Viewing archive of Friday, 17 April 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 Apr 17 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
17 Apr 2026	110	007
18 Apr 2026	110	007
19 Apr 2026	110	007

Solar Active Regions and flaring

A total of 3 numbered sunspot groups were identified on the disk over the past 24 hours. Solar flaring activity was low over the past 24 hours, with only C-class flares identified. These flares originated at SIDC Sunspot Group 825 (NOAA Active Regions 4397, 4419), currently located at N15E38, with a Beta-Gamma magnetic configuration. The largest flare was a C4.1 flare (SIDC Flare 7416) peaking on April 17 at 04:42 UTC, which was produced by SIDC Sunspot Group 825. More c-class flares can be expected in the next 24 hours, and there are low chances of observing an M-class flare.

Coronal mass ejections

No Earth directed CMEs were observed in the past 24 hours.

Coronal holes

There is a large equatorial coronal hole with negative polarity in the western hemisphere (SIDC Coronal Hole 147).

Solar wind

The solar wind speed is low, around 310 km/s with interplanetary magnetic field magnitude of 5 nT, with positive polarity (away from the Sun). The high speed solar wind stream from a large coronal hole located in the northern hemisphere (SIDC Coronal Hole 147) will reach the Earth in about 24 hours.

Geomagnetism

Geomagnetic conditions have been quiet (Kp and K_BEL up to 2). Similar conditions can be expected for the next 24 hours, after that the high speed stream from SIDC Coronal Hole 147 will reach the Earth and create disturbed conditions.

Proton flux levels

The greater than 10 MeV proton flux, as measured by GOES-18, was below the 10 pfu threshold level over the past 24 hours and is expected to remain so for the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by GOES-18 and GOES-19 was briefly above the 1000 pfu alert threshold in the past 24 hours. The flux is expected to fluctuate around the alert threshold over the next 24 hours. The 24-hour electron fluence was at normal to moderate levels over the past 24 hours and is expected to remain at these levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 051, based on 20 stations.

Solar indices for 16 Apr 2026

Wolf number Catania	///
10cm solar flux	108
AK Chambon La Forêt	006
AK Wingst	003
Estimated Ap	002
Estimated international sunspot number	054 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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