Viewing archive of Wednesday, 12 April 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Apr 12 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
12 Apr 2023	144	003
13 Apr 2023	144	004
14 Apr 2023	144	016

Bulletin

Over the past 24 hours, the solar activity has been at very low levels with 6 C-class flares reported. The strongest flare was a C6.1 flare which originated from Catania sunspot group 55 (NOAA AR 3276) and had a peak time at 11:53 UT on April 12. This sunspot group has rotated onto the visible side of the solar disk just recently. A total of five numbered active regions are observed on the visible side of the solar disk. For the next 24 hours, we expect C-class flares and possibly isolated M-class flares.

During the last 24 hours there were no potentially Earth-directed coronal mass ejections (CMEs) detected in the available coronagraph observations.

The greater than 10 MeV proton flux was at nominal levels over the past 24 hours and is expected to remain so. 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 remain so over the next 24 hours.

Over the past 24 hours, the solar wind speed decreased from about 440 km/s to 350 km/s, returning back to slow ambient wind conditions. We expect the slow solar wind conditions to persist in the coming hours. From late April 13 onwards, we are expecting the arrival of another high speed stream, associated with the positive polarity coronal hole in the Southern hemisphere, with a possibility of a glancing blow associated with the CME observed on April 9. Another positive polarity coronal hole in the Northern hemisphere is crossing the central meridian today and we expect the associated high speed stream to arrive late April 14.

During the last 24 hours the geomagnetic conditions were quiet and we expect such a geomagnetic conditions to persist in the coming hours.

Today's estimated international sunspot number (ISN): 127, based on 10 stations.

Solar indices for 11 Apr 2023

Wolf number Catania	136
10cm solar flux	143
AK Chambon La Forêt	009
AK Wingst	004
Estimated Ap	004
Estimated international sunspot number	107 - Based on 25 stations

Noticeable events summary

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

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