Viewing archive of Sunday, 21 April 2024

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2024 Apr 21 1231 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
21 Apr 2024	212	016
22 Apr 2024	210	019
23 Apr 2024	208	017

Solar Active Regions and flaring

Solar flaring activity was at low levels, with multiple C-class flares recorded in the past 24 hours. The largest flare of the period was an C7.5 flare, peaking at 17:06 UTC on Apr 20, associated with NOAA AR 3645 (beta). There are currently 13 numbered active regions on the visible disk. NOAA AR 3647 (beta-delta) and NOAA AR 3639 (beta-gamma) are the most complex active regions on disk but were inactive. Low flaring activity was also produced by NOAA AR 3638 (beta class). Other regions on the disc have simple configuration of their photospheric magnetic field (alpha and beta) and did not show any significant flaring activity. The solar flaring activity is expected to be at low to moderate levels over the next 24 hours, with M-class flares possible and a small chance for X-class flare.

Coronal mass ejections

No Earth-directed CMEs have been detected in the available coronagraph imagery over the past 24 hours.

Solar wind

Over the past 24 hours, the solar wind parameters reflected the waning influence of the ICME. The total magnetic field was below 6 nT. The solar wind speed ranged between 420 km/s and 490 km/s. The southward component of the interplanetary magnetic field fluctuated between -5 nT and 4 nT. The interplanetary magnetic field phi angle varied between being directed towards the Sun to being directed away from the Sun. The solar wind conditions are expected to continue its return to the slow solar wind regime in the next 24 hours with a chance for a weak enhancement on Apr 21-23 due to the arrival of a high-speed stream from a negative polarity coronal hole and anticipated arrival of CMEs from Apr 17 - Apr 18, however with low confidence.

Geomagnetism

Geomagnetic conditions were quiet to unsettled both globally and locally (NOAA-Kp and K-BEL: 2 to 3) during the last 24 hours. Predominantly unsettled geomagnetic conditions are expected on Apr 21-23 with a chance of reaching active and minor storm conditions due to expected HSS arrival and potential CMEs arrivals.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to remain so with possible enhancements in case of increased levels of solar activity over the next days.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by the GOES-16 satellite, remained below the 1000 pfu threshold. It is expected to remain below the threshold during the next 24 hours. The 24 hour electron fluence was at normal levels and is expected to remain at these levels for the following 24 hours.

Today's estimated international sunspot number (ISN): 219, based on 13 stations.

Solar indices for 20 Apr 2024

Wolf number Catania	///
10cm solar flux	///
AK Chambon La Forêt	///
AK Wingst	///
Estimated Ap	///
Estimated international sunspot number	224 - Based on 21 stations

Noticeable events summary

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

All times in UTC

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