Viewing archive of Saturday, 29 April 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Apr 29 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
29 Apr 2023	159	018
30 Apr 2023	155	013
01 May 2023	150	008

Bulletin

Solar flaring activity was low but frequent during the last 24 hours. Around 20 C-class flares were detected, with the brightest being a C7 yesterday at 22:10 UT from NOAA Active Region (AR) 3288 (magnetic configuration Beta-Gamma-Delta, Catania group 67). The same AR also produced most of the flaring together with another member of the same group of AR, NOAA 3285 (magnetic configuration Beta, Catania group 65). NOAA AR 3285 and 3288 are now in the process of merging together and C-class flare activity from those two AR is very likely, while M-class activity is still possible for the next 24 hours.

A partial halo Coronal Mass Ejection (CME) launched today at 01:36 UT can be seen in LASCO/C2 images. Although relatively narrow, it has a chance to become geo-effective either late 1 May or early 2 May. Another CME, launched today at 03:53 and seen in LASCO/C2 images, was ejected from the NE limb and is not expected to be geo-effective.

The greater than 10 MeV proton flux was at nominal levels over the past 24 hours and is expected to remain so for the next 24 hours. The greater than 2 MeV electron flux was above the 1000 pfu threshold for the majority of the time during the last 24 hours and is expected to remain above the 1000 pfu threshold for most, if not all of the next 24 hours. The 24-hour electron fluence was at moderate levels during the last 24 hours and is expected to continue at this level for the next 24 hours.

The Solar Wind (SW) conditions are affected by the arrival of a High Speed Stream (HSS) yesterday, as previously predicted. The SW speed increased further from around 650 km/s to 750 km/s. The total magnetic field (Bt) remained low and varied between 1 and 6 nT, while Its North-South (Bz) component was mostly negative and ranged between -5 and -5 nT during the last 24 hours. The interplanetary magnetic field phi angle was predominantly directed towards the Sun over the last 24 hours. The fast SW conditions are expected to continue in the next 24 hours.

Geomagnetic conditions were globally moderate to active (NOAA Kp 3 to 4) and locally quiet to active (K BEL 2 to 4), during the last 24 hours. For the next 24 hours they are expected to remain moderate to active with quiet short periods, both globally and locally.

Today's estimated international sunspot number (ISN): 103, based on 10 stations.

Solar indices for 28 Apr 2023

Wolf number Catania	129
10cm solar flux	150
AK Chambon La Forêt	///
AK Wingst	022
Estimated Ap	020
Estimated international sunspot number	110 - Based on 18 stations

Noticeable events summary

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

All times in UTC

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