Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation
Russian Academy of Sciences
( founded in 1939 )
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Solar Activity Forecast

2021/10/25

                   25 CYCLE OF SOLAR ACTIVITY, 
             THE BRANCH OF RISE: THE PHASE OF MINIMUM      

       Weekly Bulletin on Solar and Geomagnetic Activity
                  Highlights on 19 - 24.10.2021,
                   Forecast on 25 - 31.10.2021 
   Carrington Rotations 2249, 2250 (24,59.09; 21,88.10.2021)   
              Earth out of ecliptic (-1.5 - -1.9) deg. 
              (S30 - N30 is zone of geoeffectiveness)

THE SUNSPOT-FORMING SOLAR ACTIVITY WAS ON VERY LOW AND LOW LE-
VELS. 18.10 THE SUN WAS SPOTLESS (2021 total: 60 days - 21%).  
ESTIMATED MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUM-
BER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD IS W=12+16/-5 
(Wn= 20+26/-9). THERE WERE THREE SUNSPOT GROUPS ON VISIBLE SO-
LAR DISK: ONE MIDDLE SIZE AND 2 - SMALL, ALL ON S-HEMISPHERES 
HAS BEEN OBSERVED.

 NEXT WEEK SUNSPOT ACTIVITY  WILL BE ON LOW AND MIDDLE LEVELS. 
WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE IN-
TERNATIONAL SYSTEM (old) FOR NEXT WEEK IS W=040+20/-20. 

 FLARE ACTIVITY WAS AT LOW AND VERY LOW LEVELS. 50 FLARES OF X-
RAY CLASS "B", ONE SOLAR FILAMENT EJECTIONS AND 17 CORONAL MASS 
EJECTIONS (18, 19, 21-23.10) HAVE BEEN OBSERVED. 
-------------------------------------------------------------------
FLARES >M1 X-RAY CLASSES
       to   tm   te     local.   Class  E(1-8A) AR   RII/IV   CME
                                X-ray/p J/m-2 
DSF (EPL) to      te   localization l deg.  Fl    AR    CME/to
21.10  0536     0625    N24W43L       7
--------------------------------------------------------------------

NEXT WEEK THE FLARE ACTIVITY IS EXPECTED AT VERY LOW AND LOW LEVELS.

ON THE VISIBLE SOLAR DISK THE FOLLOWING CORONAL HOLES WERE OBSERVED:
---------------------------------------------------------------------
   sign  N end   E end   S end   W end   Sch  EE    R G  Spacecraft 
* - 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. 
----------------------------------------------------------------------

20.10/14 UT THE EARTH IS IN THE "-" SECTOR OF THE INTERPLANETARY MAG-
NETIC FIELD. FOLLOWING SECTOR BOUNDARY "-/+" IT CAN BE EXPECT 25.10.
----------------------------------------------------------------------- 
OCTOBER   18     19     20     21     22     23     24  OCTOBER
Wus      000    011    011    011    028    032    046 
F10.7    077    076    076    082    087    087    093
bcg    4.0   2.6   4.2   1.3   1.7   1.9   2.3  GOES
Sp       170    185    130    100    250    540    570  msh   
N         1                           1             1 
IMF       +     +/-     -      -      -      -      -   DSCOVR   
>2   4.6E+6 1.9E+6 1.6E+6 1.2E+6 1.5+6 1.7E+6 1.4E+6  GOES
Ie>2     432    198    155    144    154    140    151  pfu
Ap        10     14     6      6      4      3      4   n  
Dst                                                     n KIOTO
Amsc      8      17     5      6      4      3      4   IZMIRAN 
------------------------------------------------------------------------            
>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 NOT
OBSERVED.

 NEXT WEEK  THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS 
ORBIT IS CAN NOT EXPECTED.

THE GEOMAGNENIC CONDITION REMAIND QUITE AND UNSETTLED ALL DAYS EX-
CEPT 19.10, WHEN THE 6-hour SUBSTORM INTENCITY G1 WAS OBSERVED AC-
CORDING IZMIRAN DATA. ACCORDING TO THE CENTER IN BOULDER DATA THIS
SUBSTORM INTENCITY WAS G0. THIS GEOMAGNETIC DISTURBANCE WAS ASSOCI-
ATED WITH THE PASSAGE OF SOLAR WIND HIGH-SPEED STREAM FROM WEAK CO-
RONAL HOLE OF THE S-HEMISPHERE.

 THE NEXT WEEK MOST PROBABLE QUIET AND UNSETTLED GEOMAGNETIC CONDI-
TION.

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