SIDC Ursigram

:Issued: 2024 Apr 28 1241 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 40428
SIDC SOLAR BULLETIN 28 Apr 2024, 1240UT
SIDC FORECAST 
SOLAR FLARES  : M-class flares expected (probability >=50%)
GEOMAGNETISM  : Active conditions expected (A>=20 or K=4)
SOLAR PROTONS : Quiet
PREDICTIONS FOR 28 Apr 2024  10CM FLUX: 152 / AP: 013
PREDICTIONS FOR 29 Apr 2024  10CM FLUX: 150 / AP: 011
PREDICTIONS FOR 30 Apr 2024  10CM FLUX: 148 / AP: 014

Solar Active Regions and flaring: Solar flaring activity was at moderate
levels over the past 24 hours with two M-class flares. There are 9 numbered
active regions on the visible solar disc with NOAA AR 3654 (beta-gamma)
being by far the largest and the most complex, solely responsible for the
moderate flaring. The strongest activity was a M3.0 flare, start time 21:29
UTC, end time 21:49 UTC, peak time 21:40 UTC on April 27th. The solar
flaring activity is expected to be at low to moderate levels over the next
days with possible isolated M-class flaring from NOAA AR 3654.

Coronal mass ejections: A very faint and slow coronal mass ejection (CME)
was observed by LASCO/C2 to lift off the solar disc to the south-west after
11:00 UTC on April 27th. The CME might be related to earlier C2.6 flaring
(peak time 09:05 UTC on April 27th) from NOAA 3654. This CME is very faint,
not clearly visible in STEREO A coronagraph data and is not expected to
produce significant impact on Earth. Should any of the plasma arrive,
possibly on May 1st, it will probably be mixed with high speed streams on
its way. No other Earth-directed CMEs have been observed in the available
coronagraph imagery over the past 24 hours.

Coronal holes: A long negative polarity coronal hole stretching from high
northern latitudes down to the equator continues to reside on the central
meridian. The high speed stream emanating from it might arrive to Earth on
May 1st.

Solar wind: Over the past 24 hours the solar wind parameters (ACE and
DSCOVR) remained enhanced, possibly under the mixed influence of a glancing
blow ICME arrival and high speed stream (HSS) from a positive polarity
coronal hole. The solar wind velocity was predominantly in the range of 400
to 500 km/s. The interplanetary magnetic field (B) had a maximum value of
12.8 nT with a minimum Bz of -9.6 nT. The B field phi angle was
predominantly in the positive sector (directed away from the Sun). The
solar wind conditions are expected to remain mildly elevated throughout
April 28th with possible new mild high speed stream arrivals on April 28th
and May 1st.

Geomagnetism: The geomagnetic conditions over the past 24 hours were at
quiet to active. Mostly quiet to active conditions are expected for April
27th - April 30th with remaining small chances for isolated minor storms.

Proton flux levels: Over the past 24 hours the greater than 10 MeV GOES
proton flux was at background levels and is expected to remain so over the
next days.


Electron fluxes at GEO: The greater than 2 MeV electron flux as measured by
GOES 16 and GOES 18 was below the1000 pfu threshold over the past 24 hours
and is expected to remain so in the upcoming days. The 24h electron fluence
was at nominal levels and is expected to remain so in the upcoming days.


TODAY'S ESTIMATED ISN  : 139, BASED ON 08 STATIONS.

SOLAR INDICES FOR 27 Apr 2024
WOLF NUMBER CATANIA    : ///
10CM SOLAR FLUX        : 153
AK CHAMBON LA FORET    : 021
AK WINGST              : 014
ESTIMATED AP           : 014
ESTIMATED ISN          : 148, BASED ON 18 STATIONS.

NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM Catania/NOAA RADIO_BURST_TYPES 
27  1223  1235 1244 S07W15 M2.1 SN       74/3654      CTM/1 
27  2129  2140 2149 ////// M3.0          74/3654      III/2 
END

BT
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