SIDC Weekly Bulletin
Review of past solar and geomagnetic activity.| Source | SIDC (RWC-Belgium) |
| Frequency | Weekly |
| Format | Plain text |
| Mail header | SIDC Weekly Bulletin |
| SIDC code | bul |
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:Issued: 2026 Jul 15 1430 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# WEEK 1332 from 2026 Jul 06 Solar Active Regions (ARs) and flares --------------- The solar flaring activity was at very low to high levels over the past week. There were 12 numbered active regions on the visible solar disk throughout the week which produced more than 30 C-class flares and 8 M-class flares. The largest flare was a M5.3 flare (SIDC Flare 8155) peaking on Jul 05 at 17:57 UTC, which was produced by SIDC Sunspot Group 860 (NOAA Active Regions 4479). During the flare, the source region (SIDC Sunspot Group 860) of the flare had beta-gamma-delta configuration of its photospheric magnetic field. SIDC Sunspot Groups 909 and 910 (NOAA Active Region 4485 and 4482) were the magnetically complex regions which produced almost all flaring activities. Coronal mass ejections --------------------- A wide coronal mass ejections (CME) was first observed in SOHO/LASCO-C2 images around 22:12 on Jul 07. It was associated to a filament eruption on NE quadrant of the Sun. This CME had a projected speed of about 800 km/s and a projected width of about 115 deg. A glancing blow associated to this CME was expected at Earth on Jul 11 but it did not arrive at Earth. A second CME was first observed in STEREO-A/COR2 images around 07:53 UTC on Jul 09. It was associated to a C2.7 flare (S13 W27, SIDC flare 8178) produced by SIDC Sunspot Group 909 (NOAA Active Region 4485) on Jul 09 (peak time 07:13). This CME had a projected speed of about 750 km/s and a projected width of about 60 deg. A glancing blow associated to this CME was expected at Earth on Jul 12 but it did not arrive at Earth. Coronal Holes --------------------- Four coronal holes (CH) crossed the central meridian over the past week. SIDC CH 170, spanning 10 S - 25 N (negative polarity), crossed the central meridion during Jul 06-07. SIDC CH 171, spanning 30 S - 20 S (very small, negative polarity) crossed the central meridian during July 08-09. SIDC CH 162 (recurrent, mid-latitude extension of polar-north coronal hole with a negative polarity) crossed the central meridian on Jul 10-13, but the probability of a associated high-speed stream arrival at Earth was considered low due to its location. SIDC CH 172, spanning 9 S - 3 N (very small, positive polarity) crossed the central meridian during July 11-12. Proton flux levels --------------------- The greater than 10 MeV GOES proton flux was at nominal levels throughout the entire week. Electron fluxes at GEO --------------------- Over the past week, the greater than 2 MeV electron flux, as measured by GOES-18 and GOES-19 satellites, remained almost always above the 1000 pfu threshold level except on July 08-09. Solar wind --------------------- Earth was within the slow solar wind regime until Jul 09 with a speed of around 450 km/s and the interplanetary magnetic field was upto 10 nT. On Jul 09, Earth came under the influence of high speed streams (HSSs) from the SIDC Coronal Hole (CH) 170 (equatorial and negative polarity) that crossed the central meridian during Jul 06-07. The solar wind speed increased upto 680 km/s, the interplanetary magnetic field (IMF) increased upto 13 nT, and Bz component decreased to -9 nT. On Jul 11, the solar wind speed started to decrease and it increased again, due to the arrival of HSSs either from the SIDC CH 171 (very small, negative polarity) that crossed the central meridian during Jul 06-07 or from another SIDC CH 171 (very small, negative polarity) that crossed the central meridian during July 08-09. The solar wind speed increased upto 595 km/s, the interplanetary magnetic field (IMF) increased upto 9 nT, and Bz component decreased to -7 nT. The solar wind parameters transitioned from fast to slow solar wind regime at the end of the week. Geomagnetism --------------------- Geomagnetic conditions were mostly quiet to unsettled (NOAA Kp and K BEL 1 to 3) until Jul 09. It reached active levels (K=4) during few intervals on July 09 and 10, due to the arrival of high speed streams (HSSs) from the SIDC Coronal Hole (CH) 170 (equatorial and negative polarity) that crossed the central meridian during Jul 06-07. On Jul 12, 12:00-03:00 UTC, geomagnetic conditions reached minor storm levels at the planetary level (NOAA Kp=5) and upto active levels (K BEL=4) locally. It was due to the further arrival of HSSs either from the SIDC CH 171 (very small, negative polarity) that crossed the central meridian during Jul 06-07 or from another SIDC CH 171 (very small, negative polarity) that crossed the central meridian during July 08-09. Geomagnetic conditions were at quiet to unsettled levels (Kp and K_BEL 2 to 3) at the end of the past week. --------------------------------------------------------------------------- DAILY INDICES DATE RC EISN 10CM Ak BKG M X 2026 Jul 06 071 071 125 010 C2.5 0 0 2026 Jul 07 076 059 110 005 B9.3 1 0 2026 Jul 08 109 085 116 016 B5.8 1 0 2026 Jul 09 103 082 110 020 B4.1 1 0 2026 Jul 10 127 080 107 013 B4.3 0 0 2026 Jul 11 /// 076 112 009 B4.6 0 0 2026 Jul 12 /// 070 107 024 B5.4 1 0 --------------------------------------------------------------------------- # RC : Sunspot index (Wolf Number) from Catania Observatory (Italy) # EISN : Estimated International Sunspot Number # 10cm : 10.7 cm radioflux (DRAO, Canada) # Ak : Ak Index Wingst (Germany) # BKG : Background GOES X-ray level (NOAA, USA) # M,X : Number of X-ray flares in M and X class, see below (NOAA, USA) --------------------------------------------------------------------------- NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES 07 1409 1419 1422 S11E53 M4.0 1B 70/4482 II/1IV/1 08 1749 1756 1801 S11E37 M1.5 1N 70/4482 09 0217 0227 0229 S08E29 M1.1 SF 70/4482 12 0717 0811 0842 S09W70 M1.1 S 69/4485 #--------------------------------------------------------------------# # 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 # #--------------------------------------------------------------------#
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This report is sent once a week, typically on a monday.The weekly bulletin gives an overview of solar and geomagnetic activity of the past week and includes a noticeable solar events list.
Check the ISES code book for information on ISES codes.