:Issued: 2024 Apr 25 1248 UTC :Product: documentation at http://www.sidc.be/products/meu #--------------------------------------------------------------------# # DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC # # (RWC Belgium) # #--------------------------------------------------------------------# SIDC URSIGRAM 40425 SIDC SOLAR BULLETIN 25 Apr 2024, 1247UT SIDC FORECAST SOLAR FLARES : M-class flares expected (probability >=50%) GEOMAGNETISM : Active conditions expected (A>=20 or K=4) SOLAR PROTONS : Warning condition (activity levels expected to increase, but no numeric forecast given) PREDICTIONS FOR 25 Apr 2024 10CM FLUX: 204 / AP: 007 PREDICTIONS FOR 26 Apr 2024 10CM FLUX: 204 / AP: 013 PREDICTIONS FOR 27 Apr 2024 10CM FLUX: 204 / AP: 011 Solar Active Regions and flaring: Solar flaring activity remained at high levels in the past 24 hours with multiple low M-class flares. There are 16 numbered and several unnumbered active regions on the visible solar disc. NOAA AR 3645 (beta-gamma) remains the largest region, while NOAA AR 3643 (beta-gamma-delta) and NOAA AR 3648 (beta-gamma-delta) became the most complex ones. NOAA AR 3639 (beta), NOAA AR 3646 (beta) and NOAA AR 3647 (beta) have decreased the complexity of their underlying magnetic field. The strongest activity was M2.0 flare, start time 22:54 UTC, end time 23:05 UTC, peak time 22:59 UTC on April 24th produced by NOAA AR 3637 (beta) from the west limb. The remaining M-class flaring was produced by NOAA AR 3645 and NOAA AR 3648. The solar flaring activity is expected to be at moderate to high levels over the next days with likely further M-class flaring and 25% chance for isolated X-class flaring. Coronal mass ejections: No Earth-directed coronal mass ejections (CMEs) have been observed in coronagraph imagery over the past 24 hours. Type II and type IV radio bursts were reported related to C9.4-class flaring from NOAA AR 3638 14:10 UTC on April 24th. The resulting westward CME is estimated to have no impact on Earth. Coronal holes: A positive polarity mid-latitude coronal hole is currently residing 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 background slow solar wind regime. The solar wind velocity was predominantly below 400 km/s. The interplanetary magnetic field (B) was weak with a maximum value of 4.8 nT and a minimum Bz of -3.9 nT. The B field phi angle was alternating between the negative and the positive sector (directed towards and away from the Sun). The solar wind conditions might experience mild enhancements on April 25th - April 28th with possible mild high speed streams encounters related to several positive polarity coronal holes. Geomagnetism: The geomagnetic conditions over the past 24 hours were quiet. Quiet to active conditions are anticipated for April 25th with chances for isolated minor storm levels on April26th -April 28th. 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 GEO: The greater than 2 MeV electron flux as measure by GOES 16 and GOES 18 has exceeded the1000 pfu threshold over the past 24h and is expected to repeatedly exceed 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 moderate levels for the upcoming days. TODAY'S ESTIMATED ISN : 220, BASED ON 11 STATIONS. SOLAR INDICES FOR 24 Apr 2024 WOLF NUMBER CATANIA : /// 10CM SOLAR FLUX : 199 AK CHAMBON LA FORET : 004 AK WINGST : 002 ESTIMATED AP : 142 ESTIMATED ISN : 261, BASED ON 20 STATIONS. NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES 24 1207 1214 1239 ////// M1.4 60/3645 24 2227 2250 2254 ////// M1.1 73/3657 III/1VI/1 24 2254 2259 2305 ////// M2.0 59/3638 25 0140 0149 0201 ////// M1.0 60/3645 END BT #--------------------------------------------------------------------# # Solar Influences Data analysis Center - RWC Belgium # # Royal Observatory of Belgium # # # # Website http://www.sidc.be. # # E-mail sidc-support@oma.be # # To unsubscribe http://www.sidc.be/registration/unsub.php # # # # Legal notices: # # - Intellectual Property Rights: # # http://www.astro.oma.be/common/internet/en/data-policy-en.pdf # # - Liability Disclaimer: # # http://www.astro.oma.be/common/internet/en/disclaimer-en.pdf # # - Use and processing of your personal information: # # http://www.astro.oma.be/common/internet/en/privacy-policy-en.pdf # #--------------------------------------------------------------------#