:Issued: 2024 Apr 26 1250 UTC :Product: documentation at http://www.sidc.be/products/tot #--------------------------------------------------------------------# # DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC # #--------------------------------------------------------------------# SIDC URSIGRAM 40426 SIDC SOLAR BULLETIN 26 Apr 2024, 1250UT 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) PREDICTIONS FOR 26 Apr 2024 10CM FLUX: 165 / AP: 023 PREDICTIONS FOR 27 Apr 2024 10CM FLUX: 163 / AP: 014 PREDICTIONS FOR 28 Apr 2024 10CM FLUX: 161 / AP: 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 GEO: 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 ISN : 137, BASED ON 12 STATIONS. 99999 SOLAR INDICES FOR 25 Apr 2024 WOLF NUMBER CATANIA : /// 10CM SOLAR FLUX : 167 AK CHAMBON LA FORET : 006 AK WINGST : 002 ESTIMATED AP : 002 ESTIMATED ISN : 215, BASED ON 17 STATIONS. NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES 25 1311 1321 1327 ////// M1.0 59/3638 V/3III/1 25 1703 1712 1716 ////// M1.3 59/3638 III/2 END UMAGF 30503 40426 1004/ 25062 1/006 20001 31112 UMAGF 31523 40426 0000/ 25008 1/002 20001 31112 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 # #--------------------------------------------------------------------#