Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2026 Mar 17 1237 UTC

SIDC Forecast

Brillamenti solari

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

Geomagnetism

Quiet (A<20 and K<4)

Protoni solari

Quiet

	10cm flux	Ap
17 Mar 2026	112	013
18 Mar 2026	114	009
19 Mar 2026	116	022

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours. The largest flare was a M2.7 flare (SIDC Flare 7220) peaking on March 16 at 12:15 UTC, which was produced by group 820 (NOAA Active Region 4392). This region is the largest on disk, with Beta-Gamma magnetic configuration. This region also produced an M1.3 flare (SIDC Flare 7222), peaking on March 17 at 09:04 UTC. There are currently 5 numbered regions on the disk. The other regions are simple and mostly quiet. Solar flaring activity is expected to be low over the next 24 hours, with C-class flares expected and further isolated M-class flares possible.

Espulsioni di massa coronale

An asymmetric halo Coronal Mass Ejection (CME) was first detected in LASCO-C2 data from 12:36 UTC on March 16. This was associated with the M2.7 flare (SIDC Flare 7220) from SIDC sunspot group 820 (NOAA Active Region 4392) located near the central meridian. There was a large on disk dimming and Type II and Type IV radio emission associated with this event. The CME was relatively slow around 550 km/s and initial analysis suggests an arrival at Earth from late on March 19. A filament around S05W10 also began to lift off around 03:00 UTC March 17 but no CME is yet visible in the coronagraph data.

Fori coronali

The southern midlatitude extension of the large positive polarity coronal hole (SIDC Coronal Hole 154) is still crossing the central meridian.

Vento solare

Over the past 24 hours, the solar wind parameters reflected the waning influence of the high speed stream associated with SIDC Coronal Hole 154. The solar wind speed decreased from 550 kms to around 480 km/s. The total magnetic field was stable around 5 nT. Bz had a minimum of -4 nT. The interplanetary magnetic field phi angle was mostly in the positive sector (directed towards the Sun). The influence of the current high speed stream is expected to continue to decrease over the next 24 as the parameters gradually return to slow solar wind conditions.

Geomagnetism

Over the past 24 hours, the geomagnetic conditions reached unsettled levels globally and locally (NOAA KP 3 and K BEL 3). Quiet conditions are expected over the next 24 hours, with possible isolated unsettled to active conditions possible due to the ongoing high speed stream influence.

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold over the past 24 hours. It is expected to remain below this threshold level over the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by GOES-18 and GOES-19 satellites, exceeded the 1000 pfu threshold. The greater than 2 MeV electron flux is expected to again exceed the 1000 pfu threshold over the next 24 hours. The electron fluence was at normal to moderate levels and is expected to be at moderate levels for the next 24 hours.

Today's estimated international sunspot number (ISN): 063, based on 10 stations.

Solar indices for 16 Mar 2026

Wolf number Catania	///
10cm solar flux	111
AK Chambon La Forêt	014
AK Wingst	009
Estimated Ap	009
Estimated international sunspot number	076 - Based on 24 stations

Noticeable events summary

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