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Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2021 Feb 21 1231 UTC

SIDC Forecast

Brillamenti solari

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

Minor storm expected (A>=30 or K=5)

Protoni solari

Quiet

	10cm flux	Ap
21 Feb 2021	076	021
22 Feb 2021	076	021
23 Feb 2021	075	017

Bulletin

The solar activity has been mostly quiet over the past 24 hours. The sunspot (Catania 73, NOAA-AR 2803) remained quiet on the visible solar disc without any significant flaring activity. The solar flaring activity is expected to remain at low levels for the next 24 hours with very small chances of C-class flare from the sunspot.

A filament located around -15 degree longitude and -20 degree latitude erupted on February 20, 2021, around 10:00 UTC. A partial-halo Coronal Mass Ejection (with and angular width of about 152 degree) was then observed on SOHO/LASCO-C2 coronagraph images around 11:30 UTC. The CME projected speed was estimated between 300 km/s and 500 km/s. We estimated the true speed to be higher up to 900 km/s. Since the filament was located close to the central meridian of the solar disc, we expected the CME to impact Earth in about 2 days.

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours and is expected to remain so in the next 24 hours. The greater than 2 MeV electron flux increase and passed the 1000 pfu threshold. The electron flux is expected to remain high due to the enhancement of the solar wind conditions.

Over the past 24 hours, the Earth was under the influence of the fast solar wind regime. The solar wind speed ranged between 550 km/s and 620 km/s. The total magnetic field ranged between 5 nT and 10 nT. The Bz component fluctuated between -8 nT and 7.5 nT being mostly negative. The fast solar wind streams associated with southern coronal holes (negative magnetic polarity) are expected to continue to influence the solar wind environment near Earth for the next days. A solar wind shock could also be observed within the next two days, due to the arrival of the interplanetary coronal mass ejection observed in the SOHO/LASCO-C2 coronagraph images.

The geomagnetic conditions over the past 24 hours were active, a minor storm was also measured in Dourbes (K-Dourbes=5) on February 20, between 19:00 and 20:00 UTC. The geomagnetic conditions are expected to remain active with possible periods of minor storm conditions (Kp and K-Dourbes equal to 5) in response to the enhancement of the solar wind parameters and possible prolonged periods of southward directed Bz component. Depending of the internal solar magnetic orientation of the interplanetary coronal mass ejection, the geomagnetic conditions may be impacted with a minor storm (Kp, and K-Dourbes equal to 5).

Today's estimated international sunspot number (ISN): 011, based on 15 stations.

Solar indices for 20 Feb 2021

Wolf number Catania	///
10cm solar flux	076
AK Chambon La Forêt	043
AK Wingst	///
Estimated Ap	027
Estimated international sunspot number	011 - Based on 24 stations

Noticeable events summary

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

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