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

2021/04/12

       Weekly Bulletin on Solar and Geomagnetic Activity
                  Highlights on 05 - 11.04.2021,
                   Forecast on 12 - 19.04.2021,
    Carrington Rotation 2242, 2243 (14,23.04; 11,47.05.2021)   
             Earth out of ecliptic (-6.6 - -6.2) deg. 
             (S35 - N25 is zone of geoeffectiveness)

 THE SUNSPOT-FORMING SOLAR ACTIVITY REMAINED ON VERY LOW LEVEL.
THE SUNSPOT OBSERVED 5-6.04 (41 SPOTLESS DAYS AT 2021). ESTIMA-
TED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUMBER IN 
THE INTERNATIONAL SYSTEM (old) FOR PERIOD  W=2+5/-2 (Wn=4+7/-4).
THERE ARE ONE SMALL SUNSPOT GROUP ON NOTHERN HEMISPHERE HAVE BE-
EN OBSERWED. 

 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=020+10/-10. 

FLARE ACTIVITY  WAS AT LOW LEVEL. 18 SOLAR FLARE OF X-RAY CLASS 
"A" AND 6 CORONAL MASS EJECTIONS (8, 10-11.04) WAS 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     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  -    S05L151 S30L172 S35L146 S30L144 ~2%   05.04 1 -  SOHO,SDO...
* - 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 11.04/0210 UT THE EARTH IS IN THE "-" SECTOR OF THE INTERPLA-
NETARY MAGNETIC FIELD. THE FOLLOWING SECTOR BOUNDARY "-/+" IT CAN BE 
EXPECT 20.04.

---------------------------------------------------------------------- 
MARCH    05     06     07     08     09     10     11   
Wus     011    011    000    000    000    000    000
F10.7   072    074    076    074    076    078    073    
bcg  <A1.0  <A1.0  <A1.0   1.1  <A1.0   A1.0   A1.6   GOES
Sp      005    000    000    000    000    000    000   msh   
N                                                      
IMF      +      +      +      +      +      +     -/+   DSCOVR   
>2  3.2E+6 1.9+6 1.6E+6 1.5E+6 1.6E+6 1.4+6 1.4E+6   GOES
Ie>2    398    212    157    132    165    141    136   pfu 
Ap       3      3      17     3      3      5      6    n  
Dst                                                     n KIOTO
Amsc     3      3      18     4      2      5      6    n 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 NO 
OBSERVED. 
 
NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS 
ORBIT IS NOT EXPECTED.

GEOMAGNETIC CONDITION ALL THE PERIOD REMAINED QUIET AND UNSETTLED 
EXCEPT 7.04 WHEN ON THE CENTER DATA IN BOULDER WAS OBSERVED 9h G1
-SUBSTORM. ON THE DATA ISMIRAN IT WAS A G1-SUBSTORM WITH A DURATI-
ON OF 6h. THE MAGNETIC DISTURBANCE WAS CAUSED BY THE EARTH's PAS-
SAGE OF INTERACTING WEAK HIGH-VELOCITY STREAMS FROM A CONGLOMERATE 
OF SMALL CORONAL HOLES WITH WEAK MAGNETIC FIELDS.

IN THE NEXT WEEK THE MOST PROBABLE IS EXPECTED A QUITE AND UNSET-
TLED 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