Viewing archive of Sunday, 16 April 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Apr 16 1237 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
16 Apr 2023	180	004
17 Apr 2023	176	004
18 Apr 2023	176	007

Bulletin

The solar flaring activity was at low levels over the past 24 hours with 19 low level C-class flares reported. The C-class flares originated from a variety of active regions including Catania sunspot group number 57 (NOAA AR 3280), number 59 (NOAA AR 3282) and number 60 (NOAA AR 3281). A total of 8 numbered active regions are presently observed on the visible side of the solar disk, all with a simple configuration of their photospheric magnetic field (alpha or beta), except for Catania sunspot group number 57 (NOAA AR 3280) and number 59 (NOAA AR 3282) which have a beta-gamma configuration of its photospheric magnetic field. For the next 24 hours, we expect C-class flares and possibly isolated M-class flares. The flaring activity originating from the Catania sunspot group number 57 (NOAA AR 3280), which is currently well-connected to the Earth, could be associated with a particle event.

During the last 24 hours one halo CME has been observed by SOHO/LASCO C2 and C3 coronagraphs. It was seen for the first time at 01:25UT on April 16 in SOHO/LASCO C2 field of view. This CME is related to the filament eruption around 23:00 UT on April 15 in the North-West quadrant near NOAA AR 3277. We expect the CME to arrive early on late April 18 or the first half of April 19th.

The greater than 10 MeV proton flux was at nominal levels over the past 24 hours. Due to the moderate flaring activity it is possible that the greater than 10 MeV proton flux may exceed this threshold over the next 24 hours if there are any high energy flares and eruptions. The greater than 2 MeV electron flux has been below the 1000 pfu threshold and is expected to remain so. The 24h electron fluence was at normal levels and is expected to stay below the threshold over the next 24 hours.

Over the past 24 hours, the solar wind speed was in the slow solar wind regime with values between 320 km/s and 350km/s. The interplanetary magnetic field strength was about 5-6 nT with a mostly South-ward oriented Bz-component of the magnetic field. For the next 24 hours, we expect the slow solar wind regime to persist, with a possibility of a small enhancement from a glancing coronal hole influence.

During the last 24 hours the geomagnetic conditions were quiet to unsettled and we expect quiet to unsettled geomagnetic conditions in the next 24 hours.

Today's estimated international sunspot number (ISN): 197, based on 06 stations.

Solar indices for 15 Apr 2023

Wolf number Catania	///
10cm solar flux	176
AK Chambon La Forêt	013
AK Wingst	008
Estimated Ap	014
Estimated international sunspot number	178 - Based on 24 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive

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