Viewing archive of Sunday, 21 May 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 May 21 1231 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
21 May 2023	171	010
22 May 2023	173	015
23 May 2023	171	008

Solar Active Regions and flaring

Solar flaring activity remained at moderate levels over the past 24 hours with five M-class flares and several C-class flares being detected. The largest flare was an M8.9 flare, peaking at 12:35 UTC on May 20, associated with NOAA Active Region (AR) 3311(beta- gamma-delta class). AR 3311 remains the largest and most magnetically complex region on the solar surface and produced the majority of the flaring activity. Low flaring activity was also produced by NOAA AR 3305 (beta class) and 3312 (beta class).Other regions on the disc have simple configuration of their photospheric magnetic field (alpha and beta) and did not show any significant flaring activity. The flaring activity is expected to remain moderate with possible M-class flare and a chance of X-class flare.

Coronal mass ejections

Few coronal mass ejections (CME) and flows were observed in the available SOHO/LASCO coronagraph imagery and automatically detected by the Cactus tool over the past 24 hours. However, no clear Earth-directed coronal mass ejections were identified.

Coronal holes

An equatorial coronal hole of negative polarity started to transit the central meridian yesterday evening. An associated high speed stream in in-situ solar wind measurements is expected for Apr 24.

Solar wind

The solar wind environment near Earth was under the influence of the fast solar wind streams associated to the equatorial coronal hole of negative polarity. The solar wind speed has reached a maximum value of 620 km/s at around 00:50 UTC today, May 21 and has showed a gradually decreasing trend after that, decreasing to values of around 480 km/s. The total interplanetary magnetic decreased to the values around 4 nT. The southward interplanetary magnetic component, Bz, fluctuated between -7 nT and 4 nT. The magnetic field orientation was predominantly in the negative sector (field directed towards the Sun). The solar wind conditions are expected to remain elevated for the next days with a low probability for further minor enhancements from late on May 21, due to the CME associated with a filament eruption in the southwest sector on May 17th, which may have a glancing blow at Earth.

Geomagnetism

The geomagnetic conditions over the past 24 hours were quiet to active. Quiet to unsettled conditions are expected over the next 24 hours with remaining minor chances of isolated active and minor storm periods during next days due to influence of the HSS and possible glancing blow from the CME.

Proton flux levels

The greater than 10 MeV proton was at the nominal levels in the past 24 hours. The proton flux is expected to remain below 10 pfu threshold over the next day, with a small chance that a particle event occurs in association with an X-class flare or a coronal mass ejection.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux was below the 1000 pfu threshold and is expected to remain below this threshold for the next days.The 24h electron fluence was at normal level. The electron fluence is expected to be at normal levels in the next days.

Today's estimated international sunspot number (ISN): 135, based on 17 stations.

Solar indices for 20 May 2023

Wolf number Catania	///
10cm solar flux	170
AK Chambon La Forêt	031
AK Wingst	035
Estimated Ap	037
Estimated international sunspot number	139 - Based on 22 stations

Noticeable events summary

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

All times in UTC

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