Viewing archive of Tuesday, 25 May 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 May 25 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
25 May 2021	073	024
26 May 2021	073	027
27 May 2021	073	008

Bulletin

The Sun has produced only B flares in the past 24 hours. The chance for a C flare in the next 24 hours is estimated at 40%, while the chance for an M flare is estimated at 5%, mainly from Beta-Gamma region NOAA 2824.

A CME towards the west was first observed at 17:47 UT on May 24 in LASCO C2, after a data gap. Assuming region 2824 is the source region, this CME is probably Earthbound, with an estimated speed of 500 km/s and arrival time around 21h UT on May 28.

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours, and is expected to stay at nominal levels in the next 24 hours. The greater than 2 MeV electron flux reached a daily maximum just above the 1000 pfu threshold, and is expected to reach a similar daily maximum in the next 24 hours. The greater than 2 MeV electron fluence has reached moderate levels during the past 24 hours, and is expected to return to normal levels in the next 24 hours.

Solar wind speed near Earth as registered by DSCOVR decreased from about 360 to 315 km/s in the past 24 hours. The Interplanetary Magnetic Field (IMF) was oriented towards the Sun and its magnitude varied between 1 and 4 nT. Solar wind speeds are expected to increase in the second half of May 25, with the arrival of several CMEs on May 25 and May 26.

Quiet geomagnetic conditions (K Dourbes between 0 and 1; NOAA Kp between 0 and 1) were registered in the past 24 hours. Minor storm intervals (K Dourbes = 5) are possible in the second half of May 25, on May 26 and on May 27, with a chance for moderate geomagnetic levels (K Dourbes = 6), due to the expected arrival of several CMEs.

Today's estimated international sunspot number (ISN): 037, based on 18 stations.

Solar indices for 24 May 2021

Wolf number Catania	041
10cm solar flux	073
AK Chambon La Forêt	005
AK Wingst	003
Estimated Ap	002
Estimated international sunspot number	029 - Based on 28 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page