SIDC ursigram

:Issued: 2024 Apr 24 1304 UTC
:Product: documentation at http://www.sidc.be/products/tot
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# DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC     #
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SIDC URSIGRAM 40424
SIDC SOLAR BULLETIN 24 Apr 2024, 1304UT
SIDC FORECAST 
SOLAR FLARES  : M-class flares expected (probability >=50%)
GEOMAGNETISM  : Quiet (A<20 and K<4)
SOLAR PROTONS : Quiet
PREDICTIONS FOR 24 Apr 2024  10CM FLUX: 220 / AP: 003
PREDICTIONS FOR 25 Apr 2024  10CM FLUX: 220 / AP: 008
PREDICTIONS FOR 26 Apr 2024  10CM FLUX: 220 / AP: 015

Solar Active Regions and flaring: Solar flaring activity remained at
moderate levels in the past 24 hours with multiple M-class flares. There
are 15 numbered and several unnumbered active regions on the visible solar
disc. NOAA AR 3645 (beta-gamma) remains the largest region, followed by
NOAA AR 3646 (beta-gamma), NOAA AR 3647 (beta-gamma) and NOAA AR 3639
(beta-gamma). The strongest activity was M2.9 flare, start time 17:33 UTC,
end time 17:52 UTC, peak time 17:44 UTC on April 23rd produced by NOAA AR
3638 (beta). Other regions which contributed to the low M-class flaring
observed are NOAA AR 3645 and NOAA AR 3647. NOAA AR 3546 and NOAA AR 3654
(beta) contributed to the high C-class flaring. The solar flaring activity
is expected to remain at moderate levels over the next days with likely
further M-class flaring and 20% chance for isolated X-class flaring.

Coronal mass ejections: Further analysis of the multiple coronal mass
ejections (CMEs) detected by LASCO/C2 during the UTC night of April 23rd
suggests no expected impact on Earth. A slow partial halo CME is visible in
the LASCO/C2 coronagraph imagery starting at 18:00 UTC on April 23rd. The
CME is propagating to the south-west and has an estimated projected
velocity around 400 km/s. The eruption appears related to the M2.9 flare,
peak time 17:44 UTC on April 23rd, produced by NOAA AR 3638. An associated
type II radio emission was observed starting at 17:10 UTC on April 23rd
with estimated velocity of 358 km/s. Analysis of this event suggests no to
possibly very low impact on Earth late on April 27th.
No other Earth-directed coronal mass ejections (CMEs) have been detected in
the available coronagraph imagery over the past 24 hours.

Coronal holes: A small positive polarity mid-latitude coronal hole is
currently residing on the central meridian in the southern hemisphere. The
high speed stream emanating from it might arrive to Earth on April 27th-
April 28th.

Solar wind: Over the past 24 hours the solar wind parameters (ACE and
DSCOVR) were indicative of background slow solar wind regime. The solar
wind velocity was mostly in the range between 350 km/s to 400 km/s. The
interplanetary magnetic field was unremarkable with a maximum value of 6.4
nT and a minimum Bz of -5.7 nT. Around 06:00 UTC on April 24th the B field
phi angle switched from the negative to the positive sector (directed away
from the Sun). The solar wind conditions are expected to remain at these
levels on April 24th with possible mild enhancements on April 25th - April
26th and further on April 27th-April 28th should any of the expected high
speed streams arrive to Earth.

Geomagnetism: The geomagnetic conditions over the past 24 hours were quiet
to unsettled. Quiet to unsettled geomagnetic conditions are expected
throughout April 24th. Quiet to active conditions with chances for isolated
minor storms are anticipated for late April 25th-April 28th.

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 GOES 16 electron flux as
measured by GOES 16 was below the 1000 pfu threshold and is expected to
remain so over the next 24h. The greater than 2 MeV electron flux as
measured by GOES 18 exceeded the1000 pfu threshold in the late UTC
afternoon on April 23rd and is expected to repeat this pattern on April
24th. The 24h electron fluence was at nominal level and is expected to
remain so.


TODAY'S ESTIMATED ISN  : 258, BASED ON 16 STATIONS.
99999

SOLAR INDICES FOR 23 Apr 2024
WOLF NUMBER CATANIA    : 308
10CM SOLAR FLUX        : 219
AK CHAMBON LA FORET    : 011
AK WINGST              : 007
ESTIMATED AP           : 007
ESTIMATED ISN          : 274, BASED ON 20 STATIONS.

NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM Catania/NOAA RADIO_BURST_TYPES 
23  1733  1744 1752 S08W59 M2.9 SF       60/3645      III/3II/2 
24  0013  0029 0038 S11W63 M1.7 SF       59/3638      
24  0230  0239 0244 ////// M1.8          59/3638      V/2 
END

UMAGF 30503 40424 1004/ 23063 1/011 21211 33211
UMAGF 31523 40424 0000/ 23002 1/007 21122 32232
BT
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