SIDC Ursigram

:Issued: 2024 Apr 26 1251 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 40426
SIDC SOLAR BULLETIN 26 Apr 2024, 1250UT
SIDC FORECAST 
SOLAR FLARES  : M-class flares expected (probability >=50%)
GEOMAGNETISM  : Minor storm expected (A>=30 or K=5)
SOLAR PROTONS : Warning condition (activity levels expected to increase,
but no numeric forecast given)
PREDICTIONS FOR 26 Apr 2024  10CM FLUX: 165 / AP: 023
PREDICTIONS FOR 27 Apr 2024  10CM FLUX: 163 / AP: 014
PREDICTIONS FOR 28 Apr 2024  10CM FLUX: 161 / AP: 015

Solar Active Regions and flaring: Solar flaring activity was at moderate
levels over the past 24 hours with only two low M-class flares. There
remain 16 numbered active regions on the visible solar disc. NOAA AR 3645
(beta) is now rotating behind the west limb. NOAA AR 3643 (beta-gamma) and
NOAA AR 3648 (beta-gamma) have decreased their complexity, while NOAA AR
3654 (beta-gamma) has exhibited growth and increased its magnetic
complexity. The strongest activity was an impulsive M1.4 flare, start time
17:03 UTC, end time 17:16 UTC, peak time 17:12 UTC on April 25th produced
by NOAA AR 3638 (beta) from behind the west limb. The solar flaring
activity is expected to be at low to moderate levels over the next days
with likely M-class flaring and decreasing chances for isolated X-class
flaring.

Coronal mass ejections: No Earth-directed coronal mass ejections (CMEs)
have been observed in the available coronagraph imagery over the past 24
hours.

Coronal holes: A positive polarity mid-latitude coronal hole continues to
reside on the central meridian in the southern hemisphere. The high speed
stream emanating from it might arrive to Earth on April 28th, possibly
superimposed with expected preceding high speed stream arrival.

Solar wind: Over the past 24 hours the solar wind parameters (ACE and
DSCOVR) were indicative of a mild transient arrival. This could be a
glancing blow from the ICME related to the M3.4 flaring produced by NOAA AR
3638 on April 21st. The solar wind velocity was slow varying between 281
km/s and 387 km/s. The interplanetary magnetic field (B) was mildly
enhanced reaching a maximum value of 10.2 nT and a minimum Bz of -9.3 nT.
The B field phi angle was predominantly in the negative sector (directed
towards the Sun). The solar wind conditions are expected to continue to
experience mild enhancements throughout April 26th - April 27th with a
possible further mild glancing blow arrival late on April 27th. Enhanced
solar wind conditions are expected to continue on April 28th - April 29th
with expected mild high speed streams encounters from several positive
polarity coronal holes.

Geomagnetism: The geomagnetic conditions over the past 24 hours were quiet
to unsettled. Predominantly quiet to active conditions are anticipated for
April 26th - April 28th with possible isolated minor storm levels.

Proton flux levels: Over the past 24 hours the greater than 10 MeV GOES
proton flux was at background levels and is expected to continue so over
the next days, pending any fast eruptive solar activity.

Electron fluxes at GEO: The greater than 2 MeV electron flux as measure by
GOES 16 and GOES 18 has briefly exceeded the 1000 pfu threshold over the
past 24h and has currently returned back to low values, well below the1000
pfu threshold. The greater than 2 MeV electron flux as measure by GOES 16
and GOES 18 is expected to remain below the 1000 pfu threshold in the
upcoming days. The 24h electron fluence was at boundary of nominal to
moderate level and is expected to be at nominal levels during the upcoming
days.


TODAY'S ESTIMATED ISN  : 137, BASED ON 12 STATIONS.

SOLAR INDICES FOR 25 Apr 2024
WOLF NUMBER CATANIA    : ///
10CM SOLAR FLUX        : 167
AK CHAMBON LA FORET    : 006
AK WINGST              : 002
ESTIMATED AP           : 002
ESTIMATED ISN          : 215, BASED ON 17 STATIONS.

NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM Catania/NOAA RADIO_BURST_TYPES 
25  1311  1321 1327 ////// M1.0          59/3638      V/3III/1 
25  1703  1712 1716 ////// M1.3          59/3638      III/2 
END

BT
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