiation storm levels to below the 10 pfu threshold. The greater than 10 MeV GOES proton flux is expected to fully return towards backgrounds levels over the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux as measured by GOES 16 and GOES 18 were below the 1000 pfu threshold over the past 24 hours and is expected to remain so over the next 24 hours. The 24h electron fluence was nominal levels and is expected to remain so in the next 24 hours.

Today's estimated international sunspot number (ISN): 109, based on 18 stations.

Solar indices for 17 Sep 2024

Wolf number Catania	150
10cm solar flux	165
AK Chambon La Forêt	034
AK Wingst	054
Estimated Ap	058
Estimated international sunspot number	141 - 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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