Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 10 - 16.05.2021, Forecast on 17 - 24.05.2021, Carrington Rotation 2243, 2244 (11,47.05; 7.69.06.2021) Earth out of ecliptic (-4.0 - -3.6) deg. (S38 - N30 is zone of geoeffectiveness) THE SUNSPOT-FORMING SOLAR ACTIVITY REMAINED ON LOW LEVEL. ES- TIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUM- BER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD W = 16+6/-9 (Wn=26+10/-15). TWO SMALL AND QUITE SUNSPOT GROUP WAS OBSERVED ON THE SOLAR VISIBLE DISK. NEXT WEEK SUNSPOT ACTIVITY WILL BE ON VERY LOW LEVEL. WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNATI- ONAL SYSTEM (old) FOR NEXT WEEK IS W=010+20/-10. FLARE ACTIVITY WAS AT LOW LEVELS. ONE SOLAR FLARE OF X-RAY "C" CLASS, 27 - "B" AND 4 CORONAL MASS EJECTIONS (10, 13, 16.05) 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 DSF to te localization l deg. Fl AR CME/to 13.05 1600 N18W00L320 15 ÷1 12822 CME/1924 -------------------------------------------------------------------- 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 12.05/0750 UT THE EARTH IS IN THE "-" SECTOR OF THE INTERPLA- NETARY MAGNETIC FIELD. THE FOLLOWING SECTOR BOUNDARY "-/+" IT CAN BE EXPECT 27.05. ---------------------------------------------------------------------- MAY 10 11 12 13 14 15 16 MAY Wus 036 031 031 024 024 024 011 F10.7 077 076 075 075 071 073 073 èbcg á5.2 á4.6 á3.6 á3.2 á2.7 á2.5 A4.1 GOES Sp 170 070 230 110 070 060 050 msh N 1 IMF + +/- - - - - - DSCOVR Å>2 5.3å+6 2.2E+6 2.3å+8 1.5E+6 2.2E+6 1.8E+6 1.9å+6 GOES Ie>2 619 220 771 128 197 192 197 pfu Ap 6 3 41 7 4 8 5 nô Dst nô KIOTO Amsc 9 3 28 8 5 7 4 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 NO OBSERVED. NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT IS NOT EXPECTED. MAJOR MAGNETIC STORM (G3, Ams=82, dur.=12 h) ACCORDING TO THE CEN- TER IN BOULDER DATA AND MODERATE MAGNETIC STORM (G2, Ams=40, dur.= 15 h) ACCORDING TO IZMIRAN DATA WAS OBSERVED ON 12.09 AS A CONSE- QUENCE DISTURBANCES FROM SOLAR FILAMENT EJECTION IN THE CENTRAL PART OF THE VISIBLE SOLAR DISC. ARRIVAL OF INTERPLANETARY SHOCK WA- VE (SC) IS MARKED 12/0643 UT. OTHER DAYS THE GEOMAGNETIC CONDITION REMAINED QUIET AND UNSETTLED. IN THE NEXT WEEK THE MOST PROBABLE IS EXPECTED A QUITE AND UNSET- TLED GEOMAGNETIC CONDITION. IT IS POSSIBLE TO INCREASE GEOMAGNETIC DISTURBANCES ON 17-18.05 DUE TO THE SLIDING IMPACT OF DISTURBANCE FROM FILAMENT EJECTION AT 13.05, BUT THE PROBABILITY OF A MINOR MAGNETIC STORM IS NOT MORE THAN 20%. 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