Viewing archive of Thursday, 18 May 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 May 18 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
18 May 2023	142	004
19 May 2023	144	006
20 May 2023	146	018

Solar Active Regions and flaring

Solar flaring activity was at moderate levels over the past 24 hours with three M-class flares and several C-class flares being detected. The largest flares of the period were a M2.2 flare, peaking at 11:47 UTC on May 18, a M1.2 flare, peaking at 06:55 UTC on May 18 and a M1.0 flare, peaking at 06:26 UTC on May 18. associated with ARs behind the east limb (N18E88). The region produced the majority of the flaring activity. NOAA AR 3305 (beta-gamma class) remains the largest and most complex active region, but produced only low C-class flare in the last 24 hours. Low flaring activity was also produced by NOAA ARs 3309 (beta class) and 3310 (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 small chance of X-class flare.

Coronal mass ejections

In the past 24 hours, multiple coronal mass ejections (CME) and flows were observed in the available SOHO/LASCO coronagraph imagery and automatically detected by the Cactus tool over. In particular, the CME was observed in SOHO/LASCO-C2 at around 16:36 UTC on May 17. The CME was associated with the C4.3 flare (peaking at 15:30 UTC) from NOAA AR 3309. The bulk of the CME is directed to the southwest and is likely to be a near miss. However, a full analysis is still ongoing, and more details will be provided later. No other Earth-directed CMEs have been detected in the available coronagraph imagery.

Solar wind

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) indicated a return to a near slow solar wind regime. The solar wind speed values ranged between 410 km/s and 440 km/s. The interplanetary magnetic field magnitude was about 4 nT. The southward component of the interplanetary magnetic field fluctuated between -3 nT and 3 nT. Slow solar wind conditions are expected to prevail until May 20. On May 20, a weak enhancement is possible as a high-speed stream associated with two small equatorial coronal holes that crossed the central meridian yesterday may arrive.

Geomagnetism

During last 24 hours the geomagnetic conditions were at quiet levels (NOAA KP 1-2 and Local K Dourbes 1-2). Geomagnetic conditions are expected to be quiet during next days. Active conditions may be possible from May 20 associated to HSS arrival.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was slightly elevated, remaining well below radiation storm levels. The proton flux is expected to remain below 10 pfu threshold over the next day, with a very 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): 112, based on 15 stations.

Solar indices for 17 May 2023

Wolf number Catania	122
10cm solar flux	138
AK Chambon La Forêt	006
AK Wingst	004
Estimated Ap	005
Estimated international sunspot number	101 - 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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