Viewing archive of Friday, 26 April 2024

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2024 Apr 26 1251 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

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

	10cm flux	Ap
26 Apr 2024	165	023
27 Apr 2024	163	014
28 Apr 2024	161	015

Solar Active Regions and flaring

Solar flaring activity was at moderate levels over the past 24 hours with only two low M-class flares. There remain 16 numbered active regions on the visible solar disc. NOAA AR 3645 (beta) is now rotating behind the west limb. NOAA AR 3643 (beta-gamma) and NOAA AR 3648 (beta-gamma) have decreased their complexity, while NOAA AR 3654 (beta-gamma) has exhibited growth and increased its magnetic complexity. The strongest activity was an impulsive M1.4 flare, start time 17:03 UTC, end time 17:16 UTC, peak time 17:12 UTC on April 25th produced by NOAA AR 3638 (beta) from behind the west limb. The solar flaring activity is expected to be at low to moderate levels over the next days with likely M-class flaring and decreasing chances for isolated X-class flaring.

Coronal mass ejections

No Earth-directed coronal mass ejections (CMEs) have been observed in the available coronagraph imagery over the past 24 hours.

Coronal holes

A positive polarity mid-latitude coronal hole continues to reside on the central meridian in the southern hemisphere. The high speed stream emanating from it might arrive to Earth on April 28th, possibly superimposed with expected preceding high speed stream arrival.

Solar wind

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) were indicative of a mild transient arrival. This could be a glancing blow from the ICME related to the M3.4 flaring produced by NOAA AR 3638 on April 21st. The solar wind velocity was slow varying between 281 km/s and 387 km/s. The interplanetary magnetic field (B) was mildly enhanced reaching a maximum value of 10.2 nT and a minimum Bz of -9.3 nT. The B field phi angle was predominantly in the negative sector (directed towards the Sun). The solar wind conditions are expected to continue to experience mild enhancements throughout April 26th - April 27th with a possible further mild glancing blow arrival late on April 27th. Enhanced solar wind conditions are expected to continue on April 28th - April 29th with expected mild high speed streams encounters from several positive polarity coronal holes.

Geomagnetism

The geomagnetic conditions over the past 24 hours were quiet to unsettled. Predominantly quiet to active conditions are anticipated for April 26th - April 28th with possible isolated minor storm levels.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was at background levels and is expected to continue so over the next days, pending any fast eruptive solar activity.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux as measure by GOES 16 and GOES 18 has briefly exceeded the 1000 pfu threshold over the past 24h and has currently returned back to low values, well below the1000 pfu threshold. The greater than 2 MeV electron flux as measure by GOES 16 and GOES 18 is expected to remain below the 1000 pfu threshold in the upcoming days. The 24h electron fluence was at boundary of nominal to moderate level and is expected to be at nominal levels during the upcoming days.

Today's estimated international sunspot number (ISN): 137, based on 12 stations.

Solar indices for 25 Apr 2024

Wolf number Catania	///
10cm solar flux	167
AK Chambon La Forêt	006
AK Wingst	002
Estimated Ap	002
Estimated international sunspot number	215 - Based on 17 stations

Noticeable events summary

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

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