Viewing archive of Monday, 17 April 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Apr 17 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
17 Apr 2023	176	006
18 Apr 2023	176	004
19 Apr 2023	176	010

Bulletin

Solar flaring activity was at low levels in the past 24 hours. There are nine numbered regions on the visible solar disc, approximately half of which are small and simple. The largest active region, NOAA 3282 (beta-gamma), has produced only a couple of isolated C-class flares. The second largest region, NOAA 3281 (beta-gamma), has remained stable and inactive. Multiple low C-class flares were produced by NOAA AR 3280 (beta- gamma) and NOAA AR 3283 (beta-gamma), including a C7.0 flare, peak time 06:39 UTC on April 17th. C9.1 flare, peak time 17:44 UTC on April 16th, was produced by an active region rotating from the east limb. The remaining low C-class flaring activity was produced by NOAA AR 3279 (beta). The solar flaring activity is expected to remain at low background levels over the next 24 hours with possible isolated M-class flaring.

A filament erupted to the north-west of NOAA AR 3282 around 05:30 UTC on April 17th. An associated coronal mass ejection (CME) is clearly visible in the SDO/AIA 304 images. The CME is currently not detected in the available coronagraph imagery. The bulk of the ejection appears directed to the north-west, but a small Earth-directed component remains possible. Due to lack of coronagraph imagery it is difficult to estimate the CME speed and a possible glancing blow arrival time, but due to the nature of the CME any expected impact is minimal. A glancing blow from the large filament eruption in the northern hemisphere and related CME lift-off around 11:00 UTC on April 15th could be expected to reach Earth on April 19th. A glancing blow from the CME related to a filament eruption around 23:30 UTC on April 15 might arrive to Earth late on April 19th or early on April 20th. No other Earth-directed CMEs have been detected in the limited available coronagraph imagery.

Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to remain so in the next 24 hours. The greater than 2 MeV electron flux has been below the1000 pfu threshold and is expected to remain so. The 24h electron fluence was at nominal levels and is expected to remain so over the next 24 hours.

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) were at background slow solar wind levels. The solar wind velocity varied in the range of 299 to 399 km/s. The interplanetary magnetic field registered a maximum value of 9.7 nT with a minimum Bz of -8.3 nT. The B field varied between the positive and the negative sector (directed away from and towards the Sun). Slow solar wind conditions are expected to prevail until the first expected glancing blow arrival on April 19th.

The geomagnetic conditions over the past 24 hours were globally quiet. Locally in Belgium several unsettled periods were registered. Mostly quiet to unsettled geomagnetic conditions are expected over the next 24 hours with possible, but less likely isolated active periods.

Today's estimated international sunspot number (ISN): 140, based on 07 stations.

Solar indices for 16 Apr 2023

Wolf number Catania	///
10cm solar flux	178
AK Chambon La Forêt	007
AK Wingst	004
Estimated Ap	004
Estimated international sunspot number	196 - Based on 13 stations

Noticeable events summary

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

All times in UTC

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