:Issued: 2024 Apr 19 1231 UTC :Product: documentation at http://www.sidc.be/products/meu #--------------------------------------------------------------------# # DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC # # (RWC Belgium) # #--------------------------------------------------------------------# SIDC URSIGRAM 40419 SIDC SOLAR BULLETIN 19 Apr 2024, 1230UT SIDC FORECAST SOLAR FLARES : M-class flares expected (probability >=50%) GEOMAGNETISM : Active conditions expected (A>=20 or K=4) SOLAR PROTONS : Quiet PREDICTIONS FOR 19 Apr 2024 10CM FLUX: 220 / AP: 022 PREDICTIONS FOR 20 Apr 2024 10CM FLUX: 216 / AP: 024 PREDICTIONS FOR 21 Apr 2024 10CM FLUX: 210 / AP: 022 Solar Active Regions and flaring: Solar flaring activity was at moderate level, with multiple C-class flares and three M-class flares recorded in the past 24 hours. The largest flare of the period was an M2.1 flare, peaking at 04:53 UTC on Apr 19, associated with NOAA AR 3647 (beta-delta class). This region was the main driver of the flaring activity observed over the past 24 hours together with NOAA AR 3645 (beta class). Low flaring activity was also produced by NOAA AR 3635 (beta class) and NOAA AR 3639 (beta-gamma class). Other regions on the disc have simple configuration of their photospheric magnetic field (alpha and beta) and did not show any significant flaring activity. The solar flaring activity is expected to be at moderate levels over the next 24 hours, with M-class flares possible and a chance for X-class flare. Coronal mass ejections: Multiple CMEs, directed towards south-east from the Earth's perspective, were observed in SOHO/LASCO-C2 starting from approximately 17:16 on Apr 17, likely related to the flaring activity from NOAA AR 3638 and 3643. While bulk of the CME is off the Sun-Earth line, a glancing blow from these CMEs could be possible on Apr 21 - 22, although with low confidence. Solar wind: At the beginning of the period, the solar wind parameters were reflecting return to slow solar wind conditions. The solar wind speed decreased from the values about 360 km/s to 310 km/s; the total interplanetary magnetic field was below 5 nT. The solar wind conditions became slightly disturbed from around 04:12 UTC on April 19, with the total interplanetary magnetic field reaching the values up to 16 nT. The southward component of the interplanetary magnetic field fluctuated between -12 nT and 5 nT. This is probably associated with the arrival of a faint partial halo CME observed on Apr 15. The solar wind conditions are expected to remain slightly elevated due to the ICME passage with a chance of a further weak enhancement late on Apr 20 - Apr 21 due to the arrival of a high-speed stream from a negative polarity coronal hole, that started to cross the central meridian on Apr 17 and a possible ICMEs arrival. Geomagnetism: The geomagnetic conditions over the past 24 hours were quiet to active globally (NOAA-Kp=1-4). Locally only quiet to unsettled(K-Bel=2-3) conditions were observed over Belgium. Mostly unsettled to active geomagnetic conditions are expected for the next 24 hours, with a chance of reaching minor storm levels due to ongoing ICME influence and expected HSS arrival. Proton flux levels: Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to remain so with possible enhancements in case of increased levels of solar activity over the next days. Electron fluxes at GEO: The greater than 2 MeV electron flux, as measured by the GOES-16 satellite, remained below the 1000 pfu threshold. It is expected to remain below the threshold during the next 24 hours. The 24 hour electron fluence was at normal levels and is expected to remain at these levels for the following 24 hours. TODAY'S ESTIMATED ISN : 245, BASED ON 11 STATIONS. SOLAR INDICES FOR 18 Apr 2024 WOLF NUMBER CATANIA : 225 10CM SOLAR FLUX : 227 AK CHAMBON LA FORET : 009 AK WINGST : 004 ESTIMATED AP : 004 ESTIMATED ISN : 214, BASED ON 23 STATIONS. NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES 18 1922 2001 2012 S12E17 M1.6 SF 60/3645 III/1 18 2012 2016 2021 S12E17 M1.6 SF ///3647 III/1 19 0440 0453 0503 N20W58 M2.1 SF 60/3647 VI/1III/1 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 # #--------------------------------------------------------------------#