Dear users, as announced by the NOAA and NASA 25 solar cycle forecast commission on September 15, 2020 (https://www.weather.gov/news/201509-solar-cycle, cycle 24 minimum occurred in December 2019 (W*=1.1, and in the new system W*=1.8). In my opinion, this can finally be judged only in December 2020, since if spotless days continue for another full two months or more (which has already happened in the history of reliable observations of sunspots), the value of the relative number of sunspots will fall below the announced level. Therefore, for two more months I will consider the current solar cycle SC24. V. Ishkov ------------------------------------------------------------------- THE RELATIVE MONTHLY MEAN SUNSPOT NUMBER ON SEPTEMBER 2020 HAS MADE Wsep. = 0.4 0.7(n) THAT GIVES FOR 134 MONTH (2020, MARCH) OF DEVELOPMENT CURRENT 24 SO- LAR CYCLE THE SMOOTHED MONTHLY MEAN SUNSPOT NUMBER W*mar. = 1.8 3.0 - × ÎÏ×ÏÊ ÓÉÓÔÅÍÅ W*feb. = 1.7 2.8 - × ÎÏ×ÏÊ ÓÉÓÔÅÍÅ On July 1, 2015 Centre in Brussels moved to a new system of calcu- lation the relative number of sunspots and practically all of the values were replaced throughout the numbered series of Wolf numbers (see link). While there is addictive, I recalculated (0.6) to the old system, but only W*, and present below the new values for the minimum and maximum of 24 cycles SA. THE BEGINNING OF 24 SOLAR CYCLE - I 2009 with W*=1.8; (2.2) THE TIME OF THE CURRENT CYCLE MAXIMUM - IV 2014, - Wmax =82; (116.4) THE END OF 24 SOLAR CYCLE (THE POINT OF MINIMUM) - I - VI 2020; XII 2019 - Possible. The observed magnetic structures corresponding SC 25 (>43 on October 2019) can be seen http://www.solen.info/solar/cycle25_spots.html Provisional daily International Sunspot Numbers for July 2020 (70 obser- vatories): 1.. 0 6.. 0 11.. 0 16.. 0 21.. 0 26.. 0 2.. 0 7.. 0 12.. 0 17.. 0 22.. 0 27.. 0 3.. 0 8.. 0 13.. 0 18.. 0 23.. 8M 28.. 0 4.. 0 9.. 0 14.. 2 19.. 0 24.. 6 29.. 0 5.. 0 10.. 0 15.. 0 20.. 0 25.. 5 30.. 0 Minimum : 0 on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 21, 22, 26, 27, 28, 29, 30 [The daily value W in old system close to true (in a minimum phase) can be received, multiplying by k = 0.6]. THE MONTHLY MEAN OF OBSERVED RADIO FLUX OF THE 10 cm (2800 MHz) ON SEPTEMBER 2020, AND SMOOTHES ON 2020, MARCH F10.7sep. = 70.7 F*10.7mar.= 70.19 LET PASSING DATA: F*10.7feb.=69.8; F*10.7jan.=69.5; F*10.7dec.=69.4; F*10.7nov.=69.4; F*10.7oct.=69.6; F*10.7sep.=69.8; F*10.7aug.=69.8; F*10.7jul.=69.8; THE MONTHLY MEAN OF GEOMAGNETIC Ap-index ON JULY 2020, AND SMOOT- HES ON 2020, JANUARY Ap sep. = 5.7 Ap*mar. = xxx --------------------------------------------------------------------- Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 28.09 - 04.10.2020, Forecast on 05 - 11.10.2020, Carrington Rotation 2235, 2236(07,74.09; 05,01.10.2020) Earth out of ecliptic (7.1 - 6.5) deg. (S20 - N35 is zone of geoeffectiveness) THE SUNSPOT-FORMING SOLAR ACTIVITY REMAINED ON VERY LOW LEVEL THE VISIBLE SOLAR DISK WAS SPOTLESS (199 SPOTLESS DAYS AT 2020). ESTIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUM- BER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD W=0 (Wn=0). NEXT WEEK THE LEVEL OF SUNSPOT ACTIVITY WAS ON VERY LOW LEVEL. VISIBLE SOLAR DISK WITH HIGH PROBABILITY WILL BE SPOTLESS. LI- KELY WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR NEXT WEEK IS W=010+10/-10. FLARE ACTIVITY WAS AT VERY LOW LEVEL. SEVEN SOLAR FLARE OF LOW X-RAY CLASS "A" HAVE BEEN OBSERVED. ------------------------------------------------------------------- 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 -------------------------------------------------------------------- NEXT WEEK THE FLARE ACTIVITY IS EXPECTED AT 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 CH + Pn N25E10L119 N10W10L099 N20E20L089 18.2% 28.09 3 A ACE... óH - N33W15L015 N30W05L025 N27W12L018 N30W22L008 0.6% 1 ACE... * - 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. ---------------------------------------------------------------------- FROM 22.09/09 UT, THE EARTH IS IN THE "+" SECTOR OF THE INTERPLANE- TARY MAGNETIC FIELD. THE FOLLOWING THE NEXT SECTOR BOUNDARY "+/-" IT CAN EXPECT 6.10. ---------------------------------------------------------------------- SEPTEMBER 28 29 30 01 02 03 04 OCTOBER Wus 000 000 013 000 000 000 000 F10.7 074 073 073 073 072 072 071 èbcg A2.4 A2.7 A3.3 A4.1 A3.8 A3.7 A3.9 GOES Sp 000 000 010 000 010 000 000 msh N IMF + + + + + + + DSCOVR Å>2 2.7E+8 5.2å+8 1.1E+9 1.3E+9 1.5E+9 1.1E+9 1.4å+9 GOES Ie>2 15792 13675 29293 32431 38685 23377 26522 pfu Ap 33 11 15 11 9 5 4 nô Dst nô KIOTO Amsc 31 14 15 11 10 5 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 ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT HAVE BEGUN AT 24.09/1540 UT AND OBSERVED AT 28.09-4.10. NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS OR- BIT IS EXPECTED 5-12.10. A MODERATE MAGNETIC STORM (G2, Amsc= 40 nT, dur.= 33 h.) BY DATA OF BOULDER CENTRE AND MINOR MAGNETIC STORM (G1, Amsc=38 nT, dur.=12 h.) AND SUBSTORM (G1, dur.=9 h.)ACCORDING OF IZMIRAN DATA REGISTRED AT 27-29.09. THESE DISTURBANCES OF THE GEOMAGNETIC FIELD WERE CAUSED BY HIGH-VELOCITY STREAM OF SOLAR WIND FROM THE LOW LAW-LATITUDE PART OF THE NORTHERN POLAR CORONAL HOLE "+" POLARITY. IN OTHER DAYS THE GEO- MAGNETIC CONDITION REMAINED QUIET. NEXT WEEK THE MOST PROBABLY QUIET AND UNSETTLED GEOMAGNETIC CONDI- TION WILL BE OBSERVED . 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