SIDC ursigram

:Issued: 2024 Apr 19 1230 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 40419
SIDC SOLAR BULLETIN 19 Apr 2024, 1230UT
SIDC FORECAST 
SOLAR FLARES  : M-class flares expected (probability >=50%)
GEOMAGNETISM  : Active conditions expected (A>=20 or K=4)
SOLAR PROTONS : Quiet
PREDICTIONS FOR 19 Apr 2024  10CM FLUX: 220 / AP: 022
PREDICTIONS FOR 20 Apr 2024  10CM FLUX: 216 / AP: 024
PREDICTIONS FOR 21 Apr 2024  10CM FLUX: 210 / AP: 022

Solar Active Regions and flaring: Solar flaring activity was at moderate
level, with multiple C-class flares and three M-class flares recorded in
the past 24 hours. The largest flare of the period was an M2.1 flare,
peaking at 04:53 UTC on Apr 19, associated with NOAA AR 3647 (beta-delta
class). This region was the main driver of the flaring activity observed
over the past 24 hours together with NOAA AR 3645 (beta class). Low flaring
activity was also produced by NOAA AR 3635 (beta class) and NOAA AR 3639
(beta-gamma class). Other regions on the disc have simple configuration of
their photospheric magnetic field (alpha and beta) and did not show any
significant flaring activity. The solar flaring activity is expected to be
at moderate levels over the next 24 hours, with M-class flares possible and
a chance for X-class flare.

Coronal mass ejections: Multiple CMEs, directed towards south-east from the
Earth's perspective, were observed in SOHO/LASCO-C2 starting from
approximately 17:16 on Apr 17, likely related to the flaring activity from
NOAA AR 3638 and 3643. While bulk of the CME is off the Sun-Earth line, a
glancing blow from these CMEs could be possible on Apr 21 - 22, although
with low confidence.

Solar wind: At the beginning of the period, the solar wind parameters were
reflecting return to slow solar wind conditions. The solar wind speed
decreased from the values about 360 km/s to 310 km/s; the total
interplanetary magnetic field was below 5 nT. The solar wind conditions
became slightly disturbed from around 04:12 UTC on April 19, with the total
interplanetary magnetic field reaching the values up to 16 nT. The
southward component of the interplanetary magnetic field fluctuated between
-12 nT and 5 nT. This is probably associated with the arrival of a faint
partial halo CME observed on Apr 15. The solar wind conditions are expected
to remain slightly elevated due to the ICME passage with a chance of a
further weak enhancement late on Apr 20 - Apr 21 due to the arrival of a
high-speed stream from a negative polarity coronal hole, that started to
cross the central meridian on Apr 17 and a possible ICMEs arrival.

Geomagnetism: The geomagnetic conditions over the past 24 hours were quiet
to active globally (NOAA-Kp=1-4). Locally only quiet to
unsettled(K-Bel=2-3) conditions were observed over Belgium. Mostly
unsettled to active geomagnetic conditions are expected for the next 24
hours, with a chance of reaching minor storm levels due to ongoing ICME
influence and expected HSS arrival.

Proton flux levels: Over the past 24 hours the greater than 10 MeV GOES
proton flux was at nominal levels and is expected to remain so with
possible enhancements in case of increased levels of solar activity over
the next days.

Electron fluxes at GEO: The greater than 2 MeV electron flux, as measured
by the GOES-16 satellite, remained below the 1000 pfu threshold. It is
expected to remain below the threshold during the next 24 hours. The 24
hour electron fluence was at normal levels and is expected to remain at
these levels for the following 24 hours.


TODAY'S ESTIMATED ISN  : 245, BASED ON 11 STATIONS.
99999

SOLAR INDICES FOR 18 Apr 2024
WOLF NUMBER CATANIA    : 225
10CM SOLAR FLUX        : 227
AK CHAMBON LA FORET    : 009
AK WINGST              : 004
ESTIMATED AP           : 004
ESTIMATED ISN          : 214, BASED ON 23 STATIONS.

NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM Catania/NOAA RADIO_BURST_TYPES 
18  1922  2001 2012 S12E17 M1.6 SF       60/3645      III/1 
18  2012  2016 2021 S12E17 M1.6 SF       ///3647      III/1 
19  0440  0453 0503 N20W58 M2.1 SF       60/3647      VI/1III/1 
END

UMAGF 30503 40419 1004/ 18060 1/009 21211 31212
UMAGF 31523 40419 0000/ 18003 1/004 22101 31112
BT
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