Viewing archive of Monday, 17 March 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Mar 17 1237 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
17 Mar 2025	190	016
18 Mar 2025	194	013
19 Mar 2025	198	005

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with C-class flares identified. The largest flare was a C7.8 flare peaking on March 17 at 05:42 UTC, which was produced by SIDC Sunspot Group 405 (NOAA Active Region 4028). This region along with SIDC Sunspot Groups 436 and SIDC 440 (NOAA Active Region 4025 and 4031) are the largest and most complex regions on disk. There are currently a total of 13 numbered sunspot groups on disk. Solar flaring activity is expected to be moderate over the next 24 hours, with C-class flares expected and M-class flares likely.

Coronal mass ejections

An eruption seen in SDO/AIA imagery from 08:52 UTC in the northern hemisphere is likely associated with a faint Coronal Mass Ejection seen in SOHO/LASCO-C2 data from 10:50 UTC March 16. This CME is directed to the north-west and predominantly above the sun Earth and is therefore not expected to impact Earth. A faint partial halo CME was observed to the north-east first seen in SOHO/LASCO-C2 data from 20:12 UTC March 16, coinciding with a narrower CME to the north. Initial analysis suggested the narrower CME maybe associated with an on disk eruption while the partial halo may be associated with a back-sided event.

Solar wind

The solar wind conditions reflected the waning high speed stream influence. The solar wind speed decreased from 450 to 400 km/s. The interplanetary magnetic field ranged between 5 and 7 nT with a minimum Bz value of -5 nT. The solar wind speed is expected to be slightly elevated on March 17 and 18, due to the influence of the high-speed stream associated with the negative polarity coronal hole which began to cross the central meridian March 13.

Geomagnetism

In the past 24 hours, geomagnetic conditions were quiet to unsettled (Kp = 3) with an isolated active period as measured by K bel. Geomagnetic conditions are expected to be at quiet to unsettled levels with intervals of active periods possible on March 17 and 18 due to the continued possible high-speed stream effects.

Proton flux levels

The greater than 10 MeV proton flux as measured by GOES-18 remained below the 10 pfu threshold and is expected to remain so over the next days.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux exceeded the 1000 pfu threshold for most the past 24 hours and is expected to be above the threshold during the next 24 hours. The 24h electron fluence was at moderate levels and is expected to remain so.

Today's estimated international sunspot number (ISN): 199, based on 08 stations.

Solar indices for 16 Mar 2025

Wolf number Catania	///
10cm solar flux	186
AK Chambon La Forêt	019
AK Wingst	011
Estimated Ap	011
Estimated international sunspot number	205 - 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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