:Issued: 2023 Sep 28 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 30928 SIDC SOLAR BULLETIN 28 Sep 2023, 1230UT SIDC FORECAST SOLAR FLARES : C-class flares expected, (probability >=50%) GEOMAGNETISM : Quiet (A<20 and K<4) SOLAR PROTONS : Quiet PREDICTIONS FOR 28 Sep 2023 10CM FLUX: 152 / AP: 010 PREDICTIONS FOR 29 Sep 2023 10CM FLUX: 150 / AP: 013 PREDICTIONS FOR 30 Sep 2023 10CM FLUX: 150 / AP: 011 Solar Active Regions and flaring: Solar flaring activity over the past 24 hours was at moderate levels. The largest flare was a M1.3-flare, with peak time 09:07 UTC on September 28. This flare was associated with NOAA AR 3450, which rotated over the eastern limb and has been the most active region in the last 24 hours. There are currently 7 numbered active regions on the visible disk. NOAA AR 3445 (beta) has decayed and NOAA AR 3449 (beta-gamma) has grown in size, all other regions have simple alpha or beta magnetic field configurations. The solar flaring activity is likely to be at low levels over the coming days with C-class flares expected, M-class flares possible and a low chance for isolated X-class flaring. Coronal mass ejections: No Earth directed CME’s have been detected in the last 24 hours. A CME was seen erupting towards the north-east in LASCO-C2 data from 11:12 UTC on September 27 this is determined to be back-sided and is not expected to impact the Earth. Coronal holes: A positive polarity coronal hole began passing the central meridian on September 27 in the northern hemisphere. Solar wind: In the last 24 hours, the interplanetary magnetic field fluctuated between 2 nT and 6 nT and the Bz fluctuated between positive and negative values going down to – 5 nT. The solar wind speed had values varied between 360 km/s and 535 km/s. The phi-angle was mainly in the positive sector (directed away from the Sun). Slow solar wind conditions are expected in the next 24 hours with a possibility of a slight enhancement on the 28 September due to a filament eruption on September 25. Geomagnetism: The geomagnetic conditions over the past 24 hours were unsettled globally (Kp 3) and locally (K Bel 3). Quiet to unsettled conditions are expected in the next 24 hours. Proton flux levels: The greater than 10 MeV proton flux was at background level over the last 24 hours and is expected to remain so in the next 24 hours. Electron fluxes at GEO: The greater than 2 MeV electron flux measured by GOES-16 went above the 1000 pfu threshold value between 12:00 UTC and 17:50 UTC on September 27. The greater than 2 MeV electron flux is expected to increase above the threshold again in the next 24 hours. The 24h electron fluence became elevated going towards moderate levels and is expected to remain at moderate levels in the next 24 hours. TODAY'S ESTIMATED ISN : 121, BASED ON 15 STATIONS. SOLAR INDICES FOR 27 Sep 2023 WOLF NUMBER CATANIA : 168 10CM SOLAR FLUX : 156 AK CHAMBON LA FORET : 019 AK WINGST : 016 ESTIMATED AP : 016 ESTIMATED ISN : 142, BASED ON 25 STATIONS. NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES 28 0858 0907 0911 S18E65 M1.2 SF 84/3450 V/3 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 # #--------------------------------------------------------------------#