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Daily bulletin on solar and geomagnetic activity from the SIDC

Випущено: 2023 Apr 28 1231 UTC

SIDC Forecast

Сонячні спалахи

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

Geomagnetism

Quiet (A<20 and K<4)

Сонячні протони

Quiet

	10cm flux	Ap
28 Apr 2023	140	015
29 Apr 2023	138	011
30 Apr 2023	136	005

Bulletin

Solar flaring activity was low but frequent during the last 24 hours. Many C-class flares were detected, with the brightest being a C6 today at 01:22 from NOAA Active Region (AR) 3285 (magnetic configuration Beta, Catania group 65). The most flare-producing AR was NOAA 3288 (magnetic type Beta-Gamma-Delta, Catania group 67) with seven and NOAA 3285 with six C-class flares during the last 24 hours. NOAA AR 3285 and 3288 are expected to continue producing numerous C-class flares, while NOAA AR 3288 is capable of producing M-class flares in the next 24 hours.

A partial halo Coronal Mass Ejections (CME) can be seen in LASCO/C2 images starting from yesterday 01:25 UT and has a change to become geo-effective. If so it is estimated to arrive at 29 Apr. A partial halo CME automatically detected by CACTus at Apr 26 23:34 UT is a back-sided event.

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 yesterday between 12:15-23:40 UT and for very short intervals from then on until today 04:50 UT. The 24-hour electron fluence was at moderate levels during the last 24 hours. In the next 24 hours hours the greater than 2 MeV electron flux is expected to follow a similar pattern, of several hours above the 1000 pfu threshold. The 24-hour electron fluence is expected to remain at moderate levels for the next 24 hours.

A negative polarity corona hole crossed the central meridian during the last 24 hours. However, because of its location high up in the northern hemisphere it is not expected to cause an impact on Earth's environment.

The Solar Wind (SW) conditions are still affected by the High Speed Stream (HSS) that arrived at 28 Apr. The SW speed remained between 550 km/s and 700 km/s. The total magnetic field (Bt) continue its gradual drop as it decreased from 8 nT to below 5 nT, while Its North-South (Bz) component fluctuated between -7 and 6 nT during the last 24 hours. The interplanetary magnetic field phi angle was predominantly directed towards the Sun over the last 24 hours, although since today 5:30 UT it shows signs of variation in direction. The effect of the HSS on the SW conditions is expected to slowly wane in the next 24 hours, yet the SW speed will most probably remain high.

Geomagnetic conditions were globally and locally active to moderate (NOAA Kp 4+ to 3- and K BEL 3-4) during the last 24 hours. They are expected to become moderate to quiet in the next 24 hours.

Today's estimated international sunspot number (ISN): 113, based on 08 stations.

Solar indices for 27 Apr 2023

Wolf number Catania	142
10cm solar flux	141
AK Chambon La Forêt	///
AK Wingst	021
Estimated Ap	022
Estimated international sunspot number	120 - Based on 21 stations

Noticeable events summary

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

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