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Solar Activity Forecast

2017/04/24

      Weekly Bulletin on Solar and Geomagnetic Activity
                 Highlights on 17 - 23.04.2017,
                 Forecast on 24 - 30.04.2017,
   Carrington Rotations 2189, 2190 (02,37.04; 29,63.04.2017)
           Earth above the ecliptic (-5.4, -5,0) deg. 
               (S30-N28 is geoeffectiveness zone)

 SUNSPOT-FORMING ACTIVITY WAS ON A VERY LOW LEVEL TO 19.04 (17.04 day 
was spotless-30th in this year), 20 AND 22- AT LOW, 21, 23- AT MIDDLE. 
THE ESTIMATED,  MOST LIKELY  WEEKLY AVERAGE VALUE OF THE RELATIVE SUN-
SPOT NUMBER IN THE INTERNATIONAL SYSTEM  (old) FOR THE THE PERIOD  IS 
W=14+12/-14 (Wn=22+19/-22). ON THE VISIBLE DISC OF THE SUN 0- 3 SMALL 
QUITE SUNSPOT GROUP. 

 NEXT WEEK SUNSPOT-FORMING ACTIVITY  IS EXPECTED  AT THE LOW AND VERY 
LOW LEVELS. THE ESTIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE RE-
LATIVE SUNSPOT NUMBER  IN THE INTERNATIONAL SYSTEM (old) FOR THE NEXT 
WEEK IS W=30+20/-20.

 FLARE ACTIVITY WAS AT THE LOW LEVEL AT 17-18.04 AND VERY LOW IN OTHER 
DAYS. 12 SOLAR FILAMENT EJECTION OCCURRENCES THROUGH THE PERIOD. ACCOR-
DING TO THE SOHO AND STEREO CORONOGRAPHS DATA > 18 CMEs,  ONE OF WHICH 
WAS TYPE II  (angular with 144 deg.) HAVE BEEN OBSERVED.
----------------------------------------------------------------------
FLARES to   tm    te   local.     Class   E(1-8A)  AR   RII/IV   CME
                                 X-ray/p  J/m-2
DSF     to     te      l  . Fl     A        CME/to
19.04 >0114  >1300   S59E39L101    16                 /1820
20.04 >0101  >1315   N43E25L101     8 
20.04 >0943  >2313   N27E34L092    11
20.04 >1644  >0604   N23E23L103     6 
20.04  2026   2123   N19E18L108    12 
20.04 <2200          N14E77L072     ?    C5.5  12651 CME/2200
21.04 >0108  >1255   S46W16L128     5 
21.04 >0850  >2317   S57E18L194     7 
21.04 >1413  >0702   N19E35L064    11                    
22.10 >1657  >0511   N24E26L073     6 
23.10  0416 0520 0536 N12E39L046    10            12652 CME/0600
23.04  1658   1734   N32E00L085     10 
----------------------------------------------------------------------

NEXT WEEK FLARE ACTIVITY IS EXPECTED AT A LOW AND VERY 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   Space Obser.
CH  +  S15L225 S22L223  S30L221 S20L225       17.04   7  G1  SDO, SOHO..
CH  +  N12L185 S20L175  S23L173 S18L190 12200 19.04   7  G1  SDO, SOHO..
CH  -  N20L111 S10L093  S15L107 S05L124 66200 24.04   7  G2  SDO, SOHO..
CH  -  S16L102 S20L077  S38L092 S20L107 66200 25.04   7  G1  SDO, SOHO..
CH  -  S30L067 S38L065  S60L053 S35L082 25000 28.04   7  G0  SDO, SOHO..
Last 3 CH is family by south polar CH "-" polarity;
Sch - CH Square in Mm**2 (in square megameters) near the central meri-
dian on http://sdowww.lmsal.com/suntoday/; n/d - no data;
R - solar rotations; EE-date of possible geomag. disturbance in the 
Earth's environment. G(0-5)-geoeffectivity in last solar rotation on
the middle latitudes. A-active geomagnetic condition.
------------------------------------------------------------------------

 FROM 17.04/05 to 21/1538 UT  THE EARTH IS IN "+" SECTOR OF THE INTER-
PLANETARY MAGNETIC FIELD. THE FOLLOWING SECTOR BOUNDARY +/-  THE EARTH 
HAS EXPECTED TO PASS 15.05.

APRIL    17     18     19     20     21     22     23     APRIL
Wus     000    012    014    026    039    029    043 
F10.7   075    080    081    081    082    084    083 
bcg   1.1   9.7   1.3   1.1   1.1   1.0   9.9     GOES
Sp      000    020    110    140    180    240    260  msh   
N        1                    1      21                
IMF      +      +      +      +     +/-     -      -      DSCOVR   
>2  6.7+7 4.4+7 2.0E+7 1.5E+7 5.1+7 9.9+7 1.0+8     GOES
Ie>2   1717   1129    501    546   2805   7466  20544  pfu 
Ap       2      5      16     33     19     58     42  n BOULDER 
Dst     -11    -7     -42    -55    -44    -62    -59  n KIOTO 
Amsc     3      17     15      23     19    35     31  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 GOES15 in (electrons/cm2.s.sr) for events
> 1000 pfu.

THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT WAS BE-
GINING AT 09.04/1330 UT AND OBSERVED 9-19.04. NEXT ENHANCE WAS BEGI-
NING 21.04/1425 UT AND OBSERVED AT 21-23.04.

THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSTATIONARY ORBIT OF VERY 
HIGH LEVEL IS EXPECTED 24 - 30.04.

 GEOMAGNETIC CONDITION WAS UNSETTLED TILL 19.04.  THE MAJOR MAGNETIC 
STORM (G2, Ams=51, dur.= 12 h.)  WAS OBSERVED SINCE THE BEGINNING OF
OF DAY 20.04  ACCORDING TO THE CENTER IN BOULDER DATA.  ACCORDING TO 
THE IZMIRAN DATA  IT WAS THE MINOR MAGNETIC STORM  (G1, Ams= 28, dur. 
= 27 h.) WHICH HAS BEGUN 19.04/20 UT. THIS GEOMAGNETIC DISTURBATION 
IS CAUSED BY ARRIVAL OF INTERPLANETARY CME FROM SOLAR FILAMENT EJEC-
TION 18.04 WHEN THE EARTH ALREADY ENTERED IN THE SOLAR WIND HIGH-SPE-
ED STREAM FROM TRANS-EQUATORIAL CORONAL HOLE "+" POLARITY. THE FOLLO-
WING MAGNETIC STORM (G2, Ams= 37, dur.= 33 h.)  ACCORDING TO IZMIRAN 
DATA (MINOR)  AND (G2, Ams ~51, dur. >60 h.) ACCORDING TO THE CENTER 
IN BOULDER (MAJOR) HAVE BEGUN IN THE SECOND HALF 21.04. THIS GEOMAGNE-
TIC DISTURBATION PROBABLY BECAME RESULT OF ICME ARRIVAL FROM DSF  19.
04,  BUT CONDITIONS OF HIS EMERGENCE  AND DEVELOPMENT  AREN'T  CLEAR  
TO ME YET.

NEXT WEEK GEOMAGNETIC CONDITION WILL BE ACTIVE, FROM TIME TO TIME IN-
CREASING UP TO THE MINOR MAGNETIC STORM  LEVEL 24 - 27.04- THE RECUR-
RENT INCREASE CONNECTED WITH PASSING BY THE EARTH SOLAR WIND OF HIGH-
SPEED STREAMS  FROM FAMILY OF CORONAL HOLES OF POLAR CH OF THE SOUT-
HERN HEMISPHERE.  IN OTHER DAYS  GEOMAGNETIC CONDITION WILL BE QUIET 
AND UNSETTLED.

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