SIDC Ursigram

:Issued: 2025 Apr 27 1231 UTC
:Product: documentation at http://www.sidc.be/products/meu
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# DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC     #
# (RWC Belgium)                                                      #
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SIDC URSIGRAM 50427
SIDC SOLAR BULLETIN 27 Apr 2025, 1230UT
SIDC FORECAST 
SOLAR FLARES  : C-class flares expected, (probability >=50%)
GEOMAGNETISM  : Active conditions expected (A>=20 or K=4)
SOLAR PROTONS : Quiet
PREDICTIONS FOR 27 Apr 2025  10CM FLUX: 156 / AP: 016
PREDICTIONS FOR 28 Apr 2025  10CM FLUX: 154 / AP: 013
PREDICTIONS FOR 29 Apr 2025  10CM FLUX: 152 / AP: 007

Solar Active Regions and flaring: Solar flaring activity was low over the
past 24 hours, only minor C-class flaring was observed. A total of 15
numbered sunspot groups were identified on the disk over the past 24 hours,
all with simple alpha or beta magnetic field configuration, and most of
them are decaying. The largest flare was a C1.3 one from SIDC Sunspot Group
468 currently located at S15E87, with beta magnetic field confuration.
Solar flaring activity is expected to be low over the next 24 hours, with
C-class flares expected.

Coronal mass ejections: A wide CME erupted towards the north, first seen at
18:00 UTC on 26 April on LASCO C2, but is is not expected to arrive to the
Earth. No Earth-directed CMEs were observed in the available coronagraph
imagery in the last 24 hours.

Coronal holes: There is a large positive polarity coronal hole (SIDC
Coronal Hole 104) in the southern hemisphere, although parts of it have
rotated out of view over the west limb. In the northern hemisphere, there
is one smaller, positive polarity coronal hole, that crossed the central
meridian on 24 April. On the eastern part of the Sun, there is a recurrent
transequatorial elongated negative polarity coronal hole, SIDC Coronal Hole
99.

Solar wind: The solar wind speed has been gradually decreasing to around
400 km/s in the last 24 hours, with an interplanetary magnetic field of
5-10 nT, and Bz mostly positive.  In the next 24 hours we may see the
arrival of a high speed stream if the solar wind from the positive polarity
coronal holes in the southern and/or in the northern hemisphere arrive to
the Earth.


Geomagnetism: Geomagnetic conditions have been quiet globally and locally
(Kp and K_Bel up to 2). The possible arrival of a high speed solar wind
stream may increase conditions to active levels. Otherwise, mostly quiet
conditions can be expected.

Proton flux levels: The greater than 10 MeV proton flux was below the
threshold level over the past 24 hours. It is expected to remain below the
threshold level over the next 24 hours.

Electron fluxes at GEO: The greater than 2 MeV electron flux measured by
GOES 18 and 19has been at, or slightly below, the threshold over the past
24 hours. The greater than 2 MeV electron flux may increase over the next
24 hours.The 24-hour electron fluence is presently between normal and
moderate levels, it may increase over the next 24 hours.





Zdroj : SIDC Ursigram





Předpověď sluneční aktivity pro období : April 25 - May 01, 2025

Zdroj : http://www.asu.cas.cz/~sunwatch




Poslední fotografie ze SOHO / SDO:



Různé barvy snímků prozrazují odlišné vlnové délky - každá
vlnová délka je vyzařována plynem o určité teplotě: oranžová: 80 000 °C,
modrá: 1 000 000 °C, zelená: 1 500 000 °C, hnědá: 2 500 000 °C.

  

    




      He II/Si XI 30,4 nm

      80 000 °C

      EIT 304

    
    





      Fe IX/X 17,1 nm

      1 000 000 °C

      EIT 171

    
    





      Fe XII 19,5 nm

      1 500 000 °C

      EIT 195

    
    





      Fe XV 28,4 nm

      2 500 000 °C

      EIT 284

    
  
  

    




SDO/HMI Continuum


    





SDO/HMI Magnetogram


    





LASCO C2


    




LASCO C3

  










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