Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 24 - 30.05.2021, Forecast on 31.04 - 07.05.2021, Carrington Rotation 2244, 2245 (11,48.05; 07,69.06.2021) Earth out of ecliptic (-3.0 - -2.5) deg. (S32 - N32 is zone of geoeffectiveness) THE SUNSPOT-FORMING SOLAR ACTIVITY REMAINED ON LOW LEVEL. THE ESTIMATED MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUM- BER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD IS W=18+4/-2 (Wn=30+6/-4). ON THE VISIBLE SOLAR DISK 4 SMALL SUNSPOT GROUPS WERE OBSERVED. NEXT WEEK SUNSPOT ACTIVITY WILL BE ON VERY LOW AND LOW LEVEL. WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE IN- TERNATIONAL SYSTEM (old) FOR NEXT WEEK IS W=020+10/-10. FLARE ACTIVITY WAS AT LOW LEVELS. 17 SOLAR FLARE OF X-RAY "C" CLASS, 86 - "B" AND 13 CORONAL MASS EJECTIONS (24, 25, 27-30. 05) WAS OBSERVED AT THE PERIOD. ------------------------------------------------------------------- FLARES >M1 X-RAY CLASSES to tm te local. Class E(1-8A) AR RII/IV CME X-ray/Ïp J/m-2 28.05 2219 0012 2313 N19W68L194 C9.4/SF 12824 II/1 CME/2312 (2087km/s) pH DSF to te localization l deg. Fl AR CME/to -------------------------------------------------------------------- NEXT WEEK THE FLARE ACTIVITY IS EXPECTED AT LOW AND VERY LOW LEVEL. ON THE VISIBLE SOLAR DISK THE FOLLOWING CORONAL HOLES WERE OBSERVED: --------------------------------------------------------------------- sign N end E end S end W end Sch EE R G Sp/craft * - low geoeffectivity, the substorms with duration <6 h. only. Sch - CH area in % solar hemisphere near the central meridian on https://www.solarmonitor.org/; n/d - no data; R - solar rotations; EE-date of possible geomagnetic disturbance in the Earth's environment. G(0-5)-geoeffectivity in last solar rotation on the middle latitudes. A-active geomagnetic condition. ---------------------------------------------------------------------- AFTER 26.05/0300 UT THE EARTH IS IN THE "+" SECTOR OF THE INTERPLA- NETARY MAGNETIC FIELD. THE FOLLOWING SECTOR BOUNDARY "+/-" IT CAN BE EXPECT 09.06. ---------------------------------------------------------------------- MAY 24 25 26 27 28 29 30 íáê Wus 029 036 034 034 028 026 027 F10.7 073 084 088 083 077 076 074 èbcg á7.0 á8.4 ÷2.9 ÷2.4 ÷1.3 ÷2.1 B1.2 GOES Sp 190 140 490 530 530 130 070 msh N 1 1 1 IMF - - - - - - - DSCOVR Å>2 5.5å+7 7.1E+7 2.9å+7 1.8E+6 1.7E+6 2.3E+6 2.1å+6 GOES Ie>2 1262 1531 1150 - 178 134 350 pfu Ap 4 3 13 16 3 7 6 nô Dst nô KIOTO Amsc 3 4 11 9 2 9 6 nô IZMIRAN ---------------------------------------------------------------------- Å>2 - Daily Electron Fluency e/(cm2-ster-day) with E>2 MeV. Ie>2 - the maximum intensity of electron flux in geostationary or- bits in days according to GOES-15 in (electrons/cm2.s.sr) for events > 1000 pfu. THE GREATER THAN 2 MeV RECURRENT ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT BEGUN AT 24/1805 UT AND WAS OBSERVED 24-26.05 ONLY. NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT IS NOT EXPECTED. AFTER SOLAR FLARE OF CLASS ó9.4/1F AT MAY, 20 IN ENVIRONMENT SPA- CE WAS REGISTERED SOLAR PROTON EVENT WITH INTENSITY "S1": Pr (E>10 íÜ÷) TO-29/0015, max 15pfu-29/0320, Te~29/2330 UT; THE GEOMAGNETIC CONDITION REMAINED QUIET AND UNSETTLED, EX- CEPT 26-27.05, WHEN ACCORDING TO THE CENTER IN BULDER DATA AF- TER A SUDDEN IMPULSE (SI-26/1252) THE MINOR MAGNETIC STORM (G1, Ams = 30, dur.= 15 h), BUT ACCORDING IZMIRAN DATA IT WAS A SUB- STORM (9 h)OF INTENSITY G1. THIS GEOMAGNETIC DISTURBANCE WAS A CONSEQUENCE OF THE FLASH OF FLARE ACTIVITY AT 22.05 WHEN A SE- RIES OF SMALL FLARES WAS ACCOMPANIED BY CORONAL MASS EJECTION. IN THE NEXT WEEK THE MOST PROBABLE IS EXPECTED A QUITE AND UN- SETTLED GEOMAGNETIC CONDITION. HIGHLIGHT AND FORECAST COMPOSED FROM DATA: NOAA SWPC, BOULDER, USA http://www.swpc.noaa.gov, THE SOLAR INFLUENCES DATA ANALYSIS CENTRE, SIDC, BRUSSELS, BELGIUM http://sidc.oma.be/index.php3, THE IZMIRAN, MOSCOW, TROITSK, RUSSIA http://www.izmiran.ru V. Ishkov