:Issued: 2026 Jan 21 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 60121 SIDC SOLAR BULLETIN 21 Jan 2026, 1230UT SIDC FORECAST SOLAR FLARES : M-class flares expected (probability >=50%) GEOMAGNETISM : Moderate (ISES: Major) magstorm expected (A>=50 or K=6) SOLAR PROTONS : Proton event in progress (>10 MeV) PREDICTIONS FOR 21 Jan 2026 10CM FLUX: 182 / AP: 039 PREDICTIONS FOR 22 Jan 2026 10CM FLUX: 182 / AP: 019 PREDICTIONS FOR 23 Jan 2026 10CM FLUX: 182 / AP: 007 Solar Active Regions and flaring: Solar flaring activity was moderate over the past 24 hours, with two M-class flares observed. A total of 12 numbered sunspot groups were identified on the disk. The largest event was an M3.4 flare (SIDC Flare 6701) peaking on January 21 at 07:12 UTC, produced by SIDC Sunspot Group 769 (NOAA Active Region 4349). An additional M1.1 flare (SIDC Flare 6699) peaking on January 21 at 01:35 UTC was produced by SIDC Sunspot Group 766 (NOAA Active Region 4345). SIDC Sunspot Group 762 (NOAA Active Region 4342), currently located at N14W04, maintained a Beta-Gamma magnetic configuration over the past 24 hours. SIDC Sunspot Group 766 (NOAA Active Region 4345), currently located at S17W02, also maintained a Beta- Gamma magnetic configuration over the past 24 hours. Solar flaring activity is expected to remain moderate over the next 24 hours, with C-class flares expected and M-class flares likely. Coronal mass ejections: No Earth-directed coronal mass ejection (CME) were observed in SOHO/LASCO images over the past 24 hours. Coronal holes: SIDC Coronal Hole 146 (trans-equatorial coronal hole with a positive polarity) first reached the central meridian on January 16 and is now partially positioned on the western side of the Sun. Solar wind: Over the past 24 hours, Earth remained under the influence of the interplanetary CME (ICME) associated with the full-halo CME observed in SOHO/LASCO C2 on 2026 Jan 18 at 18:12 UTC (linked to the X1.9 flare, SIDC Flare 6678, peaking at 18:09 UTC from SIDC Sunspot Group 740, NOAA AR 4341, and accompanied by Type II radio emission). Solar wind speed stayed elevated but showed a slow decline, ranging from about 1014 km/s down to about 650-700 km/s. The interplanetary magnetic field (IMF) also weakened compared to the initial impact, with total IMF, Bt, varying up to about 22 nT, while North-South component of the IMF, Bz, remained predominantly southward, ranging from about -18 nT to +3 nT. Continued disturbed solar wind conditions are expected while the ICME tail and trailing structures pass, with a gradual return toward slower background solar wind once the ICME influence fades. Geomagnetism: Sustained high solar wind speed combined with long intervals of southward interplanetary magnetic field (IMF), Bz, maintained storm conditions for much of the past 24 hours. Globally, NOAA Kp remained mostly at major storm levels (around Kp 7), with severe storm intervals reaching Kp 8- during the 09:00 to 12:00 UTC and 21:00 to 24:00 UTC periods on January 20. Locally over Belgium, K_BEL stayed mainly in the active to moderate storm range (K_BEL 5 to 6), reaching 6 during 10:00 to 12:00 UTC and again from about 19:00 UTC until around 03:00 UTC, then gradually easing toward active levels later in the period. Further moderate storm intervals remain possible if Bz turns more strongly southward again, but a slow recovery is expected as the ICME weakens. Proton flux levels: The solar energetic particle event associated with the X1.9 flare (SIDC Flare 6678, peaking on 2026 Jan 18 at 18:09 UTC) is still ongoing. The greater than 10 MeV GOES proton flux has been above the 10 pfu threshold since 2026 Jan 18 at 22:50 UTC and remains above it. The greater than 10 MeV flux is currently decaying toward the threshold and is expected to decrease further, likely dropping below the threshold within the next 24 hours. A new solar energetic particle event cannot be excluded given the number of sunspot groups currently on the visible disk, in particular the most magnetically complex regions. Electron fluxes at GEO: The greater than 2 MeV GOES electron flux stayed close to the 1000 pfu alert threshold over the past 24 hours and showed a renewed increase toward the end of the interval, intermittently exceeding the threshold. With solar wind speeds still elevated and geomagnetic conditions gradually moving into a recovery phase, the greater than 2 MeV electron flux may remain near or above the threshold during the next 24 hours. The 24-hour electron fluence remained at moderate levels and is expected to stay around these levels, with a possible increase if elevated electron flux persists. TODAY'S ESTIMATED ISN : 164, BASED ON 07 STATIONS. SOLAR INDICES FOR 20 Jan 2026 WOLF NUMBER CATANIA : /// 10CM SOLAR FLUX : 178 AK CHAMBON LA FORET : 146 AK WINGST : 120 ESTIMATED AP : 132 ESTIMATED ISN : 172, BASED ON 18 STATIONS. NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES 21 0115 0135 0158 S16W05 M1.1 SF ///4345 21 0653 0712 0722 S18E62 M3.4 1B ///4349 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 # #--------------------------------------------------------------------#