Viewing archive of Thursday, 29 April 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Apr 29 1234 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
29 Apr 2021	078	006
30 Apr 2021	077	014
01 May 2021	076	031

Bulletin

X-ray flux has remained below C level throughout the period. All three regions on disc remained stable or in decay. Both Catania groups 91 and 92 (NOAA regions 2821 and 2820) decreased in size. X-ray flux is likely to remain below C level though an isolated C-flare is still possible.

No new Earth directed CMEs have been detected in coronagraph data.

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 just touched the 1000 pfu event threshold. The 24h electron fluence was at normal levels but rising. As Solar wind enhancements have dyed out, the electron fluence is expected to remain at normal levels during next days.

Earth is within a slow Solar wind regime. Solar wind speed is stable at around 320km/s since midnight while total magnetic field was under 5nT with an unremarkable Bz component and a phi angle indicating magnetic field orientation towards the Sun. By end of tomorrow April 30, start of May 1 we may see Solar wind perturbations due to a combination of enhanced speed associated to the positive polarity coronal hole that transited the central meridian in the past days, and magnetic field perturbations due to passing magnetic clouds from first the April 25 CME and later the April 26 CME. Though likelihood and confidence for the CME arrivals is low.

Geomagnetic conditions were quiet (local K Dourbes and NOAA Kp 0-2). Geomagnetic conditions are expected to be quiet to unsettled and then possibly increasing late tomorrow to active conditions with also minor storm levels possible if any of the CME arrivals show up.

Today's estimated international sunspot number (ISN): 037, based on 09 stations.

Solar indices for 28 Apr 2021

Wolf number Catania	050
10cm solar flux	078
AK Chambon La Forêt	006
AK Wingst	002
Estimated Ap	002
Estimated international sunspot number	043 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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