SIDC Ursigram

:Issued: 2024 Apr 20 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 40420
SIDC SOLAR BULLETIN 20 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 20 Apr 2024  10CM FLUX: 220 / AP: 017
PREDICTIONS FOR 21 Apr 2024  10CM FLUX: 215 / AP: 022
PREDICTIONS FOR 22 Apr 2024  10CM FLUX: 210 / AP: 017

Solar Active Regions and flaring: Solar flaring activity was at moderate
levels, with multiple C-class flares and one M-class flare recorded in the
past 24 hours. The largest flare of the period was an M1.0 flare, peaking
at 13:06 UTC on Apr 19, associated with NOAA AR 3647 (beta-delta class).
There are currently 14 numbered active regions on the visible disk. NOAA AR
3639 (beta-gamma) is the largest region on disk but was inactive.  NOAA AR
3635 is expected to rotate over the west limb in the next hours.  Other
regions on the disc have simple configuration of their photospheric
magnetic field (alpha and beta). The solar flaring activity is expected to
be at moderate levels over the next 24 hours, with M-class flares possible
and a low chance for X-class flare.

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

Solar wind: Over the past 24 hours, the solar wind parameters were slightly
disturbed under the ICME influence. The total magnetic field reached 18 nT
at 14:13 UTC on April 19, later decreasing to the values around 5 nT. The
solar wind speed ranged between 400 km/s and 550 km/s. The southward
component of the interplanetary magnetic field fluctuated between -16 nT
and 7 nT. The interplanetary magnetic field phi angle varied between being
directed towards the Sun to being directed away from the Sun. The effects
of the CME are expected to slowly wane in the next 24 hours with a chance
of a further enhancement on Apr 20 - Apr 21 due to the arrival of a high-
speed stream from a negative polarity coronal hole and anticipated arrival
of CMEs from Apr 17 - Apr 18, however with low confidence.

Geomagnetism: Geomagnetic conditions reached strong storm levels globally
(NOAA-Kp = 7) between 18:00 and 21:00 UTC on Apr 19. Locally over Belgium,
only minor geomagnetic storm conditions were observed (K-Bel = 5).
Conditions then reduced to quiet to unsettled levels. The strong storm
period was reached due to the prolonged period of negative Bz.
Predominantly unsettled geomagnetic conditions are expected on Apr 20-21
with a chance of reaching active and minor storm conditions due to expected
HSS arrival and potential CMEs arrivals.

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  : 218, BASED ON 13 STATIONS.

SOLAR INDICES FOR 19 Apr 2024
WOLF NUMBER CATANIA    : ///
10CM SOLAR FLUX        : 213
AK CHAMBON LA FORET    : 042
AK WINGST              : 041
ESTIMATED AP           : 040
ESTIMATED ISN          : 231, BASED ON 19 STATIONS.

NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM Catania/NOAA RADIO_BURST_TYPES 
19  1253  1306 1323 ////// M1.0          60/3647      III/2 
END

BT
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